An efficient faults calculation method taking into account mutually coupled lines of power systems

It is necessary to take into account the effects of mutual couplings when unbalanced faults are to be calculated in transient stability study. When the method based on symmetrical coordinates is applied to faults calculation, it has been necessary in the conventional method to construct the zero sequence network, the configuration of which is more complex than other networks so far. Then, the application of faults calculation including mutual couplings to the analysis on the bulk power system model has been considerably difficult for a long time. This report presents a newly developed method to calculate the effects of mutual coupling in multifaults calculation under the same configuration and with no change for all sequence networks. The validity of the proposed method was verified through the application of transient stability analysis for power system models.