Ground fault protection method and apparatus for photovoltaic station output transmission line

A ground fault protection apparatus for a photovoltaic station output transmission line, wherein the photovoltaic station output transmission line comprises an output transmission line on a power grid side and an output transmission line on a photovoltaic side, and wherein the apparatus comprises a first control element, a second control element, a first circuit breaker and a second circuit breaker;

• wherein the first circuit breaker is disposed on the photovoltaic side, the second circuit breaker is disposed on the power grid side, the first control element is electrically connected to the first circuit breaker, and the second control element is electrically connected to the second circuit breaker;
• the second control element is configured to configure setting impedance and an operation time limit on the power grid side, and in condition that a ground fault happens to the photovoltaic station output transmission line, start power grid side distance protection;
• the first control element is configured to perform a setting process on the photovoltaic side according to a setting value of a variation of measured zero sequence impedance, determine whether an operation condition of a photovoltaic side protection position is satisfied, determine whether to start photovoltaic side distance protection, and adjust protection starting time on the photovoltaic side;
• the first circuit breaker is configured to trip in condition that the photovoltaic side distance protection is started;
• and
• the second circuit breaker is configured to trip in condition that the ground fault happens to the photovoltaic station output transmission line.