当具有一定规模的光伏电站接入区域电网的某一节点后,由于电网和光伏电站运行特性的不确定性,导致电网与光伏电站间产生复杂的相互影响,对并网点电压故障的诊断造成困难.针对该问题,文章提出了基于光伏电站并网点两侧等值阻抗模对比的并网点电压故障在线诊断模型.在考虑光伏电站侧和电网侧等值阻抗模测量不确定性的前提下,基于阻抗模模型建立了并网点电压故障鲁棒M估计在线判别模型;在阻抗模测量尺度的鲁棒标准化基础上,建立了电网侧与电站侧阻抗模差值的鲁棒M估计模型.根据两侧阻抗模的实时测量值,给出了阻抗模测量时刻的最优阻抗模差值判据,并以此为光伏电站并网点电压故障诊断判据.文章建立10机39节点仿真模型并进行仿真计算,仿真结果验证了所提出的基于阻抗模的并网点电压故障鲁棒在线诊断模型的有效性.%When a large-scale PV power station is connected to a node of regional power grid, there will be complex interaction between the power grid and the PV power station due to the uncertainties of the power grid and the PV power station operation, thus causing difficulties to the voltage fault diagnosis. For solving this problem, an on-line grid-connected point voltage fault diagnosis model based on the comparison of equivalent impedance modes on both sides of the grid-connected point of PV power station was presented in this paper. Considering the uncertainties of equivalent impedance module measurement on PV power station side and grid side, an on-line robust M-estimation discrimination model for voltage fault of grid-connected point was established based on impedance model; the robust M-estimation model of impedance difference between grid side and station side was established based on the robust standardization of impedance module measurement scale; according to the real-time measured values of impedance modules on both sides, the optimal impedance modulus difference criterion at the measuring moment of impedance module was given for voltage fault diagnosis. The simulation results of the 10-machine's 39-node simulation model established in this paper demonstrated the validity of the on-line robust diagnosis model for grid-connected point voltage fault based on impedance model.
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