地铁功率波动的概率分布特性分析

Probability distribution characteristic analysis of metro power fluctuation

地铁是重要的城市用电负荷,地铁功率的随机波动会造成城市电网的电压波动等问题。基于地铁供电系统等值电路,分析了地铁功率波动的机理,根据实测的地铁功率波形,采用滑动平均法分离出地铁功率的min级波动分量,选择t location-scale分布、Logistic分布、正态分布以及极值分布,对地铁主变电站的典型日功率曲线、季度功率曲线min级波动分量的概率密度函数进行了拟合,最终得到其概率分布特征。结果表明,地铁功率波动主要集中在行车时段,而在夜间休车时段波动较小。地铁功率的波动分量一般可近似用t location-scale分布来描述;而在个别出现电压闪变超标的日期,Logistic分布、正态分布具有更好的拟合效果。

Metro is an important urban power load,and the random fluctuations of the metro power will cause power grid voltage fluctuations of city and other issues.Firstly,based on the equivalent circuit of the metro power supply system,the mechanism of the metro power fluctuation is analyzed.Then,according to the measured metro power waveform,the moving average method is used to separate the minute-scale component of metro power.After that,t location-scale distribution,logistic distribution,normal distribution and extreme value distribution are chosen to fit the minute-scale component of the main metro substation power,which contain daily power curve and quarterly power curve.Finally,the probability distribution characteristic is obtained.The results show that the power fluctuation of the metro is mainly concentrated in the driving time,while it is small in the break time at night.The fluctuation component of the metro power can be approximately fitted by the t location-scale distribution,and the fitting effect of logistic distribution and normal distribution is better only when the voltage flicker exceeds the standard.