The rated voltage of a high-voltage circuit breaker refers to the upper limit of the highest voltage of the power system where the circuit breaker is located. In order to achieve consistency with the IEC standard, the my country Standards Committee proposed in 1994 to change the "highest voltage" used in the past to "rated voltage".

GB 311.1-1997 "Insulation coordination of high-voltage transmission and transformation equipment" refers to the system voltage as the nominal voltage, and changes the maximum system voltage to the rated voltage of the electrical equipment. At present, the standard value of rated voltage of electrical equipment in my country is:

Range I, the rated voltage is 252kV and below: 3.6, 7.2, 12, 24, 40.5, 72.5, 126 (123), 252 (245) kV.

Range II, rated voltage above 252kV: 363, 550, 800, 1100kV.

These have different definitions from the previously mentioned rated voltage.