基于PMU的配电网状态估计

State estimation of distribution network based on PMU

分布式能源的接入、网络结构的复杂性以及量测数据冗余不足,使配电网状态估计的精度较低。针对量测数据精度不高的问题,引入同步向量测量装置(Phasor Measurement Unit,PMU)以提高状态估计的精度;针对配电网状态估计中应用最多的加权最小二乘法(Weighted Least Squares,WLS)对量测数据精度要求高、抗差能力差的缺点,结合Huber算法和多目标函数抗差估计算法改进了加权最小二乘法,提出三目标函数型预抗差状态估计。通过对迭代次数的判断并结合WLS、Huber算法和指函数型目标函数的优点确定选用哪种目标函数。算例分析在IEEE33节点系统中展开,结果表明,加入PMU有效提高了量测数据的准确性。三目标函数预抗差算法比WLS估计精度高、抗差性强,验证了所提算法的有效性。

The accessibility of distributed energy,the complexity of the network structure,and the insufficient or redundant data make the state estimation of the distribution network inaccurate. Aiming at the low accuracy of measurement data,the Phase Measurement Unit( PMU) was introduced to improve the accuracy of state estimation. In view of the shortcomings of Weighted Least Squares( WLS) which is the most widely used method in the state estimation of distribution network,such as high accuracy and poor tolerance of measurement data,this paper improved the WLS method by combining Huber algorithm and multi-objective function robust estimation algorithm,and proposed three-objective function type pre-difference state estimation, mainly by judging the number of iterations and combing the advantages of the WLS,Huber algorithm and the exponential objective function to determine which objective function to use. The case study was carried out in the IEEE-33 node system. The results proved that the addition of PMU effectively improves the accuracy of the measured data. The three-objective function pre-difference algorithm is more accurate and robust than WLS estimation,which verifies the effectiveness of the proposed algorithm.