基于附加电感零序电压型小电流接地系统故障选线策略OA

Because of the small magnitude of zero sequence current,success rate of the fault line selection for a neutral un-effectual grounded system,especially for arc suppression coil grounding system,cannot be guaranteed.Furthermore,fault line selection based on applied signals are vulnerable to transition re-sistance.To solve the abovementioned problems,a fault line selection strategy for neutral un-effectual grounded system based on zero-sequence voltage of additional inductor is proposed.By putting in the additional inductor of each line in turn after a single-phase to ground fault occurs on the line,the fault line is determined according to the change of zero-sequence voltage at the busbar,using a cyclic deter-mination method,and fault line detection is realized.The theoretical derivation and the simulation based on PSCAD/EMTDC show that the proposed line selection strategy only needs to collect the zero-se-quence voltage,which requires low measurement accuracy and can accurately and reliably determine the fault line under different grounding modes of the system,and is less affected by the transition resistance.