光伏电站低电压穿越技术研究

针对大规模光伏电站在电网故障或扰动时突然脱网造成的严重后果,提出了一种光伏电站低电压穿越(Low Voltage Ride Through,LVRT)控制策略,详细分析了基于正负序同步旋转坐标系的并网逆变器控制策略以及LVRT有功电流和无功电流协调控制的实现方法。以单相电压跌落故障为例,进行了仿真和实验研究,结果表明所提出的控制策略不仅能保证并网逆变器在电压跌落期间输出不过流,而且能够向电网发出一定的无功功率以支撑并网点电压的恢复,实现低电压穿越。

Research on Low Voltage Ride Through Technology for Grid-connected Photovoltaic Power Plant

According to the serious consequences caused by large-scale photovoltaic power plant off the grid when grid failure or disturbance taking place, a control strategy based on low voltage ride through of photovoltaic power plant is proposed. The control strategy of photovoltaic grid-connected inverter and the implementation of coordinated control of active and reactive current are analysed detailedly. Then the simulation and experiment are carried out for the single-phase failure. The results verify that the proposed control strategy can ensure the grid-connected inverter output current flow doesn''t overcurrent during low voltage. At the same time, a certain amount of reactive power can be sent to the grid to support the recovery of grid voltage, so as to realize the capability of low voltage ride through.