LOW VOLTAGE RIDE THROUGH DETECTION DEVICE FOR GRID-CONNECTED PHOTOVOLTAIC INVERTER

The present invention relates to a low voltage ride through detection device for a grid-connected photovoltaic inverter. The device comprises a current-limiting inductor, a short-circuit inductor, and a grounding combined switch. The current-limiting inductor, an intermediate inductor-circuit breaker unit, a short-circuit inductor, and a grounding combined switch are sequentially connected in series. The current-limiting inductor is connected to a 10/35kV power grid. The intermediate inductor-circuit breaker unit and the grounding combined switch are connected to a neutral point at a high voltage side of a step-down transformer, respectively. The step-down transformer is connected to the grid-connected photovoltaic inverter. While guaranteeing that the short-circuit capacity is not changed, the detection device changes the ratio of current-limiting and short-circuit inductors through different switching modes of several circuit breakers, thereby meeting the requirement of low voltage ride through detection at