Denis Dufournet

Transient Recovery Voltages Requirements for System Source Fault Interrupting by Small Generator Circuit Breakers

Recent years have seen an increasing development of small generations of electric power. These generators of relatively low power, equal to or less than 100 MVA, are protected in an economic way by generator circuit breakers that are located between the generator and the step-up transformer. In 1997 the IEEE Switchgear Committee has issued a new edition of its standard C37-013 for generator circuit breakers, which covers mainly the applications with power transformers rated 100 MVA and above [1]. A revision of this standard is currently prepared by the IEEE Switchgear Committee in order to broaden its scope to all generator circuit breakers. The purpose of this paper is to contribute to the definition of TRV requirements for system-source faults in the case of small generator circuit breakers connected to the step-up transformer by cables.

Three-phase short circuit testing of high-voltage circuit breakers using synthetic circuits

High-voltage circuit-breakers have reached such high short-circuit breaking capabilities that they must be tested in synthetic circuits with separate current and voltage sources. As the main performance to be verified by type tests is the interruption of three-phase faults, it is desirable whenever possible to perform three-phase tests. Three-phase synthetic testing is rather new and not covered by ANSI/IEEE and IEC standards. The purpose of this paper is to present a procedure for three-phase synthetic testing which can properly test the circuit-breaker at a reasonable cost, i.e., a number of tests using a limited number of circuit-breaker specimens for the entire series of type tests.

Design and implementation of an SF/sub 6/ interrupting chamber applied to low range generator circuit breakers suitable for interruption of current having a non-zero passage

New types of SF6 intermupting chambers that implement innovative interrupting principles have been developed during the past years based on the objectives of reducing the operating energy of the circuit breakers and consequently increasing their reliability. This paper describes the rear-exhaust type self-blast double-volume thermal chamber, which was designed with the help of new chamber development software programs, of the physical imaging model of the arc. Simulations and confirmation by laboratories tests interruption of short circuit currents and especially tests short circuit currents having a nonpassage by zero on such new chamber for applications to generator circuit breakers are shown and evaluated.

Revision of IEEE C37.011 Guide for the Application of Transient Recovery Voltages for AC High-Voltage Circuit Breakers

A revision of IEEE C37.011 was done from 2008 to 2011 to improve the content of the 2005 edition on TRV interpolation for terminal fault, line fault, transformer limited fault and reactor limited fault. Another aim was to introduce class S1 and S2 circuit breakers for rated maximum voltages of less than 100 kV.

Investigations on Requirements for UHV/EHV AC Switchgear by CIGRE Study Committee A3

On request of IEC Technical Subcommittee 17A, CIGRE Study Committee A3 “High Voltage Equipment” investigated the requirements for ultra-high voltage ac switchgear, especially for parameters which cannot be extrapolated linearly from the corresponding equipment characteristics with lower-rated voltage, namely 800 kV. For circuit breakers, such aspects are the first pole-to-clear factor, the amplitude factor, the time to peak to define the transient recovery voltage envelope, the surge impedance of overhead lines, the damping and refraction of traveling waves, long-line faults, transformer-limited faults, initial transient recovery voltage, and the influence of shunt and series compensation. Disconnectors utilized for interrupting the bus transfer currents, bus charging currents and very fast transients, ground switches used for interrupting induced line currents, and high-speed ground or earthing switches have been studied as well. Based on these system and substation studies and simulations, recommendations have been provided to IEC SC 17A.