There are three main types of protective relays: electromechanical, static, and digital. Electromechanical relays include the plunger type, clapper type, and electromagnetic induction disc type. Protective relays are used for over current protection and have definite tripping characteristics, with potential drawbacks that digital and static relays aim to address.
This document discusses electrical protection methods for power systems. It covers over current protection, differential protection, and impedance overvoltage protection which are techniques used to detect faults and disconnect affected system components.
1) Cathodic protection controls corrosion by making the entire metal surface a cathode through the use of an external current source. This stops the metal from corroding by acting as the anode in an electrochemical cell.
2) There are two main types of cathodic protection systems - sacrificial anode systems which use more electrically active metals as anodes that corrode instead of the structure, and impressed current systems which use an external current source such as transformers.
3) Proper installation and material selection is important for cathodic protection systems to function effectively. Factors like soil conditions, coating quality, and reference electrodes must be considered to ensure adequate protection and prevent overprotection of the metal surface.
The document outlines a plan for training technicians on safety procedures and maintenance processes. It details topics that will be covered including identifying Siemens equipment, safety for personnel and equipment, and the different types of maintenance like preventive and corrective. The training will teach technicians to wear personal protective equipment, prepare necessary tools, process errors from previous preventive maintenance, and identify checklists for each maintenance task. Safety measures, equipment identification, and proper maintenance procedures will be the focus of the training.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It describes:
- Circuit breakers consist of contacts, operating mechanisms, trip and close coils, and auxiliary switches. They are rated by voltage and breaking capacity.
- Current transformers reduce high currents to safely measurable levels for meters and relays. They are rated by voltage, current ratios, and accuracy class.
- Voltage transformers reduce high voltages to safely measurable levels. They are rated by voltage, turns ratio, and accuracy class.
This document summarizes cooling systems and components for power transformers. It discusses two main cooling types: air and oil. Oil-filled transformers use natural circulation or forced circulation with pumps and fans. Transformer components described include the core, windings, tank, radiators, conservator tank, breather unit, bushings, and tap changer. Harmonic effects and different connection types such as star-star, delta-star, and delta-delta are also covered.
This document summarizes information about power transformers, including their objectives, advantages, classification, construction, manufacturing, cooling systems, components, and connections. It discusses transformer types such as step-up, step-down, single and three phase transformers. It also covers transformer components like the core, windings, insulation, and cooling systems using oil circulation and fans.
Motor protection is divided into unfavorable operating conditions, faulty conditions, and system disturbances. Unfavorable operating conditions include mechanical overloads, under voltage, reverse rotation, harmonic effects, and voltage unbalance, which can lead to high temperatures. Faulty conditions involve short circuits between phases, earth faults, stalled rotors, prolonged starting times, and increased start/stop cycles. Small and medium low-tension motors are protected against overloads.
There are three main types of protective relays: electromechanical, static, and digital. Electromechanical relays include the plunger type, clapper type, and electromagnetic induction disc type. Protective relays are used for over current protection and have definite tripping characteristics, with potential drawbacks that digital and static relays aim to address.
This document discusses electrical protection methods for power systems. It covers over current protection, differential protection, and impedance overvoltage protection which are techniques used to detect faults and disconnect affected system components.
1) Cathodic protection controls corrosion by making the entire metal surface a cathode through the use of an external current source. This stops the metal from corroding by acting as the anode in an electrochemical cell.
2) There are two main types of cathodic protection systems - sacrificial anode systems which use more electrically active metals as anodes that corrode instead of the structure, and impressed current systems which use an external current source such as transformers.
3) Proper installation and material selection is important for cathodic protection systems to function effectively. Factors like soil conditions, coating quality, and reference electrodes must be considered to ensure adequate protection and prevent overprotection of the metal surface.
The document outlines a plan for training technicians on safety procedures and maintenance processes. It details topics that will be covered including identifying Siemens equipment, safety for personnel and equipment, and the different types of maintenance like preventive and corrective. The training will teach technicians to wear personal protective equipment, prepare necessary tools, process errors from previous preventive maintenance, and identify checklists for each maintenance task. Safety measures, equipment identification, and proper maintenance procedures will be the focus of the training.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It describes:
- Circuit breakers consist of contacts, operating mechanisms, trip and close coils, and auxiliary switches. They are rated by voltage and breaking capacity.
- Current transformers reduce high currents to safely measurable levels for meters and relays. They are rated by voltage, current ratios, and accuracy class.
- Voltage transformers reduce high voltages to safely measurable levels. They are rated by voltage, turns ratio, and accuracy class.
This document summarizes cooling systems and components for power transformers. It discusses two main cooling types: air and oil. Oil-filled transformers use natural circulation or forced circulation with pumps and fans. Transformer components described include the core, windings, tank, radiators, conservator tank, breather unit, bushings, and tap changer. Harmonic effects and different connection types such as star-star, delta-star, and delta-delta are also covered.
This document summarizes information about power transformers, including their objectives, advantages, classification, construction, manufacturing, cooling systems, components, and connections. It discusses transformer types such as step-up, step-down, single and three phase transformers. It also covers transformer components like the core, windings, insulation, and cooling systems using oil circulation and fans.
Motor protection is divided into unfavorable operating conditions, faulty conditions, and system disturbances. Unfavorable operating conditions include mechanical overloads, under voltage, reverse rotation, harmonic effects, and voltage unbalance, which can lead to high temperatures. Faulty conditions involve short circuits between phases, earth faults, stalled rotors, prolonged starting times, and increased start/stop cycles. Small and medium low-tension motors are protected against overloads.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It provides specifications for each component and describes their functions. Troubleshooting tips are also included, outlining common issues with circuit breakers not closing or opening and potential remedies.
Single-line diagrams provide an overview of electrical systems using simplified lines to represent connections between components rather than actual wiring. Circuit diagrams visually display electrical circuits using images or standard symbols. Schematic diagrams illustrate the functional plan of a circuit without depicting physical wire placement, using abstract symbols. Wiring diagrams visually map the physical layout and connections of an electrical system or circuit using wires and showing where fixtures connect.
The document discusses current transformers (CTs), including their construction, testing, and common problems. CTs are used to step down high currents to safely measurable levels for protection devices and meters. They are tested through turns ratio tests, saturation tests, polarity tests, and winding resistance tests to evaluate accuracy. Common CT issues found on site include shorted, open, miswired, unwired, backwards installed, incorrect, and defective CTs. Potential transformers are also mentioned.
This document discusses power cables and their properties. It covers several topics:
- The electrical properties of cables including conductor resistance, capacitance, inductance, and electrical field.
- Insulation materials used in cables like PVC, XLPE, and EPR and their advantages and disadvantages.
- Factors that influence cable breakdown voltage and how to prevent cable faults.
- The effects of sheath on cable losses and how to reduce them.
- Tests conducted on cables and cable fault localization.
Motor protection is divided into unfavorable operating conditions, faulty conditions, and system disturbances. Unfavorable operating conditions include mechanical overloads, under voltage, reverse rotation, harmonic effects, and voltage unbalance, which can lead to high temperatures. Faulty conditions involve short circuits between phases, earth faults, stalled rotors, prolonged starting times, and increased start/stop cycles. Small and medium low-tension motors are protected against overloads.
The document discusses different methods for starting electric motors, including direct-on-line start, star-delta start, and using rotor resistance or a soft starter device. Star-delta start has disadvantages like lower starting torque and requiring six motor terminals. Rotor resistance starting provides higher torque but cannot be used with squirrel cage motors. Soft starter devices provide gradual voltage increases, reducing mechanical shocks and current spikes while maintaining the network voltage, at the cost of higher price.
The document discusses various protection methods for generators, including:
1. 90% stator earth fault protection which detects faults in the stator windings using voltage or current measurement.
2. 100% stator earth fault protection using 20Hz voltage injection to determine fault resistance.
3. Rotor earth fault protection using 1-3Hz square wave voltage injection and measurement of the resulting current.
4. Out-of-step and negative sequence protections which detect loss of synchronism and unbalanced loads respectively.
This document contains exercises for machine protection using the Siemens SIPROTEC 7VE6 relay. It includes single line diagrams of generator and transformer connections, device configuration steps, power system data, exercises on synchronizing a generator, and instructions for connecting the 7VE6 relay to test equipment for further exercises. The exercises guide users through setup and testing of generator and transformer protection functions.
The document discusses numerical paralleling devices 7VE61 and 7VE63 from Siemens. The devices synchronize generators and close circuit breakers to parallel power systems. They provide high reliability through dual channel design with two independent measuring principles and a two out of two decision for issuing close commands. Additional supervision functions monitor inputs, internal logic, and close relays to detect faults and ensure safe and reliable paralleling of power systems.
This document discusses methods for 100% stator earth fault protection on generators. It begins by explaining the limitations of traditional displacement voltage and earth current protection during faults close to the star point. It then describes using the third harmonic component of voltage or injecting a 20 Hz voltage as alternatives. The document provides details on measuring third harmonics, limitations of that method, and the components and design of a 20 Hz injection system. It also discusses compensating for errors and calibration of the protection. In summary, the document focuses on overcoming protection blind spots during star point faults by evaluating harmonic components or injecting a frequency, along with practical implementation considerations.
This document discusses methods for stator earth fault protection in generators. It presents:
1) Different methods of neutral point grounding and their advantages/disadvantages.
2) How earth fault voltages and currents behave depending on the fault location for different generator connections.
3) Techniques for measuring earth fault currents including use of a toroidal current transformer and Holmgreen connection.
This document discusses underexcitation protection, also called loss of field protection, for synchronous generators. It provides reasons for underexcitation including failures of the excitation device. Consequences of excitation failures can include rotor acceleration, overheating, and grid oscillations. The admittance protection criterion is proposed, which considers how the generator stability limit moves when voltage decreases. It involves transforming the generator capability diagram into an admittance diagram to set straight-line characteristics based on the stability limits.
This document discusses rotor earth fault protection for generators. It begins by explaining the problem of earth faults causing magnetic imbalances and high currents. It then describes the requirements for rotor earth fault protection, including detecting earth faults early. The document provides details on different methods for rotor earth fault protection using numerical relays, including injecting AC voltages at 50/60 Hz or square waves at 1-3 Hz to measure earth currents and calculate fault resistances. Diagrams and formulas are given to illustrate the operating principles and calculations. Settings, logic diagrams, and connections are discussed for implementation of numerical rotor earth fault protection.
1) The document discusses differential protection for transformers, generators, and motors. It describes the measuring principle of differential protection which compares currents entering and leaving a device.
2) Numerical relays can implement differential protection functions and compensate for issues like non-matching current transformers, vector groups, and dynamic currents.
3) The Siemens 7UM62 and 7UT6xx relay families provide differential protection capabilities for devices with two or three winding configurations.
This document provides information about Siemens' SIPROTEC 4 numerical protection devices. It discusses the SIPROTEC 4 family of devices, the features and capabilities of the 7UM61 protection unit, and examples of communication solutions and applications for generator, motor, and transformer protection. The training presentation explores the advantages of numerical protection and flexible communication interfaces in the SIPROTEC 4 system.
This document provides an overview of machine protection for generators and motors. It discusses the types of faults that can occur internally and externally and the corresponding protection functions used. Some key protection functions discussed include differential protection, overcurrent protection, impedance protection, stator and rotor earth fault protection, unbalanced load protection, reverse power protection, over/under voltage protection, over/under frequency protection, and others. It also discusses considerations for the selection of protection functions based on the rated power of the generator. Finally, it covers redundancy concepts for protection including full redundancy and partial redundancy.
This document provides information and configuration settings for machine protection exercises using a Siemens SIPROTEC 7UM62 relay. It includes the single line diagram of the power system with a 50 MVA generator. It lists the protection elements required for the exercises, which are overcurrent, reverse power, decoupling, differential protection, stator earth fault, unbalanced load, and under excitation protection. Device and protection function settings are provided on primary and secondary bases. Connection details are shown for voltage, current, trip signals and binary inputs between the 7UM62 relay and CMC test set. Generator data including nameplate values and capability curves are also included for reference in setting calculations.
The document summarizes key components and operating principles of switchgear, including circuit breakers, current transformers, and voltage transformers. It provides specifications for each component and describes their functions. Troubleshooting tips are also included, outlining common issues with circuit breakers not closing or opening and potential remedies.
Single-line diagrams provide an overview of electrical systems using simplified lines to represent connections between components rather than actual wiring. Circuit diagrams visually display electrical circuits using images or standard symbols. Schematic diagrams illustrate the functional plan of a circuit without depicting physical wire placement, using abstract symbols. Wiring diagrams visually map the physical layout and connections of an electrical system or circuit using wires and showing where fixtures connect.
The document discusses current transformers (CTs), including their construction, testing, and common problems. CTs are used to step down high currents to safely measurable levels for protection devices and meters. They are tested through turns ratio tests, saturation tests, polarity tests, and winding resistance tests to evaluate accuracy. Common CT issues found on site include shorted, open, miswired, unwired, backwards installed, incorrect, and defective CTs. Potential transformers are also mentioned.
This document discusses power cables and their properties. It covers several topics:
- The electrical properties of cables including conductor resistance, capacitance, inductance, and electrical field.
- Insulation materials used in cables like PVC, XLPE, and EPR and their advantages and disadvantages.
- Factors that influence cable breakdown voltage and how to prevent cable faults.
- The effects of sheath on cable losses and how to reduce them.
- Tests conducted on cables and cable fault localization.
Motor protection is divided into unfavorable operating conditions, faulty conditions, and system disturbances. Unfavorable operating conditions include mechanical overloads, under voltage, reverse rotation, harmonic effects, and voltage unbalance, which can lead to high temperatures. Faulty conditions involve short circuits between phases, earth faults, stalled rotors, prolonged starting times, and increased start/stop cycles. Small and medium low-tension motors are protected against overloads.
The document discusses different methods for starting electric motors, including direct-on-line start, star-delta start, and using rotor resistance or a soft starter device. Star-delta start has disadvantages like lower starting torque and requiring six motor terminals. Rotor resistance starting provides higher torque but cannot be used with squirrel cage motors. Soft starter devices provide gradual voltage increases, reducing mechanical shocks and current spikes while maintaining the network voltage, at the cost of higher price.
The document discusses various protection methods for generators, including:
1. 90% stator earth fault protection which detects faults in the stator windings using voltage or current measurement.
2. 100% stator earth fault protection using 20Hz voltage injection to determine fault resistance.
3. Rotor earth fault protection using 1-3Hz square wave voltage injection and measurement of the resulting current.
4. Out-of-step and negative sequence protections which detect loss of synchronism and unbalanced loads respectively.
This document contains exercises for machine protection using the Siemens SIPROTEC 7VE6 relay. It includes single line diagrams of generator and transformer connections, device configuration steps, power system data, exercises on synchronizing a generator, and instructions for connecting the 7VE6 relay to test equipment for further exercises. The exercises guide users through setup and testing of generator and transformer protection functions.
The document discusses numerical paralleling devices 7VE61 and 7VE63 from Siemens. The devices synchronize generators and close circuit breakers to parallel power systems. They provide high reliability through dual channel design with two independent measuring principles and a two out of two decision for issuing close commands. Additional supervision functions monitor inputs, internal logic, and close relays to detect faults and ensure safe and reliable paralleling of power systems.
This document discusses methods for 100% stator earth fault protection on generators. It begins by explaining the limitations of traditional displacement voltage and earth current protection during faults close to the star point. It then describes using the third harmonic component of voltage or injecting a 20 Hz voltage as alternatives. The document provides details on measuring third harmonics, limitations of that method, and the components and design of a 20 Hz injection system. It also discusses compensating for errors and calibration of the protection. In summary, the document focuses on overcoming protection blind spots during star point faults by evaluating harmonic components or injecting a frequency, along with practical implementation considerations.
This document discusses methods for stator earth fault protection in generators. It presents:
1) Different methods of neutral point grounding and their advantages/disadvantages.
2) How earth fault voltages and currents behave depending on the fault location for different generator connections.
3) Techniques for measuring earth fault currents including use of a toroidal current transformer and Holmgreen connection.
This document discusses underexcitation protection, also called loss of field protection, for synchronous generators. It provides reasons for underexcitation including failures of the excitation device. Consequences of excitation failures can include rotor acceleration, overheating, and grid oscillations. The admittance protection criterion is proposed, which considers how the generator stability limit moves when voltage decreases. It involves transforming the generator capability diagram into an admittance diagram to set straight-line characteristics based on the stability limits.
This document discusses rotor earth fault protection for generators. It begins by explaining the problem of earth faults causing magnetic imbalances and high currents. It then describes the requirements for rotor earth fault protection, including detecting earth faults early. The document provides details on different methods for rotor earth fault protection using numerical relays, including injecting AC voltages at 50/60 Hz or square waves at 1-3 Hz to measure earth currents and calculate fault resistances. Diagrams and formulas are given to illustrate the operating principles and calculations. Settings, logic diagrams, and connections are discussed for implementation of numerical rotor earth fault protection.
1) The document discusses differential protection for transformers, generators, and motors. It describes the measuring principle of differential protection which compares currents entering and leaving a device.
2) Numerical relays can implement differential protection functions and compensate for issues like non-matching current transformers, vector groups, and dynamic currents.
3) The Siemens 7UM62 and 7UT6xx relay families provide differential protection capabilities for devices with two or three winding configurations.
This document provides information about Siemens' SIPROTEC 4 numerical protection devices. It discusses the SIPROTEC 4 family of devices, the features and capabilities of the 7UM61 protection unit, and examples of communication solutions and applications for generator, motor, and transformer protection. The training presentation explores the advantages of numerical protection and flexible communication interfaces in the SIPROTEC 4 system.
This document provides an overview of machine protection for generators and motors. It discusses the types of faults that can occur internally and externally and the corresponding protection functions used. Some key protection functions discussed include differential protection, overcurrent protection, impedance protection, stator and rotor earth fault protection, unbalanced load protection, reverse power protection, over/under voltage protection, over/under frequency protection, and others. It also discusses considerations for the selection of protection functions based on the rated power of the generator. Finally, it covers redundancy concepts for protection including full redundancy and partial redundancy.
This document provides information and configuration settings for machine protection exercises using a Siemens SIPROTEC 7UM62 relay. It includes the single line diagram of the power system with a 50 MVA generator. It lists the protection elements required for the exercises, which are overcurrent, reverse power, decoupling, differential protection, stator earth fault, unbalanced load, and under excitation protection. Device and protection function settings are provided on primary and secondary bases. Connection details are shown for voltage, current, trip signals and binary inputs between the 7UM62 relay and CMC test set. Generator data including nameplate values and capability curves are also included for reference in setting calculations.
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