Method for performing preventive test without detaching high-voltage lead of 220-kV zinc oxide arrestor

A method for performing preventive test without detaching high-voltage lead of 220-kV zinc oxide arrestor belongs to the measurement field. An upper segment lead of the zinc oxide arrestor is grounded; a direct current high voltage is added to the bottom of the upper segment zinc oxide arrestor through a high-voltage microammeter by a direct current generator; the high-voltage microammeter is connected with the upper segment zinc oxide arrestor through a shielding line; the bottom of a lower segment zinc oxide arrestor is disconnected from an online detector; the bottom of the lower segment zinc oxide arrestor is grounded through the microammeter; current reading I2 of the microammeter at low-voltage side is read to obtain a leak current value of the lower segment arrestor; the leak current value of the upper segment arrestor is obtained by using the current reading I of the microammeter at high-voltage side to subtract the current reading I2 of the microammeter at low-voltage side. The preventive test can be performed without detaching the high-voltage lead of the 220-kV zinc oxide arrestor, the method is simple to operate and can ensure test error with labour and material being saved; the maintenance interruption time is reduced and the test work efficiency is improved.