A Protection Scheme Based on Positive Sequence Fault Component for Active Distribution Networks

摘要

With the high penetration of distributed generations (DGs), the conventional radial distribution network is becoming an active distribution network (ADN). In general, DGs can be divided into two types: rotating type distributed generations (RTDGs) and inverter-interfaced distributed generations (IIDGs). Compared with RTDGs, the fault characteristics of IIDGs are more complex. This will reduce the reliability and sensitivity of traditional overcurrent protection. To provide effective protection for active distribution network, a novel protection scheme based on positive sequence fault component (PSFC) of current is proposed in this paper. This scheme uses the amplitude ratio of PSFC at the two ends of the protected line as the operating quantity, and uses the phase difference of PSFC to construct the threshold. This scheme fully reflects the advantages of PSFC, such as reflecting all types of faults, not affected by the load, sensitive under the condition of high resistance fault. Finally, a simulation modeling based on PSCAD is set up to verify the feasibility of the proposed protection scheme.