大功率电解整流系统背景谐波建模及谐波责任评估

Background harmonic modeling and harmonic contribution assessment for large-power industrial supply system

大功率电解整流系统向电网排放大量谐波,严重影响并网点电能质量,建立精准的电网背景谐波电压模型并对谐波责任进行评估有利于衡量电力用户谐波排放对公用电网造成的影响程度.本文基于某电解锰厂实测数据,首先介绍了被测工厂供电背景和电网公共连接点谐波电压分布规律;进一步地,分别采用正态分布、对数正态分布和Weibull分布函数对特征停产日的分时段谐波电压概率分布进行拟合,利用Kolmogrov-Smirnov检验方法获取的拟合优度辨识出最优拟合函数,建立停工日背景谐波电压仿真模型;最后,根据该谐波电压概率分布模型对生产日的电解车间在公用电网母线上的谐波责任进行评估,分析结果表明:所测试的电解厂对公用电网的谐波责任以负向贡献为主.

The large-power rectifier system injects numerous harmonics into the public grid, which results in serious effects on the power quality at the point of common coupling(PCC). The two methods,(1) establishment of the accurate probabilistic model for the background harmonics and(2) assessment of the harmonic contribution, are beneficial for evaluating the impact of the harmonics generated by the power consumer on the power grid. First, the background of the power supply system and the harmonic distribution at the PCC are introduced, based on the measured data in the electrolytic manganese factory. The probability distribution of the harmonic voltage during the specific discontinued day is fitted by means of the normal distribution, the lognormal distribution and the Weibull distribution. The goodness-of-fit is obtained by Kolmogrov-Smirnov test method, and the optimal fitting function is identified. The simulation model of the background harmonic voltage is thus built. Finally, the harmonic contribution of the rectifier system on the production day is assessed based on the simulation model. The results show that, the negative harmonic contribution is dominating.