考虑开断顺序的断路器支路短路电流计算

Calculation of Short-Circuit Current of Circuit Breaker Branch Considering Breaking Sequences

针对目前断路器开断能力校核实践中只考虑短路点总电流而不考虑断路器实际可能通过的最大短路电流的问题,分析了同一支路中两侧断路器的动作工况对断路器通过的短路电流的影响,提出了计及断路器动作顺序的断路器支路可能出现的最大短路电流的计算方法。以某实际电网为例,定量计算、比较了流经断路器支路的最大短路电流和短路点总电流,指出目前以短路点总电流代替断路器可能流过的最大短路电流来校核断路器开断能力,因对断路器所需具备的断流能力要求过高而失当。

In view of the problem that only considers the total current of the short circuit point instead of the probable maximum short circuit current in breaking capacity checking practice of current circuit breaker,the impact of operation condition of the bilateral circuit breakers in the same branch on the short-circuit current was analyzed.And then the calculation method of the probable maximum short-circuit current is proposed considering the breaking sequences of circuit breaker.Taking an actual power grid as an example,the maximum short-circuit current in the branch of the circuit breaker and the total current of the short-circuit point were calculated.The case study shows that the breaking capacity of the circuit breaker should not be checked by the total current of the short circuit because it needs higher breaking capacity of circuit breaker.