分布式光伏发电并网系统电压稳定性研究

Study of Voltage Stability for Distributed Photovoltaic Grid-connected System

鉴于分布式光伏发电并网系统的电压稳定性对现实生活有重要意义,从工程角度给出380/220V低压配电网电压失稳的实用判据,运用PSCAD软件构建了一个分布式光伏电源接入0.4kV配电网的3节点系统仿真模型,在此基础上分析了负荷增加、光照强度突降、环境温度增大以及负荷母线发生短路故障等扰动对负荷电压稳定性的影响。仿真结果表明,当负荷电压接近电压稳定限定值正常运行时,光照强度突降会使负荷母线电压失去稳定;温度变化对负荷电压的影响甚微;短路故障消除后负荷母线电压则能够快速得到恢复,不会导致电压失稳。

The voltage stability of distributed photovoltaic generation system has a significant role in actual life.The practical criterion of voltage instability for the 380/220Vlow-voltage distribution network was discussed from the viewpoint of engineering.The PSCAD software was used to build a 0.4kV 3-bus distributed network simulation model containing agrid-connected distributed photovoltaic power.On that basis,the influences on the load voltage stability were analyzed by considering various disturbances,such as the growth of load,sudden reduction of light intensity,rise in environmental temperature and the short circuit fault of the load bus.Simulation results show that when the load voltage is approaching the limit of voltage stability,the sudden reduction of light intensity will make the load bus voltage lose stability while the influence of temperature change is very tiny;the load bus voltage will recover the original value quickly after the short circuit fault is eliminated and it will not lose its stability.