A zero-crossing point prediction algorithm of short-circuit current for mine-used phase-controlled switching

The existing zero-crossing point prediction algorithms of short-circuit current have some problems, such as complex calculation and big error. For three-phase short-circuit fault of coal mine power supply system, a zero-crossing point prediction algorithm of short-circuit current for mine-used phase-controlled switching was proposed. In the algorithm, DC component of short-circuit current is calculated by summing short-circuit current sampling data in one fundamental wave period after occurrence of three-phase short-circuit fault, which can reduce calculation amount and eliminate harmonic interference. AC component of short-circuit current is obtained by subtracting the DC component from the sampling data. Using periodicity of the AC component, the AC component at any sampling time after one fundamental wave period can be predicted. By adding the DC and AC components at any sampling time after one fundamental wave period, short-circuit current at any sampling time can be reconstructed to predict zero-crossing point of short-circuit current. The simulation and experimental results verify accuracy of the algorithm.