计及故障距离的配电网单相接地有源消弧法

Active Arc-suppression Method for Single-phase-to-ground Fault of Distribution Network Considering Fault Distance

传统有源消弧法通过控制母线处故障相电压实现消弧,由于故障线路上存在电压降落,故障点电压与母线测量点电压存在偏差,难以实现可靠消弧。本文提出了一种基于故障距离估计的有源消弧方法,采用二分法估计故障距离,计算合适的参考电压,根据故障距离估计值和负荷阻抗调整逆变器参考电压,通过逆变器跟踪参考电压实现对故障电流和恢复电压的抑制,有效消除线路电压降落给消弧带来的影响。PSCAD/EMTDC仿真结果表明,该方法能有效抑制故障电弧,具有可行性。

The traditional active arc-suppression method controls the bus voltage in the fault phase to realize arc suppression.However,due to the voltage drop on the fault line,there is difference between the voltage at the fault point and the bus voltage at the measurement point.Therefore,it is difficult to realize arc suppression reliably.In this paper,an active arc-suppression method based on fault distance estimation is proposed.The fault distance is estimated using the bisection method,and the proper reference voltage is calculated.The reference voltage of the inverter can be adjusted according to the estimated fault distance and load impedance,and the reference voltage is traced through the inverter to realize the suppression of fault current and recovery voltage,thus eliminating the effects of voltage drop on arc suppression.The simulations based on PSCAD/EMTDC show that the proposed method can effectively suppress the fault arc and that it is feasible.