Quick junctor fault isolation method compatible to low-voltage ride through operation of photovoltaic power station

The invention relates to a quick junctor fault isolation method compatible to the low-voltage ride through operation of a photovoltaic power station, which belongs to the field of grid connection in the power generation of new energy resources. According to the method, the side of a grid-connected distribution substation of a photovoltaic power station is configured with a traditional two-section type current protection element (I-section current quick-break protection and II-section over-current protection) and an opposite-end direct-trip protection element, and the two-section type current protection element is used for judging whether a fault is an internal fault or not according to the after-current measurement value of the fault; if the fault is the internal fault, the operation of trip is carried out on an outlet; meanwhile, a trip signal is sent out to the protection of the opposite ends of a line (the side of the photovoltaic power station) by the opposite-end direct-trip protection element; and the side of the photovoltaic power station is configured with a low-voltage harmonic distortion rate quick fault starting element and a direct-trip protection element, an outlet circuit of a protection device is opened after the occurrence of the fault is judged by the low-voltage harmonic distortion rate quick fault starting element, and the action of the trip signal sent by the protection of the opposite ends is received by the direct-trip protection element for carrying out the trip of the outlet. According to the method disclosed by the invention, the quick detection and isolation of the fault of a junctor of the photovoltaic power station can be realized under the precondition that the low-voltage ride through requirement of an electric power system is effectively ensured; and the effective compatibility of the anti-islanding protection to the low-voltage ride through operation of the photovoltaic power station can be realized.