GENERATOR CIRCUIT BREAKERS : SF6 BREAKING CHAMBER – INTERRUPTION OF CURRENT WITH NON-ZERO PASSAGE - INFLUENCE OF CABLE CONNECTION ON TRV OF SYSTEM FED FAULTS

摘要

The last ten years have seen the development ofrnthe self-blast technique of interruption for SF6 HVrncircuit breakers. This technique has proved to bernvery efficient and has been widely applied for highrnvoltage circuit breakers up to 800 kV. The paperrnshows the application of the same technique tornthe development of SF6 generator circuit breakersrnwith spring-operated mechanisms.rnA particular characteristic of generator circuitrnbreakers is their mandatory capability to interruptrnshort-circuit currents with delayed current zeros.rnThis requirement of ANSI/IEEE Standard C37-013rnis explained in section 3 of this paper withrnexamples of breaking tests and simulations ofrncurrent interruption.rnIn 1997 the IEEE Switchgear Committee hasrnissued a new edition of its standard C37-013 forrngenerator circuit breakers, which covers mainly thernapplications with power transformers ratedrn100MVA and above [1]. A revision of this standardrnis done by the IEEE Switchgear Committee inrnorder to extend its scope to applications of lessrnthan 100MVA rated power. This paper presentsrncalculations that have been made to calculaternTRVs for system fed faults in the case of smallrngenerator circuit breakers connected to the step-uprntransformer by cables.