The significance of power factor correction (PFC) has long been visualized as a technology requirement for improving the efficiency of a power system network by compensating for the fundamental reactive power generated or consumed by simple inductive or capacitive loads. With the Information Age in full swing, the growth of high reliability, low cost electronic products have led utilities to escalate their power quality concerns created by the increase of such “switching loads.” These products include: entertainment devices such as Digital TVs, DVDs, and audio equipment; information technology devices such as PCs, printers, and fax-machines; variable speed motor drives for HVAC and white goods appliances; food preparation and cooking products such as microwaves and cook tops; and lighting products, which include electronic ballasts, LED and fluorescent lamps, and other power conversion devices that operate a variety of lamps. The drivers that have resulted in this proliferation are a direct result of the availability of low-cost switch-mode devices and control circuitry in all major end-use segments: residential, commercial, and industrial.
In order to keep power quality under the limits proposed by standards, it is required to incorporate some sort of compensation. There are two basic types of PFC circuits: active and passive. The simplest power factor correctors can be implemented using a passive filter to suppress the harmonics in conjunction with capacitors or inductors to generate or consume the fundamental reactive power, respectively. Active power factor correction circuits have proven to be more effective, generally integrated with the switch-mode circuitry, and actively control the input current of the load. This enables the most efficient delivery of electrical power from the power grid to the load. The demand for new smart, green products has set the stage for a worldwide migration from antiquated passive circuits to active correctors as well as from traditional analog technology to digital techniques. New digital active power factor correction delivers better full- and light-load power efficiency while lowering system costs, enabling smaller designs and providing a clear path for further feature enhancements and improved competitive positioning for a whole host of consumer and industrial products. Cirrus Logic’s novel advances in digital active PFC technology signify a major enabling element in the development of the newest generation of low cost, energy-efficient switch mode products.
1. The document discusses a static synchronous series compensator (SSSC), a type of flexible AC transmission system (FACTS) device that controls electric power flow by injecting a controlled voltage in series with a transmission line.
2. The SSSC can provide either capacitive or inductive compensation, depending on whether the injected voltage lags or leads the line current.
3. Digital simulations show that the SSSC can increase or decrease the dynamic power flow in the transmission line depending on the mode of compensation.
This document discusses FACTS (Flexible AC Transmission System) devices. It defines FACTS as using static power electronics controllers to control reactive power and enhance AC transmission system controllability. The document outlines the necessity of FACTS devices to compensate for reactive power and improve power transmission efficiency. It describes different types of FACTS controllers including shunt controllers like STATCOM, TCR, TSR, and TSC. The benefits of FACTS in providing fast, flexible control of transmission parameters and improving power flow capability are also summarized.
Gcsc gto thyristor controlled series capacitorLEOPAUL23
The document discusses the GTO Thyristor Controlled Series Capacitor (GCSC), which consists of a fixed capacitor in parallel with an anti-parallel GTO pair. The GCSC can continuously vary the voltage across the capacitor between zero and its maximum value by controlling the turn-off delay angle of the thyristor valve. It works by closing and opening the thyristor valve in synchronism with the supply frequency. The GCSC can operate in either voltage compensating mode, to maintain a rated compensating voltage over a range of line currents, or in reactance compensating mode, to maintain a maximum rated compensating reactance at any line current.
The significance of power factor correction (PFC) has long been visualized as a technology requirement for improving the efficiency of a power system network by compensating for the fundamental reactive power generated or consumed by simple inductive or capacitive loads. With the Information Age in full swing, the growth of high reliability, low cost electronic products have led utilities to escalate their power quality concerns created by the increase of such “switching loads.” These products include: entertainment devices such as Digital TVs, DVDs, and audio equipment; information technology devices such as PCs, printers, and fax-machines; variable speed motor drives for HVAC and white goods appliances; food preparation and cooking products such as microwaves and cook tops; and lighting products, which include electronic ballasts, LED and fluorescent lamps, and other power conversion devices that operate a variety of lamps. The drivers that have resulted in this proliferation are a direct result of the availability of low-cost switch-mode devices and control circuitry in all major end-use segments: residential, commercial, and industrial.
Loading Capability Limits of Transmission LinesRaja Adapa
This document discusses the four main loading capability limits of transmission lines: thermal, voltage, dielectric, and stability limits. The thermal limit depends on ambient temperature, wind conditions, conductor size and is usually the main limiting factor. Voltage limits require the transmission voltage to be maintained within a specified range, like plus/minus 5% of nominal. The dielectric limit concerns insulation and allows for some increase in normal operating voltage. Stability limits involve ensuring the power system remains stable after the loss of a single element to prevent cascading outages. FACTS technology can help utilize more of the thermal limits and improve stability.
The concept of FACTS (Flexible Alternating Current Transmission System) refers to a family of power electronics-based devices able to enhance AC system controllability and stability and to increase power transfer capability.
This document discusses transient problems related to load switching that can cause nuisance tripping of adjustable speed drives (ASDs). It notes that ASDs use voltage source inverters with capacitors in the DC link, making them sensitive to overvoltage transients from utility capacitor switching or load switching. Such transients from load switching can generate high frequency impulses when energizing inductive loads like relays or contactors. Simultaneously energizing large transformers and capacitor banks can also cause dynamic overvoltage problems if system resonances occur. Protection methods include electrical separation of sensitive equipment, as well as using filters, isolation transformers, and shielding.
1. The document discusses a static synchronous series compensator (SSSC), a type of flexible AC transmission system (FACTS) device that controls electric power flow by injecting a controlled voltage in series with a transmission line.
2. The SSSC can provide either capacitive or inductive compensation, depending on whether the injected voltage lags or leads the line current.
3. Digital simulations show that the SSSC can increase or decrease the dynamic power flow in the transmission line depending on the mode of compensation.
This document discusses FACTS (Flexible AC Transmission System) devices. It defines FACTS as using static power electronics controllers to control reactive power and enhance AC transmission system controllability. The document outlines the necessity of FACTS devices to compensate for reactive power and improve power transmission efficiency. It describes different types of FACTS controllers including shunt controllers like STATCOM, TCR, TSR, and TSC. The benefits of FACTS in providing fast, flexible control of transmission parameters and improving power flow capability are also summarized.
Gcsc gto thyristor controlled series capacitorLEOPAUL23
The document discusses the GTO Thyristor Controlled Series Capacitor (GCSC), which consists of a fixed capacitor in parallel with an anti-parallel GTO pair. The GCSC can continuously vary the voltage across the capacitor between zero and its maximum value by controlling the turn-off delay angle of the thyristor valve. It works by closing and opening the thyristor valve in synchronism with the supply frequency. The GCSC can operate in either voltage compensating mode, to maintain a rated compensating voltage over a range of line currents, or in reactance compensating mode, to maintain a maximum rated compensating reactance at any line current.
The significance of power factor correction (PFC) has long been visualized as a technology requirement for improving the efficiency of a power system network by compensating for the fundamental reactive power generated or consumed by simple inductive or capacitive loads. With the Information Age in full swing, the growth of high reliability, low cost electronic products have led utilities to escalate their power quality concerns created by the increase of such “switching loads.” These products include: entertainment devices such as Digital TVs, DVDs, and audio equipment; information technology devices such as PCs, printers, and fax-machines; variable speed motor drives for HVAC and white goods appliances; food preparation and cooking products such as microwaves and cook tops; and lighting products, which include electronic ballasts, LED and fluorescent lamps, and other power conversion devices that operate a variety of lamps. The drivers that have resulted in this proliferation are a direct result of the availability of low-cost switch-mode devices and control circuitry in all major end-use segments: residential, commercial, and industrial.
Loading Capability Limits of Transmission LinesRaja Adapa
This document discusses the four main loading capability limits of transmission lines: thermal, voltage, dielectric, and stability limits. The thermal limit depends on ambient temperature, wind conditions, conductor size and is usually the main limiting factor. Voltage limits require the transmission voltage to be maintained within a specified range, like plus/minus 5% of nominal. The dielectric limit concerns insulation and allows for some increase in normal operating voltage. Stability limits involve ensuring the power system remains stable after the loss of a single element to prevent cascading outages. FACTS technology can help utilize more of the thermal limits and improve stability.
The concept of FACTS (Flexible Alternating Current Transmission System) refers to a family of power electronics-based devices able to enhance AC system controllability and stability and to increase power transfer capability.
This document discusses transient problems related to load switching that can cause nuisance tripping of adjustable speed drives (ASDs). It notes that ASDs use voltage source inverters with capacitors in the DC link, making them sensitive to overvoltage transients from utility capacitor switching or load switching. Such transients from load switching can generate high frequency impulses when energizing inductive loads like relays or contactors. Simultaneously energizing large transformers and capacitor banks can also cause dynamic overvoltage problems if system resonances occur. Protection methods include electrical separation of sensitive equipment, as well as using filters, isolation transformers, and shielding.
FACTS devices are power electronic systems that provide control of AC transmission system parameters to improve power transfer capability and grid stability. FACTS stands for Flexible Alternating Current Transmission System and includes static equipment like STATCOMs. FACTS devices are classified as series controllers that inject voltage and shunt controllers that inject current. They are used to control impedance, voltage, current and phase angle to enhance controllability, reliability and power quality on transmission lines. While expensive, FACTS provide benefits like increased transmission capacity, damping of oscillations and improved stability.
This document discusses different methods for generating high voltages and currents, including cascade transformers, resonant transformers, and Tesla coils for AC voltages, and single-stage and Marx generators for impulse voltages. It also covers impulse current generation using a bank of parallel capacitors discharged through an R-L circuit. Cascade transformers consist of multiple transformer stages connected in series to achieve high voltages. Resonant transformers use tuning of the secondary circuit. Tesla coils produce high frequency AC through magnetic coupling of primary and secondary air-core coils.
FACTS DEVICES AND POWER SYSTEM STABILITY pptMamta Bagoria
This presentation provides an overview of Flexible AC Transmission Systems (FACTS) and power system stability. It defines FACTS as using power electronics to control power flow and enhance transmission system capacity and stability. The document outlines different types of FACTS controllers including series compensation and shunt compensation. It also classifies power system stability into rotor angle stability, voltage stability, and frequency stability and discusses factors that can lead to losses of each type of stability.
An induction energy meter measures electrical energy consumption over time using the principle of electromagnetic induction. It consists of a driving system that induces eddy currents in a rotating aluminum disk via voltage and current coils, a braking system that regulates the disk's speed, and a registering system that counts disk rotations to display energy used in kilowatt-hours. Potential errors from speed, phase, friction, creep, or temperature can be corrected by adjusting magnetic fields or components.
The document discusses Thyristor Controlled Series Compensation (TCSC), a FACTS device that uses thyristors to control the capacitive reactance of transmission lines. TCSC can enhance power flow, limit fault current, improve stability and transients. It introduces benefits like mitigating subsynchronous resonance risks, damping power oscillations, and improving post-contingency stability. TCSC operates in modes like blocking, bypass, capacitive boost and inductive boost to accurately regulate power flow and damp oscillations while increasing transmission capacity and stability.
These slides present the introduction to FACTS devices. Later we will discuss about its modelling and control aspect applications. This comes under the topic on power electronics application in smart and microgrid systems.
This document provides information about flexible AC transmission systems (FACTS) including opportunities for FACTS, types of FACTS controllers, and their relative importance. It discusses how FACTS controllers can control parameters like line impedance, phase angle, and voltage injection to regulate power flow. The key types of FACTS controllers are series, shunt, and combined series-series or series-shunt configurations. Series controllers directly impact current and power flow, while shunt controllers control voltage. Combined controllers allow coordinated control and real power transfer between elements.
This document discusses Flexible AC Transmission Systems (FACTS) controllers. It defines FACTS controllers as power electronic devices that control parameters of AC transmission systems. The document describes several types of FACTS controllers including STATCOM, SVC, TCSC, SSSC, and UPFC. It explains how each type of controller works and its benefits such as increasing power transfer capability and network reliability.
The electricity supply industry is undergoing a profound transformation worldwide. Market forces, scarcer natural resources, and an ever-increasing demand for electricity are some of the drivers responsible for such unprecedented change. Against this background of rapid evolution, the expansion programs of many utilities are being thwarted by a variety of well-founded, environment, land-use, and regulatory pressures that prevent the licensing and building of new transmission lines and electricity generating plants.
The document discusses the basic types of FACTS (Flexible AC Transmission System) controllers, including series controllers that inject voltage in series with a line, shunt controllers that inject current, and combined series-shunt controllers. FACTS controllers are used to control power flow and improve voltage profiles by injecting currents and voltages. The choice of controller depends on the desired control over current, power flow, damping of oscillations, and improvement of voltage.
Reactive power management and voltage control by using statcomHussain Ali
This document summarizes the use of STATCOM devices for reactive power management and voltage control in transmission lines. It defines reactive power and explains the need for reactive power compensation. It then defines FACTS devices and specifically STATCOMs, describing their basic structure and principle of operation for generating and absorbing reactive power. The document discusses how STATCOMs can provide benefits like reactive power control, voltage regulation, and increased transmission capacity. It provides an example of a 500 MVAR STATCOM installed between Qatar and Bahrain for reactive power compensation and concludes that STATCOMs allow tighter voltage control and improved reliability compared to traditional capacitor banks.
This document summarizes a seminar on reactive power compensation. It discusses the different types of power, including active power, reactive power, and apparent power. It explains that reactive power is needed by magnetic equipment like transformers and motors to produce magnetizing flux. The document outlines the need for reactive power compensation to improve power factor, reduce losses, increase capacity, and improve voltage regulation. It then describes different compensation techniques like shunt compensation using capacitors at the load, substation, or transmission level. The document also discusses synchronous condensers and power electronics devices like thyristor controlled reactors, static VAR compensators, and thyristor controlled series compensators for reactive power compensation.
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system.
In conventional AC transmission system, the ability to transfer AC power is limited by several factors like thermal limits, transient stability limit, voltage limit, short circuit current limit etc. These limits define the maximum electric power which can be efficiently transmitted through the transmission line without causing any damage to the electrical equipments and the transmission lines. This is normally achieved by bringing changes in the power system layout. However this is not feasible and another way of achieving maximum power transfer capability without any changes in the power system layout. Also with the introduction of variable impedance devices like capacitors and inductors, whole of the energy or power from the source is not transferred to the load, but a part is stored in these devices as reactive power and returned back to the source. Thus the actual amount of power transferred to the load or the active power is always less than the apparent power or the net power. For ideal transmission the active power should be equal to the apparent power. In other words, the power factor (the ratio of active power to apparent power) should be unity. This is where the role of Flexible AC transmission System comes.
This document discusses power system security. It defines power system security as the probability of the system operating within acceptable ranges given potential changes or contingencies. It outlines the key steps in power system security including: (1) monitoring the current system state, (2) contingency analysis to evaluate potential risks, and (3) corrective action analysis to maintain security through preventative or automatic corrective actions.
In the modern power system the reactive power compensation is one of the main issues, the transmission of active power requires a difference in angular phase between voltages at the sending and receiving points (which is feasible within wide limits), whereas the transmission of reactive power requires a difference in magnitude of these same voltages (which is feasible only within very narrow limits). The reactive power is consumed not only by most of the network elements, but also by most of the consumer loads, so it must be supplied somewhere. If we can't transmit it very easily, then it ought to be generated where it is needed." (Reference Edited by T. J. E. Miller, Forward Page ix).Thus we need to work on the efficient methods by which VAR compensation can be applied easily and we can optimize the modern power system. VAR control technique can provides appropriate placement of compensation devices by which a desirable voltage profile can be achieved and at the same time minimizing the power losses in the system. This report discusses the transmission line requirements for reactive power compensation. In this report thyristor switched capacitor is explained which is a static VAR compensator used for reactive power management in electrical systems.
Seminar Topic For Electrical and Electronics Engineering (EEE)
This document discusses different methods for generating high AC and impulse voltages for testing purposes. It describes cascade transformers which can produce voltages over 300kV by connecting multiple transformer units in series. It also covers Marx circuits which charge multiple capacitors in parallel and discharge them in series to achieve high impulse voltages. Switching surges with long durations can be created using a transformer excited by a DC voltage that produces damped oscillations.
This document discusses issues related to interconnecting microgrids. It describes how a DC microgrid system utilizes a DC bus to distribute power from photovoltaic units and battery storage to local households. Interconnection can be done directly through switchgear or power electronic interfaces. Key issues that can arise include voltage and frequency fluctuations that occur due to imbalance between supply and demand, power factor correction needs, and harmonics produced by some loads. Unintentional islanding is also a safety concern that must be addressed when connecting microgrids to the main power grid.
Design, Planning and Layout of high voltage laboratory vishalgohel12195
Design, Planning and Layout of high voltage laboratory
Test equipment provided in high voltage lab
Activity and study in high voltage lab
Classification of high voltage lab
Clearance of high voltage Lab
Layout of high voltage lab
Safety
Shielding of the high voltage lab
The UPFC is a FACTS device that can control all three parameters of line power flow - voltage, impedance, and phase angle. It consists of two voltage source inverters, one connected in series with the transmission line and one connected in shunt. The shunt inverter controls reactive power flow and voltage, while the series inverter controls real and reactive power flow by injecting a controllable voltage in series with the line. Control schemes for the UPFC include phase angle control, cross-coupling control, and a generalized control scheme that provides damping against power swings for improved stability. The UPFC offers benefits like improved power transfer capacity, transient stability, and independent control of real and reactive power flows.
This document presents a proposal for designing, simulating, and implementing a Unified Power Flow Controller (UPFC) for a power system model. The UPFC is introduced as a versatile Flexible AC Transmission Systems device that can control active and reactive power flow. The proposal outlines objectives to design and simulate a UPFC model in MATLAB/Simulink, implement the hardware, compare experimental and simulation results, and integrate the controllable UPFC into the university's power system model to improve power quality. A timeline is proposed from June 2016 to March 2017 to conduct background research, system design, simulation, hardware implementation, results analysis, and reporting.
FACTS devices are power electronic systems that provide control of AC transmission system parameters to improve power transfer capability and grid stability. FACTS stands for Flexible Alternating Current Transmission System and includes static equipment like STATCOMs. FACTS devices are classified as series controllers that inject voltage and shunt controllers that inject current. They are used to control impedance, voltage, current and phase angle to enhance controllability, reliability and power quality on transmission lines. While expensive, FACTS provide benefits like increased transmission capacity, damping of oscillations and improved stability.
This document discusses different methods for generating high voltages and currents, including cascade transformers, resonant transformers, and Tesla coils for AC voltages, and single-stage and Marx generators for impulse voltages. It also covers impulse current generation using a bank of parallel capacitors discharged through an R-L circuit. Cascade transformers consist of multiple transformer stages connected in series to achieve high voltages. Resonant transformers use tuning of the secondary circuit. Tesla coils produce high frequency AC through magnetic coupling of primary and secondary air-core coils.
FACTS DEVICES AND POWER SYSTEM STABILITY pptMamta Bagoria
This presentation provides an overview of Flexible AC Transmission Systems (FACTS) and power system stability. It defines FACTS as using power electronics to control power flow and enhance transmission system capacity and stability. The document outlines different types of FACTS controllers including series compensation and shunt compensation. It also classifies power system stability into rotor angle stability, voltage stability, and frequency stability and discusses factors that can lead to losses of each type of stability.
An induction energy meter measures electrical energy consumption over time using the principle of electromagnetic induction. It consists of a driving system that induces eddy currents in a rotating aluminum disk via voltage and current coils, a braking system that regulates the disk's speed, and a registering system that counts disk rotations to display energy used in kilowatt-hours. Potential errors from speed, phase, friction, creep, or temperature can be corrected by adjusting magnetic fields or components.
The document discusses Thyristor Controlled Series Compensation (TCSC), a FACTS device that uses thyristors to control the capacitive reactance of transmission lines. TCSC can enhance power flow, limit fault current, improve stability and transients. It introduces benefits like mitigating subsynchronous resonance risks, damping power oscillations, and improving post-contingency stability. TCSC operates in modes like blocking, bypass, capacitive boost and inductive boost to accurately regulate power flow and damp oscillations while increasing transmission capacity and stability.
These slides present the introduction to FACTS devices. Later we will discuss about its modelling and control aspect applications. This comes under the topic on power electronics application in smart and microgrid systems.
This document provides information about flexible AC transmission systems (FACTS) including opportunities for FACTS, types of FACTS controllers, and their relative importance. It discusses how FACTS controllers can control parameters like line impedance, phase angle, and voltage injection to regulate power flow. The key types of FACTS controllers are series, shunt, and combined series-series or series-shunt configurations. Series controllers directly impact current and power flow, while shunt controllers control voltage. Combined controllers allow coordinated control and real power transfer between elements.
This document discusses Flexible AC Transmission Systems (FACTS) controllers. It defines FACTS controllers as power electronic devices that control parameters of AC transmission systems. The document describes several types of FACTS controllers including STATCOM, SVC, TCSC, SSSC, and UPFC. It explains how each type of controller works and its benefits such as increasing power transfer capability and network reliability.
The electricity supply industry is undergoing a profound transformation worldwide. Market forces, scarcer natural resources, and an ever-increasing demand for electricity are some of the drivers responsible for such unprecedented change. Against this background of rapid evolution, the expansion programs of many utilities are being thwarted by a variety of well-founded, environment, land-use, and regulatory pressures that prevent the licensing and building of new transmission lines and electricity generating plants.
The document discusses the basic types of FACTS (Flexible AC Transmission System) controllers, including series controllers that inject voltage in series with a line, shunt controllers that inject current, and combined series-shunt controllers. FACTS controllers are used to control power flow and improve voltage profiles by injecting currents and voltages. The choice of controller depends on the desired control over current, power flow, damping of oscillations, and improvement of voltage.
Reactive power management and voltage control by using statcomHussain Ali
This document summarizes the use of STATCOM devices for reactive power management and voltage control in transmission lines. It defines reactive power and explains the need for reactive power compensation. It then defines FACTS devices and specifically STATCOMs, describing their basic structure and principle of operation for generating and absorbing reactive power. The document discusses how STATCOMs can provide benefits like reactive power control, voltage regulation, and increased transmission capacity. It provides an example of a 500 MVAR STATCOM installed between Qatar and Bahrain for reactive power compensation and concludes that STATCOMs allow tighter voltage control and improved reliability compared to traditional capacitor banks.
This document summarizes a seminar on reactive power compensation. It discusses the different types of power, including active power, reactive power, and apparent power. It explains that reactive power is needed by magnetic equipment like transformers and motors to produce magnetizing flux. The document outlines the need for reactive power compensation to improve power factor, reduce losses, increase capacity, and improve voltage regulation. It then describes different compensation techniques like shunt compensation using capacitors at the load, substation, or transmission level. The document also discusses synchronous condensers and power electronics devices like thyristor controlled reactors, static VAR compensators, and thyristor controlled series compensators for reactive power compensation.
A flexible alternating current transmission system (FACTS) is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system.
In conventional AC transmission system, the ability to transfer AC power is limited by several factors like thermal limits, transient stability limit, voltage limit, short circuit current limit etc. These limits define the maximum electric power which can be efficiently transmitted through the transmission line without causing any damage to the electrical equipments and the transmission lines. This is normally achieved by bringing changes in the power system layout. However this is not feasible and another way of achieving maximum power transfer capability without any changes in the power system layout. Also with the introduction of variable impedance devices like capacitors and inductors, whole of the energy or power from the source is not transferred to the load, but a part is stored in these devices as reactive power and returned back to the source. Thus the actual amount of power transferred to the load or the active power is always less than the apparent power or the net power. For ideal transmission the active power should be equal to the apparent power. In other words, the power factor (the ratio of active power to apparent power) should be unity. This is where the role of Flexible AC transmission System comes.
This document discusses power system security. It defines power system security as the probability of the system operating within acceptable ranges given potential changes or contingencies. It outlines the key steps in power system security including: (1) monitoring the current system state, (2) contingency analysis to evaluate potential risks, and (3) corrective action analysis to maintain security through preventative or automatic corrective actions.
In the modern power system the reactive power compensation is one of the main issues, the transmission of active power requires a difference in angular phase between voltages at the sending and receiving points (which is feasible within wide limits), whereas the transmission of reactive power requires a difference in magnitude of these same voltages (which is feasible only within very narrow limits). The reactive power is consumed not only by most of the network elements, but also by most of the consumer loads, so it must be supplied somewhere. If we can't transmit it very easily, then it ought to be generated where it is needed." (Reference Edited by T. J. E. Miller, Forward Page ix).Thus we need to work on the efficient methods by which VAR compensation can be applied easily and we can optimize the modern power system. VAR control technique can provides appropriate placement of compensation devices by which a desirable voltage profile can be achieved and at the same time minimizing the power losses in the system. This report discusses the transmission line requirements for reactive power compensation. In this report thyristor switched capacitor is explained which is a static VAR compensator used for reactive power management in electrical systems.
Seminar Topic For Electrical and Electronics Engineering (EEE)
This document discusses different methods for generating high AC and impulse voltages for testing purposes. It describes cascade transformers which can produce voltages over 300kV by connecting multiple transformer units in series. It also covers Marx circuits which charge multiple capacitors in parallel and discharge them in series to achieve high impulse voltages. Switching surges with long durations can be created using a transformer excited by a DC voltage that produces damped oscillations.
This document discusses issues related to interconnecting microgrids. It describes how a DC microgrid system utilizes a DC bus to distribute power from photovoltaic units and battery storage to local households. Interconnection can be done directly through switchgear or power electronic interfaces. Key issues that can arise include voltage and frequency fluctuations that occur due to imbalance between supply and demand, power factor correction needs, and harmonics produced by some loads. Unintentional islanding is also a safety concern that must be addressed when connecting microgrids to the main power grid.
Design, Planning and Layout of high voltage laboratory vishalgohel12195
Design, Planning and Layout of high voltage laboratory
Test equipment provided in high voltage lab
Activity and study in high voltage lab
Classification of high voltage lab
Clearance of high voltage Lab
Layout of high voltage lab
Safety
Shielding of the high voltage lab
The UPFC is a FACTS device that can control all three parameters of line power flow - voltage, impedance, and phase angle. It consists of two voltage source inverters, one connected in series with the transmission line and one connected in shunt. The shunt inverter controls reactive power flow and voltage, while the series inverter controls real and reactive power flow by injecting a controllable voltage in series with the line. Control schemes for the UPFC include phase angle control, cross-coupling control, and a generalized control scheme that provides damping against power swings for improved stability. The UPFC offers benefits like improved power transfer capacity, transient stability, and independent control of real and reactive power flows.
This document presents a proposal for designing, simulating, and implementing a Unified Power Flow Controller (UPFC) for a power system model. The UPFC is introduced as a versatile Flexible AC Transmission Systems device that can control active and reactive power flow. The proposal outlines objectives to design and simulate a UPFC model in MATLAB/Simulink, implement the hardware, compare experimental and simulation results, and integrate the controllable UPFC into the university's power system model to improve power quality. A timeline is proposed from June 2016 to March 2017 to conduct background research, system design, simulation, hardware implementation, results analysis, and reporting.
Power Flow Control In A Transmission Line Using Unified Power Flow ControllerIJMER
This paper concentrates on FACT device UPFC which is used for powerflow control in the
transmission side. With the growing demand of electricity, it is not possible to erect new lines to face the
situation. Flexible AC Transmission System (FACTS) makes use of the thyristor controlled devices and optimally
utilizes the existing transmission network. One of such device is Unified Power Flow Controller (UPFC) on
which the emphasis is given in this present work. Real, reactive power, and voltage balance of the unified
power-flow control (UPFC) system is analyzed. A novel coordination controller is proposed for the UPFC.
The basic control method is such that the shunt converter controls the transmission line reactive power
flow and the dc-link voltage. The series converter controls the real power flow in the transmission line and
the UPFC bus voltages. Experimental works have been conducted to verify the effectiveness of the
UPFC in power flow control in the transmission line. The simulation model was done in
MATLAB/SIMULINK platform.
Flexible AC Transmission Systems (FACTS) use power electronics to control power flow and increase transmission capacity. FACTS devices include SVCs, TCSCs, TCPARs, StatComs, SSSCs, and UPFCs. A UPFC can control both voltage and impedance to regulate active and reactive power flow bidirectionally. It does this by generating reactive power with shunt inverters and injecting real power with series inverters using PWM to control voltages. This allows increasing transmission line capacity and controlling power flows.
Optimal Load flow control using UPFC methodNishant Kumar
One large-scale network have been presented. The UPFC model itself showed to be very flexible, it takes in to account the various UPFC operating modes.
UPFC is able to control active and reactive power flow in transmission line.
Implementation of UPFC for Improvement of Power StabilityIOSR Journals
This document presents a study on implementing a Unified Power Flow Controller (UPFC) to improve power stability in multi-machine power systems. Simulation models of power systems with and without UPFC are developed in MATLAB. A two hydro generating station system is analyzed under a 3-phase fault condition, showing oscillations in voltage, active power, and reactive power without UPFC. With UPFC installed, the oscillations are reduced and the fault clearing time is decreased. The UPFC provides simultaneous control of voltage, power flow, and impedance to enhance stability.
power factor correction using smart relayHatem Seoudy
This document summarizes active, reactive, and apparent power. It defines these three types of power and provides equations to calculate them for different load types, including resistive, reactive, and resistive/reactive loads. It explains power factor as the ratio of active power to apparent power and discusses causes of low power factor. Typical power factor values are provided for different load types. Improving power factor provides benefits like reduced electricity bills and equipment costs.
This document is a project report submitted by A.L. Mohamed Soofi on power factor improvement. It includes details such as the title, examiners, supervisor, and personnel details of the author. The abstract indicates that the report focuses on commonly used power factor correction methods in industries, particularly capacitor banks. It also acknowledges guidance from the project supervisor Prof. Dr. K Chandrabose of the Electrical Engineering Department at APSS Engineering City and guilds Approved centre.
Transient Stability of Power System using Facts Device-UPFCijsrd.com
This paper is based on Occurrence of a fault in a power system causes transients. To stabilize the system, The Flexible Alternating Current Transmission (FACTS) devices such as UPFC are becoming important in suppressing power system oscillations and improving system damping. The UPFC is a solid-state device, which can be used to control the active and reactive power.. By using a UPFC the oscillation introduced by the faults, the rotor angle and speed deviations can be damped out quickly than a system without a UPFC. The effectiveness of UPFC in suppressing power system oscillation is investigated by analyzing their oscillation in rotor angle and change in speed occurred in the two machine system considered in this work. A proportional integral (PI) controller has been employed for the UPFC. It is also shown that a UPFC can control independently the real and reactive power flow in a transmission line. A MATLAB simulation has been carried out to demonstrate the performance of the UPFC in achieving transient stability of the two-machine five-bus system.
This document compares the effectiveness of STATCOM, SSSC, and UPFC FACTS devices in improving power system stability. It presents a single machine infinite bus system model with each device and analyzes the response to a 3-phase fault. All FACTS devices reduce oscillations and stabilize the system after the fault, while the uncompensated system becomes unstable. STATCOM and SSSC effectively suppress oscillations and stabilize the rotor angle, velocity, and generator output power. UPFC combines features of STATCOM and SSSC to regulate real and reactive power flow and make the system stable.
There are two broad classes of power system stability:
1) Steady state stability - The ability of a system to maintain equilibrium after a small disturbance.
2) Transient stability - The ability to maintain synchronism during large disturbances like faults.
Factors influencing transient stability include generator loading, fault conditions, clearing time, reactances, and inertia. Methods to improve it include high-speed excitation, series capacitors, fault clearing and independent pole operation.
Injection of the wind power into an electric grid affects the power quality. The performance of the wind turbine and thereby power quality are determined on the basis of measurements and the norms followed according to the guideline specified in International Electro-technical Commission standard, IEC-61400. The influence of the wind turbine in the grid system concerning the power quality measurements are-the active power, reactive power, variation of voltage, flicker, harmonics, and electrical behavior of switching operation and these are measured according to national/international guidelines. The paper study demonstrates the power quality problem due to installation of wind turbine with the grid. In this proposed scheme STATic COMpensator (STATCOM) is connected at a point of common coupling with a battery energy storage system (BESS) to mitigate the power quality issues. The battery energy storage is integrated to sustain the real power source under fluctuating wind power. The STATCOM control scheme for the grid connected wind energy generation system for power quality improvement is simulated using MATLAB/SIMULINK in power system block set. The effectiveness of the proposed scheme relives the main supply source from the reactive power demand of the load and the induction generator. The development of the grid co-ordination rule and the scheme for improvement in power quality norms as per IEC-standard on the grid has been presented.
Power Quality is a combination of Voltage profile, Frequency profile, Harmonics contain and reliability of power supply.
The Power Quality is defined as the degree to which the power supply approaches the ideal case of stable, uninterrupted, zero distortion and disturbance free supply.
This document discusses power quality and defines it as the ability of a power system to supply voltage continuously within tolerances. It outlines various power quality events like sags, swells, interruptions, harmonics, and their causes and effects. It then describes various techniques to mitigate power quality issues, including dynamic voltage restorers, harmonic filters, static VAR compensators, and unified power quality conditioners. Maintaining high power quality improves system efficiency and equipment lifespan while eliminating problems like voltage fluctuations, harmonics, and reactive power issues.
This document is a thesis that presents a motor model and parameter measurement methods for use in a direct torque controlled (DTC) drive application for an electrically excited synchronous motor. A motor model combining voltage and current models is proposed to estimate flux linkages for DTC. Methods are described for initializing motor parameters from design data or measurements, and for performing an identification run using the inverter to measure key parameters like resistances and inductances. Experimental results demonstrate the static torque accuracy and dynamic performance achieved using the proposed motor model in a DTC drive.
Load flow analysis with upfc under unsymmetrical fault conditionAlexander Decker
This document discusses load flow analysis with and without a Unified Power Flow Controller (UPFC) under different fault conditions in a six bus power system simulation model. The UPFC is a Flexible AC Transmission System (FACTS) device that can control parameters like voltage, impedance, and phase angle to control power flow. The study aims to improve transient stability of the six bus system by determining active and reactive power on load buses under different fault types both with and without the UPFC. The control scheme and operating principle of the UPFC are also explained.
POWER FACTOR CORRECTION OF A 3-PHASE 4- SWITCH INVERTER FED BLDC MOTORvanmukil
This document provides an overview of brushless DC motors. It discusses their construction, operation, and applications. Key points include:
- BLDC motors have electronic commutation rather than mechanical brushes. They provide linear torque-speed characteristics like brushed DC motors.
- They consist of a radially magnetized permanent magnet rotor and phase windings on the stator. Electronic controllers and position sensors enable synchronized commutation.
- BLDC motors are widely used in applications like computers, appliances, electric vehicles due to their reliability, efficiency and power density compared to brushed DC motors.
- The document reviews BLDC motor components, control methods, torque production principles and common configurations like three-phase
This document summarizes a research paper that analyzes the performance of a 3-level space vector pulse width modulation (SVPWM) controlled unified power flow controller (UPFC) placed at different locations in an IEEE 14 bus system under a line-to-ground fault. The UPFC combines a static synchronous compensator (STATCOM) and static synchronous series compensator (SSSC) to independently control voltage, real and reactive power flow. Simulation results using MATLAB/Simulink show that a 3-level SVPWM control strategy effectively compensates for problems related to reactive power and power quality under unbalanced fault conditions.
Power quality improvement in a weak bus system using facts controllereSAT Journals
Abstract Power quality management is the main problem that the industry is facing today. This is mainly affected by the generation of harmonics. The growing use of electronic equipment produces a large amount of harmonics in distribution systems because of non-sinusoidal currents consumed by non-linear loads. As we know for the better quality of power, the voltage and current waveforms should be sinusoidal, but in actual practice it is somewhat disturbed and this phenomenon is called “Harmonic Distortion”. Voltage harmonics are generally present in supply of power from utility. Even though electronic and non-linear devices are flexible, economical and energy efficient, they may degrade power quality by creating harmonic currents and consuming excessive reactive power. The STATCOM as FACTS controller can be applied to a single non-linear load or many. It provides controlled current injection to remove harmonic current from the source side of electric system and also can improve the power factor. Keywords-: Controller design, PI Controller, FACTS and STATCOM.
This document analyzes the performance of Z-source inverter (ZSI) based unified power flow controller (UPFC) compared to voltage source inverter (VSI) based UPFC in a transmission system under three-phase fault conditions. Simulation models are developed for cases with and without UPFC, and with VSI-UPFC and ZSI-UPFC. The results show that fault current and I2R losses are reduced more with ZSI-UPFC than with VSI-UPFC or without UPFC. Therefore, the performance of ZSI-based UPFC is determined to be superior for mitigating faults in transmission systems.
This document summarizes a research paper that proposes a FACTS-based Static Switched Filter Compensator (SSFC) scheme for improving power quality when integrating wind energy into smart grids. The SSFC scheme uses controlled switching between two capacitor banks to provide series and shunt compensation. It is controlled using a tri-loop dynamic error controller and VSC controller to mitigate harmonics, stabilize voltages, improve power factor, and reduce losses. Simulation results using Matlab/Simulink show the SSFC scheme improves voltage regulation, reduces current and voltage harmonics to within IEEE limits, and enhances the power factor at generator, load and grid buses compared to without SSFC.
This document provides a review of the Unified Power Flow Controller (UPFC), a type of Flexible AC Transmission System (FACTS) device. It discusses the basic components and operating principles of the UPFC, which combines the functions of a STATCOM and SSSC to control active and reactive power flow. The UPFC consists of two voltage source converters connected back-to-back via a DC link. One converter injects a voltage in series with the transmission line to control power flow while the other exchanges reactive power with the line to regulate the DC link voltage. Control schemes for both converters are described. The document also presents Simulink models of the UPFC and concludes it is effective for improving power system stability
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A Review on Optimization Techniques for Power Quality Improvement using DSTAT...ijtsrd
This document summarizes a research paper that proposes using a neural network approach to optimize techniques for improving power quality using a DSTATCOM (Distribution Static Compensator). It begins by introducing common power quality issues like voltage sags, swells, and harmonics. It then discusses different custom power devices used to address these issues, focusing on the DSTATCOM. The paper proposes a control algorithm using a backpropagation neural network to extract reference currents and control the DSTATCOM for reactive power compensation, load balancing, and voltage regulation. Simulation results showed the DSTATCOM was able to satisfactorily compensate for different types of loads using this neural network approach.
power quality improvement of power system network using UPFCBikash Gyawali
This document presents a project on improving power quality in a power system network using a Unified Power Flow Controller (UPFC). It defines power quality and discusses causes of poor power quality such as non-linear loads and switching operations. It then introduces Flexible AC Transmission Systems (FACTS) devices as a way to improve power quality and lists benefits such as increasing power transfer capability and improving transient stability. Specifically, it describes a UPFC, which combines a static synchronous compensator (STATCOM) and static synchronous series compensator (SSSC) to independently control real and reactive power flow. The UPFC configuration and components are shown, and it is explained how the UPFC can improve power quality by regulating voltage, impedance
This document summarizes several FACTS (Flexible AC Transmission Systems) devices that can be installed in power systems to better control power flows. It discusses both shunt and series FACTS controllers, including the Static VAR Compensator (SVC), Thyristor Controlled Series Capacitor (TCSC), Thyristor Controlled Phase Angle Regulator (TCPAR), Static Synchronous Compensator (STATCOM), Static Synchronous Series Compensator (SSSC), Unified Power Flow Controller (UPFC), Interline Power Flow Controller (IPFC) and others. It provides an overview of how these devices work and their benefits, such as increasing transmission capacity, improving stability, and allowing for more optimal
Optimization Technique for Power Quality Improvement using DSTATCOM Neural Ne...ijtsrd
This document reviews optimization techniques for power quality improvement using DSTATCOM with a neural network approach. It discusses how DSTATCOM and other custom power devices like DVR, UPQC can be used to improve power quality by mitigating issues like voltage sags, swells, harmonics, and reactive power. It also presents the configuration of a DSTATCOM system and a control algorithm using a backpropagation neural network to extract fundamental active and reactive power components and estimate harmonic currents for compensation under nonlinear loads. The proposed neural network control approach for DSTATCOM is aimed to improve power quality by compensating for harmonics, reactive power, and providing zero voltage regulation.
This document discusses power quality enhancement using Flexible AC Transmission System (FACTS) devices. It provides an overview of various FACTS devices including Static Var Compensator (SVC), Static Synchronous Compensator (STATCOM), and Static Synchronous Series Compensator (SSSC). MATLAB simulations of systems using SVC, STATCOM and SSSC are presented to demonstrate how each FACTS device can improve power quality by mitigating issues like voltage fluctuations and power oscillations. The document concludes that FACTS devices provide better power quality under varying source voltages and sudden loading conditions.
International Journal of Engineering Research and DevelopmentIJERD Editor
This document discusses power quality enhancement using Flexible AC Transmission System (FACTS) devices. It provides an overview of various FACTS devices including Static Var Compensator (SVC), Static Synchronous Compensator (STATCOM), and Static Synchronous Series Compensator (SSSC). MATLAB simulations of systems using SVC, STATCOM and SSSC are presented to demonstrate how each FACTS device can improve power quality by mitigating issues like voltage fluctuations and power oscillations. The document concludes that FACTS devices provide better power quality under varying source voltages and sudden loading conditions.
This presentation provides an overview of Flexible AC Transmission Systems (FACTS) devices. It defines FACTS as power electronics-based static equipment used to improve power transfer capability and enhance controllability of AC transmission systems. The presentation categorizes FACTS devices based on their connection type to the transmission network and technology. It describes common first and second generation FACTS devices such as SVC, STATCOM, SSSC, TCSC, and UPFC; and their technical benefits regarding load flow control, voltage control, and stability. Potential applications and future enhancements of FACTS are also discussed, along with benefits, operation, and maintenance.
International Refereed Journal of Engineering and Science (IRJES) is a peer reviewed online journal for professionals and researchers in the field of computer science. The main aim is to resolve emerging and outstanding problems revealed by recent social and technological change. IJRES provides the platform for the researchers to present and evaluate their work from both theoretical and technical aspects and to share their views.
www.irjes.com
IRJET- Optimization of Loss Reduction using FACTS Device (SVC & STATCOM) ...IRJET Journal
This document discusses optimization of power losses in extra high voltage transmission systems using Flexible AC Transmission System (FACTS) devices like SVC and STATCOM. It analyzes power losses that occur due to line resistance and current flow. FACTS devices can control parameters like line reactance to reduce losses and enhance power transfer capability. The study models and simulates placement of TCSC FACTS devices on IEEE 9-bus, 14-bus and 30-bus test systems. Results show TCSC placement reduces total real power losses by 6.7-17% depending on the test system. Optimal TCSC location is determined as the line with maximum power losses.
Application of Multilevel Voltage-Source-Converter in FACTS Devices for Power...IJMER
This document discusses a study on applying a multilevel voltage-source converter (VSC) in flexible AC transmission systems (FACTS) devices for power system voltage control and reactive power compensation. Specifically, it proposes a sixty pulse VSC STATCOM design that combines a twelve pulse converter with a five-level voltage source inverter (VSI) to improve performance. The study finds that the multilevel VSI STATCOM is able to provide satisfactory reactive power flow control and respond quickly to changes in reactive current reference. THD is also maintained within acceptable limits. FACTS devices using power electronics, such as STATCOMs, help enhance power transfer capability, flexibility and stability in transmission networks.
A New approach for controlling the power flow in a transmission system using ...IJMER
Electrical power systems is a large interconnected network that requires a careful design to maintain the system with continuous power flow operation without any limitation. Flexible Alternating Current Transmission System (FACTS) is an application of a power electronics device to control the power flow and to improve the system stability of a power system. Unified Power Flow Controller (UPFC) is a new concept for the compensation and effective power flow control in a transmission system.Through common DC link, any inverters within the UPFC is able to transfer real power to any other and there by facilitate real power transfer among the line. In this paper a test system is simulated in MATLAB/SIMULINK and the results of the network with and without UPFC are compared and when the voltage sag is compensated, reactive power is controlled and transmission line efficiency is improved.
The document provides an overview of flexible AC transmission systems (FACTS) controllers. It discusses that FACTS controllers use power electronics to control parameters like impedance, voltage, and phase angle to enhance power flow controllability and transmission capacity. FACTS devices allow for better utilization of existing transmission systems and include series controllers that inject voltage in series with transmission lines and shunt controllers that inject current. The benefits of FACTS are more efficient power transfer, increased reliability and grid stability, and delayed investment in new transmission infrastructure.
IRJET- Improving Power Quality by using MC-UPQCIRJET Journal
This document discusses improving power quality by using a Multiconverter Unified Power Quality Conditioner (MC-UPQC). The MC-UPQC consists of one shunt voltage-source converter (VSC) and two or more series VSCs. It can be applied to adjacent feeders to simultaneously compensate for supply voltage imperfections and load current imperfections on the main feeder, as well as fully compensate supply voltage imperfections on other feeders. The converters are connected back-to-back on the DC side and share a common DC link capacitor, allowing power transfer between feeders. This configuration can compensate for sags/swells and interruptions in both feeders without battery storage. Simulation results will illustrate the performance
Flexible alternating current transmission systems (FACTs) technology opens up new opportunities for
controlling power flow and enhancing the usable capacity of present, as well as new and upgraded lines. These
FACTs device which enables independent control of active and reactive power besides improving reliability and
quality of the supply. This paper describes the real and reactive power flow control through a short transmission
line and then compensated short transmission line with different FACTs devices are used to selection of FACTs
devices for better reactive power compensation with change in line capacitance/shunt capacitance to observe
power flow. Computer simulation by MATLAB/SIMULINK has been used to determining better reactive power.
TCSC, STATCOM, UPFC and SSSC FACTs controller with different capacitance are tested for controlling
reactive power flow.
A Power quality problem is an occurrence of nonstandard voltage, current or frequency that results in a
failure or a misoperation of end user equipments. Utility distribution networks, sensitive industrial loads and
critical commercial operations suffer from various types of outages and service interruptions which can cost
significant financial losses. With the increase in load demand, the Renewable Energy Sources (RES) are
increasingly connected in the distribution systems which utilizes power electronic Converters/Inverters. This
paper presents a single-stage, three-phase grid connected solar photovoltaic (SPV) system. The proposed system
is dual purpose, as it not only feeds extracted solar energy into the grid but it also helps in improving power
quality in the distribution system. The presented system serves the purpose of maximum power point tracking
(MPPT), feeding SPV energy to the grid, harmonics mitigation of loads connected at point of common coupling
(PCC) and balancing the grid currents. The SPV system uses a three-phase voltage source converter (VSC) for
performing all these functions. An improved linear sinusoidal tracer (ILST)-based control algorithm is proposed
for control of VSC. In the proposed system, a variable dc link voltage is used for MPPT. An instantaneous
compensation technique is used incorporating changes in PV power for fast dynamic response. The SPV system
is first simulated in MATLAB along with Simulink and simpower system toolboxes.
IRJET- Enhancement of Power Flow Capability in Power System using UPFC- A RevieWIRJET Journal
This document reviews the use of a Unified Power Flow Controller (UPFC) to enhance power flow capability in power systems. The UPFC is a flexible AC transmission system (FACTS) device that can control both real and reactive power flows on a transmission line. It consists of two voltage source converters connected by a DC link: a static synchronous compensator (STATCOM) and a static synchronous series compensator (SSSC). The STATCOM controls reactive power and the DC link voltage, while the SSSC injects a controlled AC voltage in series with the transmission line to vary the transmission line impedance and power flow. Simulation results show that a UPFC installed on the IEEE 5 bus test system can control power flows and
Similar to Power factor improvement using upfc (20)
TEACHING AND LEARNING BASED OPTIMISATIONUday Wankar
Teaching–Learning-Based Optimization (TLBO) seems to be a rising star from amongst a number of metaheuristics with relatively competitive performances. It is reported that it outperforms some of the well-known metaheuristics regarding constrained benchmark functions, constrained mechanical design, and continuous non-linear numerical optimization problems. Such a breakthrough has steered us towards investigating the secrets of TLBO’s dominance. This report’s findings on TLBO qualitatively and quantitatively through code-reviews and experiments, respectively.
It is a selection of best element (with regard to some criteria) from some set of available alternatives. In the simplest case, an optimization problem consist of maximizing or minimizing a real function by choosing input values from within an allowed set and computing the value of function. The classical optimization techniques are useful in finding the optimum solution or unconstrained maxima or minima of continuous and differentiable functions. These are analytical methods and make use of differential calculus in locating the optimum solution. The classical methods have limited scope in practical applications as some of them involve objective functions which are not continuous and un-differentiable. Yet, the study of these classical techniques of optimization form a basis for developing most of the numerical techniques that have evolved into advanced techniques more suitable to today’s practical problems.
The shuffled frog leaping algorithm is an evolutionary algorithm inspired by the behavior of frogs searching for food. It works by first randomly generating a population of solutions and dividing them into groups. Each group conducts a local search, and the best solutions are shared among groups in shuffling processes. This continues until a convergence threshold is reached. The algorithm has applications in optimization problems like power grid design, construction scheduling, and water network planning by evaluating many potential solutions efficiently.
For three decades, many mathematical programming methods have been developed to solve optimization problems. However, until now, there has not been a single totally efficient and robust method to coverall optimization problems that arise in the different engineering fields.Most engineering application design problems involve the choice of design variable values that better describe the behaviour of a system.At the same time, those results should cover the requirements and specifications imposed by the norms for that system. This last condition leads to predicting what the entrance parameter values should be whose design results comply with the norms and also present good performance, which describes the inverse problem.Generally, in design problems the variables are discreet from the mathematical point of view. However, most mathematical optimization applications are focused and developed for continuous variables. Presently, there are many research articles about optimization methods; the typical ones are based on calculus,numerical methods, and random methods.
The calculus-based methods have been intensely studied and are subdivided in two main classes: 1) the direct search methods find a local maximum moving a function over the relative local gradient directions and 2) the indirect methods usually find the local ends solving a set of non-linear equations, resultant of equating the gradient from the object function to zero, i.e., by means of multidimensional generalization of the notion of the function’s extreme points from elementary calculus given smooth function without restrictions to find a possible maximum which is to be restricted to those points whose slope is zero in all directions. The real world has many discontinuities and noisy spaces, which is why it is not surprising that the methods depending upon the restrictive requirements of continuity and existence of a derivative, are unsuitable for all, but a very limited problem domain. A number of schemes have been applied in many forms and sizes. The idea is quite direct inside a finite search space or a discrete infinite search space, where the algorithms can locate the object function values in each space point one at a time. The simplicity of this kind of algorithm is very attractive when the numbers of possibilities are very small. Nevertheless, these outlines are often inefficient, since they do not complete the requirements of robustness in big or highly-dimensional spaces, making it quite a hard task to find the optimal values. Given the shortcomings of the calculus-based techniques and the numerical ones the random methods have increased their popularity.
Finding an alternative with the most cost effective or highest achievable performance under the given constraints, by maximizing desired factors and minimizing undesired ones. It also mean that it make best use of a situation or resource. In comparison, maximization means trying to attain the highest or maximum result or outcome without regard to cost or expense. Practice of optimization is restricted by the lack of full information, and the lack of time to evaluate what information is available (see bounded reality for details). In computer simulation (modeling) of business problems, optimization is achieved usually by using linear programming techniques of operations research.
The first ant colony optimization (ACO) called ant system was inspired through studying of the behaviour of ants in 1991 by Macro Dorigo and co-workers. An ant colony is highly organized, in which one interacting with others through pheromone in perfect harmony. Optimization problems can be solved through simulating ant’s behaviours. Since the first ant system algorithm was proposed, there is a lot of development in ACO. In ant colony system algorithm, local pheromone is used for ants to search optimum result. However, high magnitude of computing is its deficiency and sometimes it is inefficient. Thomas Stützle etal. Introduced MAX-MIN Ant System (MMAS) in 2000. It is one of the best algorithms of ACO. It limits total pheromone in every trip or sub-union to avoid local convergence. However, the limitation of pheromone slows down convergence rate in MMAS.
The gas turbine is an internal combustion engine that uses air as the working fluid. The engine extracts chemical energy from fuel and converts it to mechanical energy using the gaseous energy of the working fluid (air) to drive the engine and propeller, which, in turn, propel the aeroplane.
The gas turbine is an internal combustion engine that uses air as the working fluid. The engine extracts chemical energy from fuel and converts it to mechanical energy using the gaseous energy of the working fluid (air) to drive the engine and propeller, which, in turn, propel the airplane.
This ppt show the steps to rewind the Brushless motor(BLDC)
If you fly brushless you've probably cooked a motor or two. You also probably know there are many different types of motors. Similar motors when wound differently performs very differently. Whether you've burned the motor up, or just want to alter performance, rewinding is a cheap solution for a patient modeller.
For this tutorial, I will be using Dynam E-Razor 450 Brushless Motor 60P-DYM-0011 (2750Kv). It is a Delta wound 8T (It means 8 turns ) quad wind.
The winding pattern described in this tutorial (called an ABC wind - ABCABCABC as you go around the stator) works for any brushless motor with 9 stator teeth and 6 magnets.
This ppt show the steps to rewind the Brushless motor(BLDC)
If you fly brushless you've probably cooked a motor or two. You also probably know there are many different types of motors. Similar motors when wound differently performs very differently. Whether you've burned the motor up, or just want to alter performance, rewinding is a cheap solution for a patient modeller.
For this tutorial, I will be using Dynam E-Razor 450 Brushless Motor 60P-DYM-0011 (2750Kv). It is a Delta wound 8T (It means 8 turns ) quad wind.
The winding pattern described in this tutorial (called an ABC wind - ABCABCABC as you go around the stator) works for any brushless motor with 9 stator teeth and 6 magnets.
Our project is a persistence of vision display (POV) that spins 360 degrees horizontally. The purpose of our POV display project is to create a small apparatus that will create a visual using only a small number of LEDs as it spins in a circle. When the LEDs rotate several times around a point in less than a second, the human eye reaches its limit of motion perception and creates an illusion of a continuous image. Therefore, our POV display demonstrates this phenomenon by creating a visual as the LEDs spin rapidly in a circle and the person watching will see one continuous image.
Arm cortex (lpc 2148) based motor speedUday Wankar
The project is designed to control the speed of a DC and AC motor using an
ARM7 LPC2148 processor. The speed of motor is directly proportional to the voltage
applied across its terminals. Hence, if voltage across motor terminal is varied, then
speed can also be varied. This project uses the above principle to control the speed of
the motor by varying the duty cycle of the pulses applied to it, popularly known as
PWM control. The project uses input button interfaced to the processor, which are
used to control the speed of motor. Pulse Width Modulation is generated at the output
by the microcontroller as per the program. The program is written in Embedded C.
The average voltage given or the average current flowing through the motor
will change depending on the duty cycle, ON and OFF time of the pulses, so the speed
of the motor will change. A motor driver IC is interfaced to the ARM7 LPC2148
processor board for receiving PWM signals and delivering desired output for speed
control. Further the project can be enhanced by using power electronic devices such
as IGBTs to achieve speed control higher capacity industrial motors.
Arm Processor Based Speed Control Of BLDC MotorUday Wankar
The project is designed to control the speed of a DC motor using an ARM series processor. The speed of DC motor is directly proportional to the voltage applied across its terminals. Hence, if voltage across motor terminal is varied, then speed can also be varied. This project uses the above principle to control the speed of the motor by varying the duty cycle of the pulse applied to it (popularly known as PWM control). The project uses input button interfaced to the processor, which are used to control the speed of motor. PWM (Pulse Width Modulation) is generated at the output by the microcontroller as per the program. The program is written in Embedded C. The average voltage given or the average current flowing through the motor will change depending on the duty cycle (ON and OFF time of the pulses), so the speed of the motor will change. A motor driver IC is interfaced to the STM32 board for receiving PWM signals and delivering desired output for speed control of a small DC motor. Further the project can be enhanced by using power electronic devices such as IGBTs to achieve speed control higher capacity industrial motors.
Arm cortex ( lpc 2148 ) based motor speed control Uday Wankar
The project is designed to control the speed of a DC and AC motor using an ARM7 LPC2148 processor. The speed of motor is directly proportional to the voltage applied across its terminals. Hence, if voltage across motor terminal is varied, then speed can also be varied. This project uses the above principle to control the speed of the motor by varying the duty cycle of the pulses applied to it, popularly known as PWM control. The project uses input button interfaced to the processor, which are used to control the speed of motor. Pulse Width Modulation is generated at the output by the microcontroller as per the program. The program is written in Embedded C.
The average voltage given or the average current flowing through the motor will change depending on the duty cycle, ON and OFF time of the pulses, so the speed of the motor will change. A motor driver IC is interfaced to the ARM7 LPC2148 processor board for receiving PWM signals and delivering desired output for speed control. Further the project can be enhanced by using power electronic devices such as IGBTs to achieve speed control higher capacity industrial motors.
Arm cortex ( lpc 2148 ) based motor speed control Uday Wankar
This document describes a project to control the speed of DC and AC motors using an ARM7 LPC2148 microcontroller. It uses pulse width modulation (PWM) signals from the microcontroller and motor driver circuits to vary the duty cycle and average voltage applied to the motors, allowing control of motor speed. The hardware used includes an LPC2148 board, LCD, control switches, L293D DC motor driver, optocoupler, TRIAC, and snubber circuit for the AC motor. The project successfully demonstrates controlling motor speed by varying the PWM duty cycle from 30% to 90%.
MSEB was set up in 1960 to generate, transmit and distribute power to all consumers in
Maharashtra excluding Mumbai. MSEB was the largest SEB in the country. The generation
capacity of MSEB has grown from 760 MW in 1960-61 to 9771 MW in 2001-02. The customer
base has grown from 1,07,833 in 1960-61 to 1,40,09,089 in 2001-02.
C.S.T.P.S in contribution much in field of production of electricity. It is not only number
one thermal power station in Asia but also has occupied specific position on the international
map.
The first set was commission on August 1983 & was dedicated to nation by then PM
(late) Mrs. Indira Gandhi & second set commission on July 1984. The third & fourth units of
CSTPS under stage 2 were commissioned on the 3rd May 1985 & 8th March 1986 respectively.
The units 5 & 6 were commissioned on the 22nd March 1991 & 11th March 1992 respectively one
more units of 500MW was added to the CSTPS on making its generation to 2340 MW &
making “C.S.T.P.S.” as the giant in Power Generation of CSTPS.
With the development of industry and
agriculture, a great amount of energy such as coal, oil
and gas has been consumed in the world. Extensive
use of these fossil energies deteriorates a series of
problems like energy crisis, environmental pollution
and so on. Everybody knows that the fossil energy
reserves are finite, some day it will be exhausted.
It is possible that the world will face a
global energy crisis due to a decline in the
availability of cheap oil and recommendations to a
decreasing dependency on fossil fuel. This has led to
increasing interest in alternate power/fuel research
such as fuel cell technology, hydrogen fuel, biodiesel,
Karrick process, solar energy, geothermal energy,
tidal energy and wind. Today, solar energy and wind
energy have significantly alternated fossil fuel with
big ecological problems.
With the development of the science and
technology, power generation using solar energy and
wind power is gradually known by more and more
people. And it is widespread used in many developed
countries. The merits of the solar and wind power
generation are very obvious-infinite and nonpolluting.
The raw materials of the solar and wind
power generation derived from nature, and wind
power generation can work twenty-four hours a day,
solar power generation only works by daylight. In
addition, this kind of power generation has no
exhaust emission and there is no influence to the
nature. But it also has some shortcomings. Because
of the imperfect of the technology, equipment of the
solar and wind power generation is very expensive.
By far, it cannot be widely used.
In addition, solar and wind power
generation system affected by the changing of the
weather very much, so it has obvious defects in
reliability compared with fossil fuel, and it is difficult
to make it fit for practical use the lack of economical
efficiency .Because of these problems it needs to
increase the reliability of energy supply by
developing a system which interacts Solar and wind
energy. This kind of system is usually called windsolar
hybrid power generation system significantly
Hybrid power generation by and solar –windUday Wankar
With the development of industry and
agriculture, a great amount of energy such as coal, oil
and gas has been consumed in the world. Extensive
use of these fossil energies deteriorates a series of
problems like energy crisis, environmental pollution
and so on. Everybody knows that the fossil energy
reserves are finite, some day it will be exhausted.
It is possible that the world will face a
global energy crisis due to a decline in the
availability of cheap oil and recommendations to a
decreasing dependency on fossil fuel. This has led to
increasing interest in alternate power/fuel research
such as fuel cell technology, hydrogen fuel, biodiesel,
Karrick process, solar energy, geothermal energy,
tidal energy and wind. Today, solar energy and wind
energy have significantly alternated fossil fuel with
big ecological problems.
With the development of the science and
technology, power generation using solar energy and
wind power is gradually known by more and more
people. And it is widespread used in many developed
countries. The merits of the solar and wind power
generation are very obvious-infinite and nonpolluting.
The raw materials of the solar and wind
power generation derived from nature, and wind
power generation can work twenty-four hours a day,
solar power generation only works by daylight. In
addition, this kind of power generation has no
exhaust emission and there is no influence to the
nature. But it also has some shortcomings. Because
of the imperfect of the technology, equipment of the
solar and wind power generation is very expensive.
By far, it cannot be widely used.
In addition, solar and wind power
generation system affected by the changing of the
weather very much, so it has obvious defects in
reliability compared with fossil fuel, and it is difficult
to make it fit for practical use the lack of economical
efficiency .Because of these problems it needs to
increase the reliability of energy supply by
developing a system which interacts Solar and wind
energy. This kind of system is usually called windsolar
hybrid power generation system significantly
This paper presents Grid Solver Bot which is a self-driven vehicle capable of localizing itself in a grid and planning a path between two nodes. It can avoid particular nodes and plan path between two allowed nodes. Breadth-first search & Dijkstra's Algorithm have been used for finding the path between two allowed nodes. The searching of a block over grid is easier when the rows and columns i.e. m* n of a grid is fixed. But when the grid is dynamic or changes over time than in such situation we require a generalized algorithm for traversing over a grid. In these paper we develop an approach for searching an object and also able to avoid an obstacle which was placed in a junction (meeting point of row and column). Here, we use different algorithms like Dijkistra’s, Best first search and A star algorithms. We develop an approach to find the block with minimum shortest path with the help of priority based algorithm. The vehicle is also capable of transferring blocks from one node to another. In fact, this vehicle is a prototype of a self-driven vehicle capable of transporting passengers and it can also be used in industries to transfer different items from one place to another.
Ballarpur Industries Limited (BILT) is a flagship of the US$ 4 bnAvantha Group and India's
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BILT's subsidiaries include Sabah Forest Industries (SFI), Malaysia's largest pulp and paper
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BILT’s acquisition of SFI in 2007 was a watershed event – it was the first overseas acquisition
by an Indian paper company. This acquisition transformed BILT into a major regional
player, and elevated the company's ranking among the global top 100.
Sachpazis_Consolidation Settlement Calculation Program-The Python Code and th...Dr.Costas Sachpazis
Consolidation Settlement Calculation Program-The Python Code
By Professor Dr. Costas Sachpazis, Civil Engineer & Geologist
This program calculates the consolidation settlement for a foundation based on soil layer properties and foundation data. It allows users to input multiple soil layers and foundation characteristics to determine the total settlement.
This is an overview of my current metallic design and engineering knowledge base built up over my professional career and two MSc degrees : - MSc in Advanced Manufacturing Technology University of Portsmouth graduated 1st May 1998, and MSc in Aircraft Engineering Cranfield University graduated 8th June 2007.
Better Builder Magazine brings together premium product manufactures and leading builders to create better differentiated homes and buildings that use less energy, save water and reduce our impact on the environment. The magazine is published four times a year.
Cricket management system ptoject report.pdfKamal Acharya
The aim of this project is to provide the complete information of the National and
International statistics. The information is available country wise and player wise. By
entering the data of eachmatch, we can get all type of reports instantly, which will be
useful to call back history of each player. Also the team performance in each match can
be obtained. We can get a report on number of matches, wins and lost.
Covid Management System Project Report.pdfKamal Acharya
CoVID-19 sprang up in Wuhan China in November 2019 and was declared a pandemic by the in January 2020 World Health Organization (WHO). Like the Spanish flu of 1918 that claimed millions of lives, the COVID-19 has caused the demise of thousands with China, Italy, Spain, USA and India having the highest statistics on infection and mortality rates. Regardless of existing sophisticated technologies and medical science, the spread has continued to surge high. With this COVID-19 Management System, organizations can respond virtually to the COVID-19 pandemic and protect, educate and care for citizens in the community in a quick and effective manner. This comprehensive solution not only helps in containing the virus but also proactively empowers both citizens and care providers to minimize the spread of the virus through targeted strategies and education.
2. iii
INDEX
SR.NO. CHAPTER PAGE NO.
1 Introduction 1
2 Flexible Ac Power Transmission System (Facts) 2
2.1 Objectives Of Facts Controller 4
2.2 Basic Types Of Facts Controller 4
2.2.1 Shunt Controller 6
2.2.2 Combined Series-Series Controller 6
2.2.3 Combined Series Shunt Controller 7
2.3 Benefits Of Facts Controller 7
3 Basic Principle Of UPFC 8
3.1 Operating Modes Of UPFC 9
3.1.1 Shunt Inverter 11
3.1.2 Series Inverter 13
3.2 Description Of Single Line Diagram 14
3.3 Static Compensator 15
3.4 Static Synchronous Series Compensator 16
3.5 Disadvantages 17
4 Application 18
5 Conclusion 19
References 20
3. iv
FIG NO. NAME OF FIGURE PAGE NO
2.1 Uncorrected SMPS Voltage And Current Waveform 3
2.2 Basic Types Of Facts Controller 5
3.1 Schematic Diagram Of UPFC 8
3.2 Vector Representation Of UPFC 11
3.3 UPFC Installed In Transmission Line 12
3.4 Single Line Diagram Of 500 KV / 230kv Transmission
System Using UPFC
14
3.5 Unified Power Flow Controller 15
3.6 Static Compensator(STATCOM) 16
3.7 Schematic Diagram Of SSSC 17
4. v
CHAPTER 1
INTRODUCTION
The significance of power factor correction (PFC) has long been visualized as
a technology requirement for improving the efficiency of a power system network by
compensating for the fundamental reactive power generated or consumed by simple
inductive or capacitive loads. With the Information Age in full swing, the growth of
high reliability, low cost electronic products have led utilities to escalate their power
quality concerns created by the increase of such “switching loads.” These products
include: entertainment devices such as Digital TVs, DVDs, and audio equipment;
information technology devices such as PCs, printers, and fax-machines; variable
speed motor drives for HVAC and white goods appliances; food preparation and
cooking products such as microwaves and cook tops; and lighting products, which
include electronic ballasts, LED and fluorescent lamps, and other power conversion
devices that operate a variety of lamps. The drivers that have resulted in this
proliferation are a direct result of the availability of low-cost switch-mode devices and
control circuitry in all major end-use segments: residential, commercial, and
industrial.
In order to keep power quality under the limits proposed by standards, it is
required to incorporate some sort of compensation. There are two basic types of PFC
circuits: active and passive. The simplest power factor correctors can be implemented
using a passive filter to suppress the harmonics in conjunction with capacitors or
inductors to generate or consume the fundamental reactive power, respectively.
Active power factor correction circuits have proven to be more effective, generally
integrated with the switch-mode circuitry, and actively control the input current of the
load. This enables the most efficient delivery of electrical power from the power grid
to the load. The demand for new smart, green products has set the stage for a
worldwide migration from antiquated passive circuits to active correctors as well as
from traditional analog technology to digital techniques. New digital active power
factor correction delivers better full- and light-load power efficiency while lowering
system costs, enabling smaller designs and providing a clear path for further feature
enhancements and improved competitive positioning for a whole host of consumer
and industrial products. Cirrus Logic’s novel advances in digital active PFC
5. vi
technology signify a major enabling element in the development of the newest generation of
low cost, energy-efficient switch mode products.
CHAPTER 2
FLEXIBLE AC TRANSMISSION SYSTEM (FACTS)
Power Factor (PF) is one of the first concepts introduced in a basic course on AC
circuit theory. Despite its apparent simplicity, it is frequently misunderstood and misapplied
due to misconceptions about the fundamental definition. The growing level of harmonic
currents generated by modern electronic devices has prompted government and industry to
look closer at the link between poor PF and harmonics created by “switching loads”. Power
factor is traditionally defined as the phase difference or displacement angle between
sinusoidal voltage and current waveforms created by linear loads (i.e. simple resistive and
reactive loads). When the AC load is partly capacitive or inductive, the current waveform is
out of phase with the voltage requiring additional AC current to be generated that is not
consumed by the load. These electrical losses (I2R) are consumed by the power delivery
system, e.g. power cables, transformers, etc. If the AC load is non-linear (i.e. current does not
very smoothly with voltage as in “switching loads”), the complex waveform’s PF is resolved
into fundamental frequency and its harmonics. Switching mode power supplies (SMPS) are a
good example onion-linear loads. SMPS conducts current in short pulses that are in phase
with the line voltage but is not a pure sine wave creating line harmonics.
These harmonic currents do not contribute to the load power. ENERGY STAR
Version 2.0 for External Power Supply defines true power factor as the ratio of the active, or
real, power (P) consumed in watts to the apparent power (S), drawn in volt-amperes (VA).
This definition of power factor includes the effect of both distortion and Displacement
Power factor correction (PFC) is a feature designed into the pulse width modulation (PWM)
controller to help regulate, stabilize, and provide the requirements for higher load current and
instantaneous current. The ideal objective for PFC is to drive the power factor as close to
unity as possible, making the load circuitry power factor corrected and the apparent power
equal to the real power. An effective power electronic circuit that controls the amount of
power drawn by a load in order to sustain a power factor as close as possible to unity is an
active PFC. Active PFC circuits control the load current in addition to shaping the input-
current waveform to follow a sinusoidal reference, the AC mains voltage.
6. vii
fig. 2.1 Uncorrected SMPS voltage & current waveform
The electricity supply industry is undergoing a profound transformation worldwide.
Market forces, scarcer natural resources, and an ever-increasing demand for electricity are
some of the drivers responsible for such unprecedented change. Against this background of
rapid evolution, the expansion programs of many utilities are being thwarted by a variety of
well-founded, environment, land-use, and regulatory pressures that prevent the licensing and
building of new transmission lines and electricity generating plants.
The ability of the transmission system to transmit power becomes impaired by one or
more of the following steady state and dynamic limitations:
(a) Angular stability,
(b) Voltage magnitude,
(c) Thermal limits,
(d) Transient stability, and
(e) Dynamic stability.
7. viii
These limits define the maximum electrical power to be transmitted without causing
damage to transmission lines and electrical equipment. In principle, limitations on power
transfer can always be relieved by the addition of new transmission lines and generation
facilities. Alternatively, flexible alternating current transmission system (FACTS) controllers
can enable the same objectives to be met with no major alterations to power system layout.
FACTS are alternating current transmission systems incorporating power electronic-based
and other static controllers to enhance controllability and increase power transfer capability.
The FACTS concept is based on the substantial incorporation of power electronic devices and
methods into the high-voltage side of the network, to make it electronically controllable.
2.1 OBJECTIVES OF FACTS CONTROLLERS
The main objectives of FACTS controllers are the following:
1. Regulation of power flows in prescribed transmission routes.
2. Secure loading of transmission lines nearer to their thermal limits.
3. Prevention of cascading outages by contributing to emergency control.
4. Damping of oscillations that can threaten security or limit the usable line capacity.
The implementation of the above objectives requires the development of high power
compensators and controllers. The technology needed for this is high power electronics with
real-time operating control. The realization of such an overall system optimization control
can be considered as an additional objective of FACTS controllers.
2.2 BASIC TYPES OF FACTS CONTROLLERS
In general, FACTS Controllers can be divided into four categories:
• Series Controllers
• Shunt Controllers
• Combined series-series Controllers
• Combined series-shunt Controllers
The general symbol for a FACTS Controller: a thyristor arrow inside a box.
8. ix
fig. 2.1 Basic types of FACTS Controllers
fig.2.2 Basic types of FACTS Controllers
(a) General symbol for FACTS Controller
(b) Series Controller
(c) Shunt Controller
(d) Unified series-series Controller
(e) coordinated series and shunt Controller
(f) Unified –shunt Controller
(g) Unified Controller for multiple lines
(h) Series Controller with storage
(i) Shunt Controller with storage
(j) Unified series-shunt Controller with storage.
9. x
2.2.1 SERIES CONTROLLERS:
The series Controller could be variable impedance, such as capacitor, reactor, etc., or
power electronics based variable source of main frequency, sub-synchronous and harmonic
frequencies (or a combination) to serve the desired need. In principle, all series Controllers
inject voltage in series with the line. Even variable impedance multiplied by the current flow
through it, represents an injected series voltage in the line. As long as the voltage is in phase
quadrature with the line current, the series Controller only supplies or consumes variable
reactive power. Any other phase relationship will involve handling of real power as well.
2.2.2 SHUNT CONTROLLERS:
As in the case of series Controllers, the shunt Controllers may be variable impedance,
variable source, or a combination of these. In principle, all shunt Controllers inject current
into the system at the point of connection. Even a variable shunt impedance connected to the
line voltage causes a variable current flow and hence represents injection of current into the
line. As long as the injected current is in phase quadrature with the line voltage, the shunt
Controller only supplies or consumes variable reactive power. Any other phase relationship
will involve handling of real power as well.
2.2.3 COMBINED SERIES-SERIES CONTROLLERS:
This could be a combination of separate series controllers, which are controlled in a
coordinated manner, in a multiline transmission system. Or it could be a unified Controller,
figure 2.3, in which series Controllers provide independent series reactive compensation for
each line but also transfer real power among the lines via the power link. The real power
transfer capability of the unified series-series Controller, referred to as Interline Power Flow
Controller, makes it possible to balance both the real and reactive power flow in the lines and
thereby maximize the utilization of the transmission system. Note that the term "unified" here
means that the de terminals of all Controller converters are all connected together for real
power transfer.
2.2.4 COMBINED SERIES-SHUNT CONTROLLERS:
This could be a combination of separate shunt and series Controllers, which are
controlled in a coordinated manner or a Unified Power Flow Controller with series and shunt
elements. In principle, combined shunt and series Controllers inject current into the system
10. xi
with the shunt part of the Controller and voltage in series in the line with the series part of the
Controller. However, when the shunt and series Controllers are unified, there can be a real
power exchange between the series and shunt Controllers via the power link.
2.3 BENEFITS OF FACTS CONTROLLERS
FACTS controllers enable the transmission owners to obtain, on a case-by-case basis,
one or more of the following benefits:
1. Cost: Due to high capital cost of transmission plant, cost considerations frequently
overweigh all other considerations. Compared to alternative methods of solving transmission
loading problems, FACTS technology is often the most economic alternative.
2. Convenience: All FACTS controllers can be retrofitted to existing ac transmission plant
with varying degrees of ease. Compared to high voltage direct current or six-phase
transmission schemes, solutions can be provided without wide scale system disruption and
within a reasonable timescale.
3. Control of power flow to follow a contract, meet the utilities own needs, ensure optimum
power flow, minimize the emergency conditions, or a combination thereof.
4. Contribute to optimal system operation by reducing power losses and improving voltage
profile.
5. Increase the loading capability of the lines to their thermal capabilities, including short
term and seasonal.
6. Increase the system security by raising the transient stability limit, limiting short-circuit
currents and overloads, managing cascading blackouts and damping electromechanical
oscillations of power systems and machines.
11. xii
CHAPTER 3
BASIC PRINCIPLE OF UPFC
The continuing rapid development of high-power semiconductor technology now
makes it possible to control electrical power systems by means of power electronic devices.
These devices constitute an emerging technology called FACTS (flexible alternating current
transmission systems). FACTS technology has a number of benefits, such as greater power
flow control, increased secure loading of existing transmission circuits, damping of power
system oscillations, less environmental impact and, potentially, less cost than most alternative
techniques of transmission system reinforcement. The UPFC is the most versatile of the
FACTS devices. It cannot only perform the functions of the static synchronous compensator
(STATCOM), thyristor switched capacitor (TSC) thyristor controlled reactor (TCR), and the
phase angle regulator but also provides additional flexibility by combining some of the
functions of the above controllers. Both the magnitude and the phase angle of the voltage can
be varied independently. Real and reactive power flow control can allow for power flow in
prescribed routes, loading of transmission lines closer to their thermal limits and can be
utilized for improving transient and small signal stability of the power system. The schematic
of the UPFC is shown in Fig.3.1
12. xiii
fig.3.1 Schematic diagram of UPFC
The UPFC consists of two branches. The series branch consists of a voltage source converter,
which injects a voltage in series through a transformer. The inverter at the input end of the
UPFC is connected in shunt to the AC power system and the inverter at the input end of the
UPFC is connected in series with the AC transmission circuit. Since the series branch of the
UPFC can inject a voltage with variable magnitude and phase angle it can exchange
real power with the transmission line. However the UPFC as a whole cannot supply or absorb
real power in steady state (except for the power drawn to compensate for the losses) unless it
has a power source at its DC terminals. The UPFC can control the transmission real power, at
its series-connected output end, while independently providing reactive power support to the
transmission line at its shunt-connected input end. Furthermore, the UPFC can independently
control real and reactive power flow along the transmission line at its output end, while
providing reactive power support to the transmission line at its input end. It has been shown
that it is possible to independently control real and reactive power flow at the UPFC input
circuit by regulating the DC-link capacitor voltage and varying both the phase angle and the
modulation index of the input inverter. The DC-link capacitor voltage (Vdc) is unregulated.
The main parameter of a power system i.e. line impedance (X), terminal voltage (V)
and Lt rotor angle (∂). The effectiveness of UPFC is analyzed by analyzing, damping of the
oscillation of rotor angle (∂) and change in angular speed (∂w) is analyzed in the three
machine of the 3-machine nine bus system. The control of an AC power system in real time is
involved because power flow is a function of the transmission line impedance, the magnitude
of the sending and receiving end voltages, and the phase angle between these voltages. Years
ago, electric power systems were relatively simple and were designed to be self-sufficient;
power exportation and importation were rare. Furthermore, it was generally understood that
13. xiv
AC transmission systems could not be controlled fast enough to handle dynamic system
conditions. The sustainability of a power system is the most important point.
3.1 OPERATING MODES OF UPFC
A Unified Power Flow Controller (or UPFC) is an electrical device for providing fast-
acting reactive power compensation on high-voltage electricity transmission networks. It uses
a pair of three-phase controllable bridges to produce current that is injected into a
transmission line using a series transformer. The controller can control active and reactive
power flows in a transmission line. The UPFC uses solid state devices, which provide
functional flexibility, generally not attainable by conventional thyristor controlled systems.
The UPFC is a combination of a static synchronous compensate or (STATCOM) and
a static synchronous series compensator (SSSC) coupled via a common DC voltage link. The
UPFC concept was described in 1995 by L. Gyugyi of Westinghouse. The UPFC allows a
secondary but important function such as stability control to suppress power system
oscillations improving the transient stability of power system.
The unified power flow controller (UPFC) is one of the most widely used FACTs
controllers and its main function is to control the voltage, phase angle and impedance of the
power system thereby modulating the line reactance and controlling the power flow in the
transmission line.
The basic components of the UPFC are two voltage source inverters (VSIs) connected
by a common dc storage capacitor which is connected to the power system through a
coupling transformers. One (VSIs) is connected in shunt to the transmission system through a
shunt transformer, while the other (VSIs) is connected in series to the transmission line
through a series transformer. Three phase system voltage of controllable magnitude and
phase angle (Vc) are inserted in series with the line to control active and reactive power flows
in the transmission line. So, this inverter will exchange active and reactive power with in the
line. The shunt inverter is operated in such a way as to demand this dc terminal power
(positive or negative) from the line keeping the voltage across the storage capacitor (Vdc)
constant. So, the net real power absorbed from the line by the UPFC is equal to the only
losses of the inverters and the transformers. The remaining capacity of the shunt inverter can
be used to exchange reactive power with the line so to provide a voltage regulation at the
connection point.
The two VSI‟s can work independently from each other by separating the dc side. So
in that case, the shunt inverter is operating as a (STATCOM) that generates or absorbs
14. xv
reactive power to regulate the voltage magnitude at the connection point. The series inverter
is operating as (SSSC) that generates or absorbs reactive power to regulate the current
flowing in the transmission line and hence regulate the power flows in the transmission line.
The UPFC has many possible operating modes.
fig.3.2 vector representation of UPFC
3.1.1 SHUNT INVERTER
The shunt inverter is operated in such a way as to draw a controlled current from the line.
One component of this current is automatically determined by the requirement to balance the
real power of the series inverter. The remaining current component is reactive and can be set
15. xvi
to any desired reference level (inductive or capacitive) within the capability of the inverter.
The reactive compensation control modes of the shunt inverter are very similar to those
commonly employed on conventional static VAR compensators.
(1) VAR control mode:-The reference input is a simple var request that is maintained by the
control system regardless of bus voltage variation.
(2) Automatic voltage control mode:-The shunt inverter reactive current is automatically
regulated to maintain the transmission line voltage at the point of connection to a reference
value with a defined slope characteristics the slope factor defines the per unit voltage error
per unit of inverter reactive current within the current range of the inverter. In Particular, the
shunt inverter is operating in such a way to inject a controllable current into the transmission
line. The figure 3.3 shows how the (UPFC) is connected to the transmission line.
fig.3.3 shows the UPFC installed in a transmission line
16. xvii
3.1.2 SERIES INVERTER
The series inverter controls the magnitude and angle of the voltage injected in series
with the line. This voltage injection is always intended to influence the flow of power on the
line, but the
actual value of the injected voltage can be determined in several different ways. These
include:
DIRECT VOLTAGE INJECTION MODE
The series inverter simply generates a voltage vector with magnitude and phase angle
requested by reference input. A special case of direct voltage injection is when the injected
voltage is kept in quadrature with the line current to provide purely reactive series
compensation. The series inverter injects the appropriate voltage so that the voltage V, is
phase shifted relative to the voltage VI by an angle specified by reference input.
LINE IMPEDANCE EMULATION MODE.
The series injected voltage is controlled in proportion to the line current so that the series
insertion transformer appears as an impedance when viewed from the line. The desired
impedance is specified by reference input and in general it may be a complex impedance with
resistive and reactive components of either polarity. Naturally care must be taken in this
mode to avoid values of negative resistance or capacitive reactance that would cause
resonance or instability.
AUTOMATIC POWER FLOW CONTROL MODE.
The UPFC has the unique capability of independently controlling both the real power
flow. P, on a transmission line and the reactive power, Q, at a specified point. This capability
can be appreciated by interpreting the series injected voltage, Vi",; as a controllable two
dimensional vector quantity. This injected voltage vector can be chosen appropriately to force
any desired current vector (within limits) to flow on the line, hence establishing a
corresponding power flow. In automatic power flow control mode, the series injected voltage
is determined automatically and continuously by a vector control system to ensure that the
desired P and Q are maintained despite system changes.
17. xviii
fig.3.4 Shows the Single line diagram of a 500kv/230kv transmission system using UPFC
3.2 DESCRIPTION OF SINGLE LINE DIAGRAM:
The power flow in a 500 kV /230 kV transmission systems is shown in single line in
fig 2. The system is connected in a loop configuration, consists of five buses (B1 to B5)
interconnected through three transmission lines (L1, L2, L3) and two 500 kV/230 kV
transformer banks Tr1 and Tr2. Two power plants located on the 230 kV system generate a
total of 1500 MW (illustrated in figure 2) which is transmitted to a 500 kV, 15000 MVA
equivalent and to a 200 MW load connected at bus B3. Each plant model includes a speed
regulator, an excitation system as well as a power system stabilizer (PSS). In normal
operation, most of the 1200 MW generating capacity power plant P1 is exported to the 500
18. xix
kV equivalents through two 400 MVA transformer connected between buses B4 and B5 .The
UPFC is connected at the right end of line L2 is used to control the active and reactive power
at the 500kv bus B3 the UPFC used here include two 100 MVA, IGBT based converters (one
series converter and one shunt converter) both the converter are interconnected through a DC
bus two voltage source inverter connected by a capacitor charged to a DC voltage realize the
UPFC the converter number one which is a shunt converter draws real power from the source
and exchange it (minus the losses) to the series converter the power balance between the
shunt and series converter is maintained to keep the voltage across the DC link capacitor
constant. The single line diagram is implemented on MATLAB Simulink.
The series converter is rated 100MVA with a maximum voltage injection of 0.1pu the
shunt converter is also rated 100MVA the shunt converter is operated in voltage control mode
and the series converter is operated in power flow control mode the series converter can
inject a maximum of 10% of nominal line to ground voltage.
fig.3.5 Unified Power Flow Controller
3.3 STATIC COMPENSATOR (STATCOM)
The emergence of FACTS devices and in particular GTO thyristor-based STATCOM
has enabled such technology to be proposed as serious competitive alternatives to
conventional SVC.A static synchronous compensator (STATCOM) is a regulating device
used on alternating current electricity transmission networks. It is based on a power
electronics voltage-source converter and can act as either a source or sink of reactive AC
power to an electricity network. If connected to a source of power it can also provide active
AC power. It is a member of the FACTS family of devices. Usually a STATCOM is installed
19. xx
to support electricity networks that have a poor power factor and often poor voltage
regulation. There are however, other uses, the most common use is for voltage stability.
fig.3.6 Static Compensator (STATCOM)
3.4 STATIC SYNCHRONOUS SERIES COMPENSATOR (SSSC)
SSSC consists of a static synchronous generator, operated without an external electric
energy source as a series compensator whose output voltage is in quadrature with, and
controllable independently of, the line current for the purpose of increasing or decreasing the
overall reactive voltage drop across the line and thereby controlling the transmitted electric
power. The SSSC may include transiently rated energy storage or energy absorbing devices
to enhance the dynamic behavior of the power system by additional temporary real power
compensation, to increase or decrease momentarily, the overall real (resistive) voltage drop
across the line.
20. xxi
fig.3.7 Schematic diagram of SSSC
.
3.5 Disadvantage
1. Large Line Losses (Copper Losses)
2. Large KVA rating and Size of Electrical equipments
3. Greater Conductor Size and Cost
4. Poor Voltage Regulation and Large Voltage Drop
5. Low Efficiency
6. Penalty from Electric Power Supply Company on Low Power factor
21. xxii
CHAPTER 4
APPLICATION
1. Use of UPFC for optimal power flow control.
2. Increase transient stability of inter- area power system.
3. Use for damping power system oscillation.
4. For improving microgrid voltage profile.
5. For enhancement of voltage profile and minimization of losses.
6. Use in HVDC transmission system.
22. xxiii
CHAPTER 5
CONCLUSION
UPFC is a FACT device used to control the active and reactive power flow. The
overall result over the power system is that it improved the power factor. So it brings the
present power system at better economy level. Power system stability is one of the key issues
in the today’s world. And many different techniques have been used to improve the stability.
The FACTS devices-Unified Power Flow Controller UPFC and its performance has been
studied under the transient condition to enhance power system stability in the usage as power
system stabilizer.
23. xxiv
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