Fault phase selection method for high voltage transmission line of high proportion renewable energy system

In the high-proportion renewable energy source grid (HP-RES grid), the nonlinear controlled characteristics of renewable energy sources, make the fault characteristics of power grid more complex, which deteriorates the performance of traditional phase selection components of high-voltage transmission lines. Based on the engineering practice of typical HP-RES grid, this paper analyzes the adaptability of traditional phase selection methods under different operation modes of the system. On this basis, a fault phase selection method adapted for high voltage transmission line of HP-RES grid is proposed. The method combines the voltage amplitude and variation comparison to identify single-phase fault and multi-phase fault based on the instantaneous value integral algorithm. The single-phase fault identification and faulty phase selection are carried out by using the proportional relationship between the intermediate value and the minimum value of the measurement phase voltage, and the multi-phase fault phase identification and faulty phase selection is carried out by using the amplitude of the measurement line voltage. Considering the large short-circuit current in large operation mode as the factor, the fault phase voltage value will be increased to a great extent in the case of fault resistance. In order to prevent the phase selection error, the single-phase fault selection is carried out by using the phase type and proportional relationship between the maximum value of phase compensation voltage variation and the minimum value of phase-phase compensation voltage variation when the above single-phase selection criterion fails. The simulation results show that the proposed fault phase selection method is not affected by the power source type, suitable for weak power source side and can correctly select faulty phase under different operation modes of HP-RES grid, which has high reliability and sensitivity.