配电光伏网并网逆变器电压控制策略研究及其实现

Research and Implementation of Voltage Control Strategy for Grid-connected Photovoltaic Inverter

为了降低光伏出力提高后易引起并网点电压超过上限的问题,提出了一种光伏并网逆变器并联时电压功率控制策略,并进行仿真实现分析。测试各光伏并网逆变器在并网过程中形成的电压与电流,再利用线路阻抗测试的方法分析线路1和传输线路2之间形成的线路阻抗,以此满足各分布式光伏电源保持并网运行的条件。仿真分析结果得到,在0.1 s以内时,二个并联逆变器按照功率均分的形式达到负荷的并网运行过程;到达0.1 s时,系统出现电流扰动的现象,从0.3 s开始各项参数重新转为正常状态;进入0.4~0.6 s之间时,线路1和2都达到了2.15-j0.5 kV·A的输出功率,网点线达到406 V的有效电压,符合电压偏差条件。

In order to reduce the problem that the voltage of grid connection points exceeds the upper limit which is coursed by the increase of photovoltaic output,a voltage and power control strategy is proposed for the case that photovoltaic grid-connected inverter is connected in parallel,and the simulation implementation is analyzed.The paper also tests the voltage and current formed duringthe grid-connection of various grid-connected photovoltaic inverters,and analyzes the line impedance formed between line 1 and transmission line 2 by usingthe method of line impedance test,so as to meet the requirements for maintaininggrid-connection operation of various distributed photovoltaic power supplies.Simulation results show that,within 0.1 s,two parallel inverters reach the grid-connected operation process of load in the form of power sharing.When it reaches 0.1 s,the system will be disturbed by current,and all parameters will return to normal state at 0.3 s.When enteringperiod between 0.4 s and 0.6 s,the output power of line 1 and line 2 reaches 2.15-j0.5 kV·A,and the net point line reaches the effective voltage of 406 V,which conforms to the voltage deviation condition.