Protection primer - Power System Protection Fundamentals...

Info iconThis preview shows pages 1–18. Sign up to view the full content.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Power System Protection Fundamentals What should we teach students about power system protection?
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Agenda Why protection is needed Principles and elements of the protection system Basic protection schemes Digital relay advantages and enhancements
Background image of page 2
Copyright © SEL 2008 Disturbances: Light or Severe The power system must maintain acceptable operation 24 hours a day Voltage and frequency must stay within certain limits Small disturbances The control system can handle these Example: variation in transformer or generator load Severe disturbances require a protection system They can jeopardize the entire power system They cannot be overcome by a control system
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Power System Protection Operation during severe disturbances: System element protection System protection Automatic reclosing Automatic transfer to alternate power supplies Automatic synchronization
Background image of page 4
Copyright © SEL 2008 Electric Power System Exposure to External Agents
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Damage to Main Equipment
Background image of page 6
Copyright © SEL 2008 Protection System A series of devices whose main purpose is to protect persons and primary electric power equipment from the effects of faults The “Sentinels”
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Blackouts Loss of service in a large area or population region Hazard to human life May result in enormous economic losses Overreaction of the protection system Bad design of the protection system Characteristics Main Causes
Background image of page 8
Copyright © SEL 2008 Short Circuits Produce High Currents Fault Substation a b c I Wire Three-Phase Line Thousands of Amps
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Electrical Equipment Thermal Damage I t I n I m d Damage Curve Short-Circuit Current Damage Time Rated Value
Background image of page 10
Copyright © SEL 2008 Mechanical Damage During Short Circuits Very destructive in busbars, isolators, supports, transformers, and machines Damage is instantaneous i 1 i 2 f 1 f 2 Rigid Conductors f 1 ( t ) = k i 1 ( t ) i 2 ( t ) Mechanical Forces
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 The Fuse Fuse Transformer
Background image of page 12
Copyright © SEL 2008 Protection System Elements Protective relays Circuit breakers Current and voltage transducers Communications channels DC supply system Control cables
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Three-Phase Diagram of the Protection Team CTs VTs Relay CB Control Protected Equipment
Background image of page 14
Copyright © SEL 2008 DC Tripping Circuit SI 52 TC DC Station Battery SI Relay Contact Relay Circuit Breaker 52a + Red Lamp
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Copyright © SEL 2008 Circuit Breakers
Background image of page 16
Copyright © SEL 2008 Current Transformers Very High Voltage CT Medium-Voltage CT
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 18
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 61

Protection primer - Power System Protection Fundamentals...

This preview shows document pages 1 - 18. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online