T接暂态电流对有源配电网差动保护的影响与解决方法OA

To address protection issues arising from distributed generation integration,current differential protection has been increasingly applied in active distribution networks.In distribution feeder sections,T-connected load branches,such as transformers or induction motors,are commonly present.The non-fault transient currents generated by these branches may lead to the maloperation of current differential protection.Focusing on this problem,this paper analyzes multiple scenarios where T-connected transient currents may cause differential protection maloperation.Based on the characteristics of transient current waveforms,a blocking scheme based on the attenuation characteristics of the positive-sequence component of the differential current is proposed.This scheme employs the Fourier algorithm to extract the fundamental current amplitude and distinguishes fault differential currents from non-fault transient differential currents according to the attenuation rate of the positive-sequence current amplitude.Simulation results and field data verification demonstrate that the proposed scheme can effectively avoid the risk of protection maloperation caused by T-connected transformers or induction motors without compromising the sensitivity of current differential protection.