Method for judging magnetizing inrush current of no-load transformer during switching phase reclosing process of circuit breaker

The invention discloses a method for judging the magnetizing inrush current of a no-load transformer during the switching phase reclosing process of a circuit breaker, which comprises the following steps: when over current is generated in a switching phase reclosing process of a circuit breaker, an equivalent circuit and a corresponding voltage equation are established based on the switching-on phase number and the switching-on phase current characteristic; calculating the equivalent inductance value of each sampling time according to the voltage and the current sampling values and taking theaverage value; comparing the average equivalent inductance value with a threshold value. When the average equivalent inductance value is greater than or equal to the threshold value, the condition ismagnetizing inrush current. When the average equivalent inductance value is smaller than the threshold value, the condition is short circuit failure. If the average equivalent inductance value is notonly one, when all of the a