多个电气用户共用交流输电路径时,能否正确计算各自对输电路径的使用份额系数,关乎电力系统许多技术和经济问题的客观公正解决。然而,该问题目前尚未取得达成共识的解决方法。经重新审视发现,现有方法的研究思路普遍基于交流电路有关物理量的平均值、从相量分析的角度构造电气份额(electrical share,ES)计算关系,该思路可能从一开始就为方法存在理论缺陷埋下了隐患。文中回归到从交流电路瞬时值角度探讨问题的解决之道:先由交流电气用户和输电路径上的瞬时功率或瞬时电流的实际分布(包括方向和数值)情况,定义瞬时ES系数,再对瞬时ES系数求特定时间周期内的平均值。先求待研究物理量的瞬时值再求其平均值的计算方式,符合对任意连续时间过程相关物理量的一般评估思路。在此基础上,针对交流输电路径受端节点联接等效负荷用户(或送端节点联接等效电源用户)、送端节点联接电源和负荷用户、受端节点联接电源和负荷用户几种方式,给出了不同用户使用输电路径的瞬时ES系数和平均ES系数解析计算关系。理论检验和数值算例对比分析结果表明,源于瞬时值解析得出的ES系数计算方法,更具理论正确性,有可能尽早使问题取得共识性成果。
The correct calculation of multi-electrical-user's share coefficients on the AC transmission line is about the objective and fair solutions for many power system's technical and economic issues. However, the problem has not yet reached a consensus on computation method. This paper reviewed and found that the research ideas of the existed methods were generally based on the mean values of AC circuit physical quantities and established calculation formula of electrical shares from the phasor analysis. These ideas might store up method's theoretical defect from the start. This paper returned to probe into solution of problem from the AC circuit instantaneous value. Firstly, defined instantaneous electrical share (ES) coefficients of AC transmission line according to the actual direction and magnitude distributions of electrical-user's and transmission line's instantaneous powers or currents. Secondly, calculated the mean values of instantaneous ES coefficients for a specific period of time. The way of calculating the mean value after calculating the instantaneous value of a studied physical quantity conforms to the general assessment idea for relevant physical quantities with arbitrary continuous time processes. Based on the above analysis, this paper derived analytical formulas of instantaneous and mean ES coefficients of transmission line for different connected- mode users such as receiving-bus equivalent load users, sending-bus equivalent source users, sending-bus equivalent source and load users, and receiving-bus equivalent source and load users. Theoretical proof and numerical comparative analysis show that the calculation method of ES coefficients from instantaneous value analysis is of more theoretical correctness, and there can be as early as possible for obtaining the consensus results.