环网配电网络电压暂降分析的临界比距法

基于临界距离法原理,提出馈线临界比距的概念,针对几种环网配电网络,讨论了馈线临界比距的计算方法,根据馈线临界比距的数值可分析各出线故障对公共连接点 (point of common coupling,PCC)电压暂降的影响程度以及快速确定导致PCC点严重电压暂降的输电线路。与临界距离法相比,临界比距法避免了临界距离超出线路长度的情况,在确定电压暂降暴露域时物理概念更加清晰。估算结果与实际测量结果的比较证明了该方法的有效性。

Critical Percentage Method of Meshed Distribution Networks for Voltage Sag Analysis

Based on the principle of critical distance method, a concept of critical percentage is proposed and the calculation of critical percentage is researched to several meshed distribution networks. The value of feeder's critical percentage can be used to analyze the influence of the fault occurred in each outlet on voltage sag at the point of common coupling (PCC), thus the transmission line that causes serious voltage sag at PCC can be rapidly determined. Compared with critical distance method, the situation that the critical distance exceeds the length of transmission line can be avoided while critical percentage method is applied. When critical percentage method is used to determine voltage sag exposed area, the physical conception will be clearer. The effectiveness of critical percentage method is proved by the comparison of estimation results with measured results.