Disclosed is a method for identifying
transformer sympathetic
inrush current based on intelligent substation territory information. The method includes the following steps: (1) judging whether a
transformer is in a no-load shutdown state, (2) judging whether the phenomenon of no-load
transformer switching-in exists, (3) acquiring
line current of the switching-in side of the transformer which is switched in without load, acquiring
line current of primary and secondary sides of other operating transformers, and calculating differential current of the primary and secondary sides of the operating transformers, (4) continuously calculating the secondary
harmonic component of the operating transformers and carrying out timing from the moment of no-load switching-in till the secondary
harmonic component is larger than m% and fundamental
waves exceed by n% of rated current, (5) comparing the secondary
harmonic phase of the switched-in transformer and the secondary
harmonic phase of operating transformers, and (6) increasing the constant value of
differential protection starting current of the operating transformers to k1 times of an original starting value and carrying out timing, and setting the constant value to be the original starting value and returning the process to the step (1) when one of three conditions is met. According to the method for identifying the transformer sympathetic
inrush current based on the intelligent substation territory information, during the sympathetic
inrush current, protection can still be effectively carried out when internal fault of the transformers occurs; after the sympathetic inrush current,
differential protection action characteristics can return to original action states quickly.