基于等值建模的大型光伏电站接入电网后暂态稳定性

Transient Stability of the Large-Scale Photovoltaic Power Plants Connected to Power Grid Based on Equivalent Model

随着光伏产业的快速发展,研究光伏电站并网仿真模型具有重要意义。建立了适用于西北光伏工程的光伏电池工程实用模型,该模型适用于任意温度T和任意光照强度S。以海西电网2014年底网架和运行方式为基础,深入分析了光伏电站接入后电网暂态稳定特性的变化。结果表明,当光伏电站不具备低电压穿越能力时,会引起海西地区大部分甚至全部光伏电站脱网,但系统能够维持稳定运行;当光伏电站具备低电压穿越能力,能显著降低系统运行风险。

With rapid development of the photovoltaic（PV）researches on the model of the grid-connected PV system are increasingly important. In this paper the photovoltaic cell engineering model for PV projects in Northwest China is established and this model is suitable for arbitrary temperature T,arbitrary illumination intensity of S（the supplier can provide the technical parameters. Based on the operating mode and structure of Haixi grid in 2014,this paper presents an in-depth analysis of the power flow characteristics,static voltage and the change of transient stability after the PV plant is connected to the power grid. The results show when photovoltaic power plants do not have the capability of low voltage ride through,most or even all the photovoltaic power plants would be cut off the power grid, however, the system operation still maintains stable. If photovoltaic power plants have low voltage ride through capability,the operating risk can be reduced significantly.