作　　者： (李江）; (魏文震）; (陈继开）;

机构地区： 东北电力大学电气工程学院,吉林吉林132012

出　　处： 《南方电网技术》 2017年第7期58-67,共10页

摘　　要： 配电网受谐波和噪声干扰严重,电压相量的计算难度更大,传统的输电网相量测量精度不能满足配电网的要求。为提高配电网电压相量幅值和相角的测量精度,提出了一种基于条件最大似然估计法(conditional maximum likelihood estimation,CML)的配电网微型同步相量测量单元(μPMU)的相量测量方法。该算法建立了三相不平衡系统的信号模型,在待测量最多包含两个未知量且待测量矩阵与单位矩阵正交不等于零时,利用三相矩阵与样本协方差矩阵的特征向量正交来获取待测量,进而通过几何特性推导出电压相量的幅值及相位表达式,降低了运算量。通过Matlab进行了仿真验证,仿真结果表明所提方法能够在一定程度上提高配电网电压相量幅值和相位的测量精度。 Distribution network is seriously affected by harmonics and noise, the calculation of voltage phasor is more difficult, and the traditional phasor measurement accuracy of power transmission network can not satisfy the demand of distribution network. In order to improve the measurement accuracy of voltage amplitude and phase angle of distribution network, a method based on conditional maximum likelihood estimation （CML） is proposed for measuring the phasor of micro-synchronous phasor measurement unit （μPMU） in distribution network. The algorithm establishes the signal model of three-phase unbalanced system. When the measurement is up to two unknowns and the orthogonal value of the measured matrix and the unit matrix is not equal to zero, the feature which the three- phase matrix is orthogonal to the eigenvector of the sample covariance matrix is used to obtain the measurement. Furthermore, the am- plitude and phase expression of the voltage phasor are deduced by the geometric characteristic, which reduces the computational com- plexity. Simulation test is carried out by Matlab, and the simulation results show that the proposed method can improve the measure- ment accuracy of the voltage amplitude and phase angle of distribution network to a certain extent.

关 键 词： 配电网 三相不平衡系统 条件最大似然估计