The rated short-time withstand (thermally stable) current of a high-voltage circuit breaker refers to the effective value of the current that the circuit breaker can withstand when the circuit breaker is in the closed position during the rated short-circuit duration under the specified use and performance conditions, that is, allowable The maximum current passed. The thermal stability current indicates the ability of the circuit breaker to withstand the thermal effect of the short-circuit current. When the thermally stable current passes through the circuit breaker, within the specified time, the temperature does not exceed the allowable heating temperature specified by the standard, and there is no contact welding or other phenomena that prevent it from continuing to work normally. Generally, the thermal stability current of a circuit breaker is equal to its rated short-circuit breaking current.