To raise the technical level of professional technological personnel significantly and improve the operation level of power network

malfunction diagnosis and elimination of the 220 kV disconnecting switch are introduced

which happened in the Wulü transformer substation.The control fault phenomenon was briefly described.According to the circuit diagram

the cause was analyzed in detail and solved successfully

the reliability and security of power supply has been ensured.Through the analysis and research of the control fault

the corresponding operating experience was summarized to improve the capability and efficiency of operation and maintenance personnel when dealing with similar fault.The improvement scheme was put forward to enhance signal-sampling capability and fault diagnostic function of micro-computer protection device.The improvement strategies were presented to ensure the quality of power supply and help decrease the cost of the electric power production.