适用于含新能源逆变电源网络的全时域短路电流计算方法

Full-time domain short circuit current calculation method suitable for power network with inverter-interfaced renewable energy source

含新能源逆变电源在故障后无恒定电动势,因而传统交流网络短路电流计算所用的内电动势-阻抗方法不再适用。为解决该问题,提出了一种包含新能源逆变电源故障稳态和暂态2种时间尺度下的全时域短路电流计算方法。故障稳态计算中结合逆变电源的控制策略,将逆变电源视为非线性电流源,充分反映了逆变电源短路后的故障特性。故障暂态计算中基于稳态短路电流结果,利用由控制系统推演出的暂态微分方程,求解出暂态过程中的电流表达式。最后将计算值和仿真结果、录波结果进行对比,验证了该方法的可行性。

The inverter-interfaced renewable energy source has no constant electromotive force after fault,so the internal electromotive force-impedance method used in the calculation of short circuit current of conventional AC network is no longer applicable. To solve this problem,a full-time domain short circuit current calculation method including fault steady state and transient state of the inverter-interfaced renewable energy source is proposed. In combination with the control strategy of the inverter-interfaced source during the calculation of fault steady state,the inverter-interfaced source is regarded as a nonlinear current source,which fully reflects its fault characteristics after short circuit faults. Based on the steady state short circuit current results,the current expression in the transient process is solved by the transient differential equation derived from the control system. The feasibility of the proposed method is verified by the comparison among the calculated values,the simulative results and the recording results.