含分布式电源配电网的短路电流计算方法研究

Short-Circuit Current Calculation of Distribution Network With Distributed Generation

分布式电源接入配电网将对配电网的短路电流水平产生一定的影响。基于电机型和换流器型分布式电源的短路电流特性,得到分布式电源在配电网发生短路时的等效模型。将包含分布式电源在内的所有电源处理为故障电流源,将故障网络分解为正常分量网络和故障分量网络,按照节点电压方程分别计算短路电流的正常分量和故障分量,可得到不同短路类型下的短路电流。通过示例系统仿真结果的对比分析,验证了所提方法的有效性。该方法可应用于大规模配电网络短路电流的计算机求解。

The distributed generation integration to the distribution network would have some influences on short-circuit current level. According to the short-circuit current characteristics of the generator-based distributed generation and inverter-based distributed generation, their equivalent circuit during the short-circuit has been obtained. All of the power sources including the distributed generation should be substituted with equivalent current sources, and the fault equivalent circuit should be decomposed into a normal component network and a fault component network. The normal component and fault component of the short-circuit current can be calculated with the node voltage equations, and then any case of fault current in the distribution network can be solved with this method. Through comparison with and analysis of the testing results on a typical system, it is shown that the proposed method is efficient and accurate. This method can be applied to short-circuit current calculation of large-scale distribution network with computer.