配电网线损计算中等效容量法的局限及改进

Limitation and improvement of the equivalent capacity method for calculating the energy loss of distribution networks

通过配电网线损计算中等值电阻法的分析研究,指出当存在小电源并使馈线首端出现功率倒送或功率方向动态改变时,用传统的等效容量法处理小电源会导致很大的线损计算误差。针对这一局限,提出了改进方法,即不再基于日均方根电流使用单一等值电阻,而把1天分为功率方向不变的若干时段(如24 h),分别计算出各时段的等值电阻和电能损耗,再叠加各时段的电能损耗可得出1天的总损耗。经算例计算证明改进方法对提高计算精度十分有效。

Through the analysis of the equivalent resistance method, a limitation of the equivalent capacity method was presented. When the direction of power at the feeder source end was changing, the equivalent capacity method for handling small generations would produce a large power loss calculation error. An improved calculation method, one not based on a single equivalent resistance, was proposed. In this method, one day was divided into several periods （such as 24 h）, so that the direction of power at the feeder source end for were calculated. The were used to verify th each period does not vary. The equivalent resistance and energy loss in each period sum of all energy losses provided the daily energy loss total. Numerical examples e improved method.