少环配电网短路故障计算新方法

A New Method for Short Circuit Fault Calculation of Weakly Meshed Distribution Networks

通过网络变形,构造出对环网解环及短路故障进行模拟的新端口,给出了环网解环及短路故障模拟的统一方法。以新端口为边界,将故障后的少环配电网分解成辐射状对称网络和模拟环网解环及短路故障的不对称网络2部分。在此基础上,推导了边界端口注入电流的计算公式;基于辐射状网络节点注入电流、支路电流及节点电压间的关联关系,完成了非故障处支路电流、节点电压的计算,提出一种少环配电网短路故障计算的新方法。该方法具有以下特点:环网解环及短路故障的模拟方法统一,可以方便地模拟任意复杂故障,包括两点接地故障;利用辐射状网络的支路阻抗参数完成故障计算,故障计算效率高;能够自动适应网络操作;非故障处的支路电流、节点电压的计算简单直观。算例分析表明,该算法具有良好的计算效率和精度。

By changing the network, the new ports are constructed and a unified method is given to simulate loop-opening and short circuit faults. At the new port boundary, the faulted weakly meshed network is divided into two networks, i.e. the pure radial symmetrical network and the unsymmetrical network to simulate loop-opening and short circuit faults. Then the short circuit current and the compensation current calculation formulas are obtained. According to the relationship among branch current, nodal injection current and nodal voltage, the branch current and nodal voltage calculation method is given. A new method to calculate weakly meshed distribution network short circuit faults is presented. It has the following characteristics： （Ⅰ） a unified and simple loop-opening and short circuit fault simulation method capable of simulating any kinds of faults easily including double-point-to-earth fault; （Ⅱ） a highly efficient fault calculation algorithm based on the branch impedance parameters instead of node impedance parameters; （Ⅲ） adaptive to network topology change; （Ⅳ） easy and direct calculation for the faultless branch current and node voltage. Case study results demonstrate that the proposed algorithm has good computational efficiency and accuracy.