Upload
others
View
5
Download
0
Embed Size (px)
Citation preview
Summary of Revision, IEEE C37.119-2016, Guide for
Breaker Failure Protection of Power Circuit Breakers
Kevin Donahoe – GE Grid Solutions
2018 Texas A&M Protective Relaying Conference
• Introduction
• Breaker Failure Minimal Current Scheme
• Current Differential Breaker Failure Protection
• Column Ground Protection
• Breaker Failure Protection for Generator Applications
• Redundant Control Circuits
• Conclusions
• Questions
Agenda
Introduction • Replaced C37.119-2005 • PSRC Working Group followed up with the paper “Summary
of Revision, IEEE C37.119-2016, Guide for Breaker Failure Protection of Power Circuit Breakers
• Definition of breaker failure protection (BFP) • 2005: This protection is specifically relied upon to take
appropriate action to clear a fault when the breaker that is normally expected to clear the fault fails to do so for any reason.
• 2016: A form of protection that is designed to detect the failure of a circuit breaker to operate or to interrupt a fault. Upon detection of a breaker failure during a fault condition the scheme is designed to take appropriate action to clear the fault. Upon detection of a breaker failure during a non-fault condition, the scheme may take other appropriate action.
Introduction
• Covered in C37.102, IEEE Guide for AC Generator Protection • BFP can fall in overlap between generation and transmission • Added clause increase familiarity with the unique
requirements for generator BFP • IEEE-Standards Association asked to expand the scope of
the C37-119 • Now includes performance failures of breakers other than
fault clearing failures • Failure to close during synchronizing is now covered
BF Minimal Current Scheme
• Breaker failure applications associated with high-impedance power system apparatus, such as generators, transformers, static var compensators (SVC), and harmonic filters, may have such low currents associated with internal faults that current detectors are not reliable.
• BF logic can also be achieved using breaker auxiliary switches
BF Minimal Current Scheme
Considerations
BF Minimal Current Scheme
BF Minimal Current Scheme
BF Minimal Current Scheme
• False BFI – one cause, accidental battery ground • Measures to reduce possibility of false BFI
• BFI input that responds only above half of the maximum battery voltage
• Binary inputs are compliant with IEC 60255-26, Measuring relays and protection equipment – Electromagnetic compatibility requirements with specific reference to Clause 7.2.7, Power frequency immunity on DC binary inputs
• Minimize cable run length and capacitance • Data communication-based means for conveying the BFI
between buildings
Current Differential BFP
• Accurate fault diagnosis • Extra installation and maintenance cost • Logical condition of adjacent operation of protection zones
Column Ground Protection
• CT column changes BFP
• No overlap • Most likely:
column to ground flashover
• CTs around the base of each column
• Direct trip of 86 • IEEE Std.
C37.234: Buses
BFP for Generator Applications
• Mechanical Indication of Breaker Status • CT Locations • Open Generator Breaker Flashover Protection • Breaker Arrangement: High-Side Breakers • Breaker Arrangement: Low-Side Breaker • Generator Breaker Failure to Close Protection
Mechanical Indication of Breaker Status
• Consider, in a motoring event, failure to separate from the power system can damage the prime mover
• A steam turbine has a typical motoring power range .5-3% • CTs sized for 5A at generator rating – current in milliamps • CTs on dual breakers, CTR may be based on bus rating • Current measurement is not reliable for all conditions
requiring BFP
CT Locations
• Even after the breakers open, the generator will feed a in-zone fault until stored energy in the field dissapates
• Never use generator neutral CTs • For low-side breaker location, not appropriate to use
generator terminals • CTs that measure the current flowing directly into the
breaker
Open Generator Breaker Flashover Protection
• Flashover most likely to occur just prior to synchronizing or just after the generator separates
Open Generator Breaker Flashover Protection
Breaker Arrangement: High-Side Breakers
Breaker Arrangement: High-Side Breakers
Breaker Arrangement: High-Side Breakers
Breaker Arrangement: Low-Side Breaker
• For Faults • Trip the generator CB G • Open the generator field breaker • Isolate the energy source that drives the prime mover
Generator BF to Close Protection
• Synchronizing systems minimize: • Speed difference or slip rate • Voltage difference • Angle difference
• Main contacts make at the instant when the angle difference is as near to zero as possible
• If breaker mechanism is slow then the generator rotor angle will pass zero and start increasing
• BFP could isolate the synchronizing breaker so that the generator closes into a dead bus
Generator BF to Close Protection
BFP on Redundant Control Circuits
Conclusions
• “Summary of Revision, IEEE C37.119-2016, Guide for Breaker Failure Protection of Power Circuit Breakers” is available at http://www.pes-psrc.org/kb/published/reports/Paper_SummaryofRevC37-119.pdf
• Go to pes-psrc.org • Go to Knowledge Base • Go to Reports • D subcommittee or search for 119
Thank You
Questions?