计及LVRT控制策略的光伏电站并网配电网故障分析方法

Failure Analysis Method in Distribution Network Considering LVRT Control Strategy of Grid-connected Photovoltaic Station

随着光伏电站在配电网中渗透率的不断提高,且在光伏电站低电压穿越(LVRT)控制特性的要求下,诸多故障分析方法已经不再适用。针对上述问题,首先通过分析光伏电站故障电流输出特性建立受并网点正序电压控制的电流源等值模型;在此基础上,分析在不同故障条件下含光伏电站的配电网节点电压方程,针对光伏电站输出电流与并网点正序电压间的非线性关系,提出双端搜索下的试根法配电网故障分析方法。最后,通过仿真验证算法的准确性,并比较光伏电站在LVRT控制策略与传统控制策略下配电网的故障特性,验证LVRT控制特性在故障时对电网的支撑作用。

With the penetration of photovoltaic（PV）station in the steady improvement and the low voltage ride-through（LVRT）of the PV station,lots of failure analysis is no longer suitable for use.For this reason,an analysis is made of the failure output characteristics of the PV station prior to development of the current source equivalent model controlled by the positive sequence voltage of the point of common coupling.Secondly,the node voltage equations under different fault conditions are analyzed and the test root method is proposed under the double-ended search method by the nonlinear relationship between the output current of PV station and positive sequence voltage by different types of faults.Lastly,the accuracy of the algorithm is verified by comparing the results with the simulation results while the failure characteristics are compared between LVRT and traditional control strategies to verify the supporting role in LVRT control.