并网光伏电站低电压穿越仿真与分析

根据光伏电站并网导则要求,针对光伏电站在电网故障时突然脱网的不利影响,提出了一种基于光伏逆变器低电压穿越能力的控制策略,在电网电压跌落时投入该控制策略,能够限制有功电流的增大,同时给定无功电流。仿真表明,在光伏电站并网点电压深跌落和浅跌落情况下,该控制策略均能够保证光伏逆变器输出电流不过流,同时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。

The Simulation and Analysis on Low Voltage Ride Through of Grid-connected Photovoltaic Power Station

Based on the guide requirements of grid-connected photovoltaic power station, a control strategy based on low voltage ride through capability of the PV inverter is proposed for the adverse effects caused by photovoltaic power station off the grid when power failure taking place. The increase of active current can be limited, and the reactive current can be given through putting into the control strategy when the power grid voltage drops. Simulation results show that in the case of network voltage dropping deeply and shallowly at the grid-connected point of photovoltaic power station, the control strategy can ensure that the PV inverter output current flow doesn＇t overcurrent. At the same time, a certain amount of reactive power can be sent out to the grid to support the recovery of voltage at the grid-connected point and achieve tow voltage ride through.