Calculation of electrical quantities for relay protection of multiphase power lines

Abstract

The paper analyzes the method of calculating the electrical quantities (currents and voltages) for relay protection for different short circuits and phase failure, which can take place on the multiphase electrical power lines. In the base of this method is used the resolution of unbalanced system of vectors (voltages and currents) of “m”-phase power transmission line into the “m”-systems of symmetrical components. This enables to simplify calculations, including simulation them on the computer and detecting short circuits and failures of the phases by relay protection of the multiphase electrical power lines.