Apr 2013
Electricity Transmission
Uneven Dynamic Voltages
Apr 2013
National Grid Electricity System Operator
National Grid TO Innovation Team
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Innovation Funding Incentive
Gas Distribution Networks
A number of in-service failures of circuit-breakers switching shunt reactors have occurred both in the UK and elsewhere. A theoretical explanation for the cause of failure has been proposed in collaboration with CIGRE Working Group A3.18 ‘Operating environment of circuit-breaker voltage grading capacitors’. Due to considerable practical difficulties in performing suitable measurements, it has not been possible to prove the theory experimentally. British Columbia Transmission Corporation (BCTC) has invited National Grid to participate in the proposed research project which aims to address the above shortcoming by performing tests in BCTC’s high power laboratory.
This project will demonstrate the uneven dynamic voltage distribution between circuitbreakers interrupters that is believed to be the cause of a number of in-service failures of devices switching shunt reactors. Successful demonstration of the phenomenon will allow design and type test requirements for circuit-breakers and their voltage grading capacitors to be specified, so that in service failures may be eliminated by design.