负荷随机性对网损计算和配电网重构的影响

Influence of Stochastic Loads on Line Loss Calculation and Distribution Reconfiguration

首先分析了考虑负荷随机性情况下的配电网网损计算的特点,指出考虑负荷随机性时的网损期望值通常会大于由负荷期望值计算出的网损。进而以网损期望值最小为目标,使用支路交换法对恒定电流随机负荷情况下的配电网重构方法进行研究,以网损对负荷的有功期望值、无功期望值、有功方差、无功方差的导数确定开关交换对。算例表明,网损期望值最小的重构方案不一定是负荷期望值计算的网损最小的重构方案。该方法对实际配电网重构具有一定的指导意义。

The method for economical reconfiguration of the distribution network is attracting many researchers＇ attention. This paper firstly analyzes the characteristic of line loss calculation with the stochastic loads taken into account. The result shows that considering the stochastic characteristic of loads, the expected value of the line loss is generally larger than that calculated by the expected value of loads. Furthermore, an algorithm based on the branch-exchanging method is proposed to minimize the expected value of the line loss under the condition of stochastic constant current load. The pair of exchanged switches is determined by the differential coefficient of line loss to the expected value of active power, reactive power, active variance and reactive variance. Test results indicate that by considering stochastic loads the optimal reconfiguration scheme of minimal expected value of line loss is not always the same as that of minimal line loss. The proposed method is instructive for actual reconfiguration in a distribution network.