摘要
为精准估计光伏直流微电网故障电流参数,提升故障电流过零点预测效果,提出一种基于加权最小二乘法(weighted least squares,WLMS)算法的光伏直流微电网故障电流过零点预测方法。通过故障电流参数来估计误差平方加权值与幅度因子,确定WLMS算法内步长因子的取值范围,改进WLMS算法;利用改进WLMS算法来估计故障电流参数,并依据该结果建立光伏直流微电网故障电流模型;先通过F0假设检验方法在模型内提取故障电流初始相角,再通过调整采样数据窗,令建立的故障电流模型和实际模型相同,则当故障电流初始相角超过设定阈值时,可利用该模型来预测故障电流过零点。实验结果表明:所提方法下,光伏直流微电网故障电流估计的时间常数和初始电压相角与实际结果非常接近,最大误差分别为3 ms和8°;不同故障时,均有效预测了故障电流过零点,准确率为100%;在故障电流内添加谐波后,预测过零点的稳态误差较低,最高稳态误差低于24 A。
To accurately estimate the fault current parameters of photovoltaic DC microgrids and improve the prediction effect of fault current zero-crossing points,a method for predicting the zero-crossing points of fault currents in photovoltaic DC microgrids based on the weighted least squares(WLMS)algorithm is proposed.The error square weighted values and amplitude factors are estimated through fault current parameters,the value range of the step factor in the WLMS algorithm is determined,and the WLMS algorithm is improved.The improved WLMS algorithm is used to estimate the fault current parameters,and based on the results,a fault current model of the photovoltaic DC microgrid is established.First,the initial phase angle of the fault current is extracted from the model using the F0 hypothesis testing method,and then by adjusting the sampling data window,the established fault current model is made consistent with the actual model.When the initial phase angle of the fault current exceeds the set threshold,this model can be used to predict the zero-crossing point of the fault current.Experimental results show that with the proposed method,the time constant and initial voltage phase angle estimated for the fault current of the photovoltaic DC microgrid are very close to the actual results,with maximum errors of 3 ms and 8°respectively;under different faults,the zero-crossing points of the fault current are effectively predicted,with an accuracy of 100%;after adding harmonics to the fault current,the steady-state error of predicting the zero-crossing points is low,and the maximum steady-state error is less than 24 A.
作者
钟锦星
孔慧超
吴新雄
王凯亮
黄学劲
ZHONG Jinxing;KONG Huichao;WU Xinxiong;WANG Kailiang;HUANG Xuejin(Dongguan Power Supply Bureau of Guangdong Power Grid Co.,Ltd.,Dongguan 523000,Guangdong,China)
出处
《电网与清洁能源》
北大核心
2025年第8期66-72,82,共8页
Power System and Clean Energy
基金
中国南方电网有限责任公司科技项目(2020T201A01)。
关键词
WLMS算法
光伏直流
微电网
故障电流
过零点预测
步长因子
假设检验
WLMS algorithm
photovoltaic DC
microgrid
fault current
zero crossing prediction
step size factor
hypothesis test
作者简介
钟锦星(1987-),男,硕士,工程师,研究方向为智能电网规划;孔慧超(1980-),女,硕士,高级工程师,研究方向为智能电网规划;吴新雄(1990-),男,本科,工程师,研究方向为智能电网规划;王凯亮(1988-),男,硕士,工程师,研究方向为智能电网规划;黄学劲(1987-),男,硕士,高级工程师,研究方向为智能电网规划。
