光伏并网发电系统中公共连接点的电压调节

光伏并网发电系统通常应用于薄弱电网末端,输出功率的随机性会造成并网点处电压波动。利用光伏自身无功调节可抑制电压波动。为分析抑制效果,推导出光伏并网发电系统输入电网的有功、无功功率调节范围。当光伏无功调节效果不满足国标要求时,使用超导储能动态电压恢复器(DVR)维持公共连接点(PCC)电压的稳定。采用了PCC电压外环,电容电流内环的双环控制策略,结合空间矢量脉宽调制(SVPWM)对变换器进行控制。仿真结果表明超导储能动态电压恢复器可快速稳定公共连接点电压。

Voltage regulation of the point of common connection in grid-connected photovoltaic generation system

Grid-connected photovoltaic generation system is usually applied to weak system endings, randomness of its output power can cause voltage fluctuation at the point of common connection, that could be restrained by photovoltaic own reactive adjust ability. To analysis inhibition effect, the active and reactive power adjustment range of photovoltaic generation system is deduced. When the deviation of voltage fluctuation goes beyond photovoltaic reactive adjustment ability, superconducting dynamic voltage restorer(DVR) can keep the voltage at the point of common conection(PCC) stabile. A double close-loop control strategy with incorporating inner capacitance current loop and outer system voltage loop is adopted to control converter along with space vector pulse width modulation(SVPWM). Some simulation results are also provided to confirm that the performance of DVR used to photovoltaic generation system can keep quickly the voltage of PCC stable.