Three-phase short circuit testing of high-voltage circuit breakersusing 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 SF/sub 6/ interrupting chambers, which 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 the interruption of short-circuit currents and, especially, the testing of short-circuit currents that have a nonpassage by zero on such a new chamber for applications to generator circuit breakers are shown and evaluated.     

高压断路器灭弧过程的数字分析

论述为了分析和研究高压断路器灭弧室内的气体流动以及减少试验次数,越来越多使用的计算性流体动力工具(CFD工具).这些工具通过集成十分复杂的模型,建立在传统物理流体动力方程式的基础上.SF6灭弧室的可变参数量如今根据具体应用的不同已经非常庞大,这些工具容许更好地进行评估、分析、并且理解开断过程,可以有助于对断路器灭弧室的形状和几何参数的优化.     

Circuit breakers go high voltage

TThe first Sulfur hexafluoride (sf6) gas industrial developments were in the medium voltage range. This equipment confirmed the advantages of a technique that uses sf6 at a low-pressure level concurrently with the auto-pneumatic blast system to interrupt the arc that was called later puffer. High-voltage sf6 circuit breakers with self-blast interrupters have found worldwide acceptance because their high current interrupting capability is obtained with a low operating energy that can be provided by low-cost, spring-operated mechanisms. The low-operating energy required reduces the stress and wear of the mechanical components and significantly improves the overall reliability of the circuit breaker. This switching principle was first introduced in the highvoltage area about 20 years ago, starting with the voltage level of 72.5 kV. Today this technique is available up to 800 kV. Furthermore it is used for generator circuit breaker applications with short circuit currents of 63 kA and above. Service experience shows that when the sf6circuit breakers of the self-blast technology were first designed, the expectations of the designers had been fulfilled completely with respect to reliability and day-to-day operation.