Abstract: This article starts from the higher requirements of economic and social development for the reliability of substation power supply. Without the function of high-voltage side switch failure tripping, once the 220 kV bus fails, it will lead to the inability to timely cut off the power supply point isolation fault and expand the fault range to affect the 110 kV system. It seriously affects the reliability of power supply. Thus, it is further pointed out how substations can further improve the failure and tripping function on the basis of traditional equipment, ensuring the reliable operation of the power grid.