配电网三相潮流的简化分析

Simplified approach to three-phase power flow calculation of distribrtion networks

为了减少配电网三相潮流分析的计算量,提出了配电网的三相双方向等效电压降落模型,该模型考虑了互阻抗参数的影响,把馈线段上所有的三相负荷用一个三相等效负荷表示,然后使采用简化模型得出的馈线段端部的电压降落与未简化馈线模型计算的电压降落相等,令简化后馈线段总阻抗与简化前总阻抗相等,并利用配电网的馈线段沿线电压幅度和相位变化不大的特点,推导出双方向等效电压降落模型中的各项参数,该模型确保了在馈线段相互连接构成配电网络后,仍能得到精确度很高的馈线段端点电压的计算结果。在此基础上进一步提出了计算馈线段上各个负荷点处的三相电压和各支路线损的递推公式。文中给出了一些算例,并与严格潮流计算方法进行了比较,结果表明提出的简化方法的近似精度高,并且在应用到基于遗传算法和模拟退火算法等随机优化算法的配电网络重构时,可大大提高潮流计算效率。

To reduce calculation of three-phase power flow of distribution networks, a three-phase Bilateral equivalent Voltage Drop Model （T-BVDM） is suggested. The influence of mutual impedance is considered. The total three-phase loads on one feeder are simplified by an equivalent load. The voltage drops on two terminals and the total self-impedances of the feeder remain unvaried before and after using the T-BVDM. Different parameters of T-BVDM are obtained. The accuracy of feeder terminal voltage calculation is guaranteed even when the feeders connecting with each other to form a grid. The method to calculate the three phase voltages on each load position and the loss of each branch is deduced based on the results ofpower flow analysis by T-BVDM. Some examples are given. Results of this method are compared with those of the power flow analysis without simplification. It shows that this method is valid.