The closing resistor of circuit breaker can effectively suppress the closing inrush current and switching over-voltage and play an important role in stable operation of power grid. The closing resistor will

once in case of fault and of correct operation and out of operation

causing huge equipment and safety accidents. Since the 1 100 kV GIS circuit breaker is of mostly multi-break structure

the coordination time sequence deviation across open contacts and the interference of contact bounce factor often lead to the characteristics of the closing resistor with no way to be measured

or the error of the test result is too large. As for such event that the pre-switching time and the resistance of the closing resistor of 1 100 kV GIS circuit breaker has no way to be detected

its structure and test principle are analyzed. It is concluded

through increasing the test frequency to obtain the complete test waveform

that one of the reasons that the pre-switching time and its resistance of the closing resistor have no way to be measured is the failure of across open contacts of closing resistor at one side. It is found through disassembly and inspection that the moving contact at one side of the closing resistor peels off due to breakage of the fixing bolt

and the conclusion that the operation characteristic has no way to be detected due to failure of open contacts of the resistor is verified. Finally

the corresponding suggestions and improvement measures are proposed from such aspects as manufacturing process

test items

test instruments and detection means

which can provide reference for process control and fault diagnosis of the same type of equipment.