Abstract:
With the continuous development of the power grids, there has gradually been prominent of the problem of short-circuit current's exceeding of the standard. The short-circuit current limitation based on the dynamic adjustment of the system topology can avoid the equipment shutdown caused by the conventional limitation measures and thus decrease the impact on the normal operation of the system. This paper analyzes the influence of operating sequence of the circuit breakers on the short-circuit current. The calculation method of the short circuit current considering the topology adjustment process is proposed. The breaking current of the circuit breakers in typical substations is analyzed. The limiting effects and influencing factors of different topology adjustment schemes are analyzed. The action strategy of system topology adjustment and its influence on the current limiting speed are analyzed. For a 500kV system, the fast circuit breaker can be mainly arranged on the line. For a 220kV system, the fast circuit breaker can be mainly set at the bus line in section. The control strategy of topology adjustment can be implemented by the fast detection of faults with the branch current measuring or by the linkage operation with the relay protection.