Influence of the Steinmetz Circuit Capacitor Failure on the Electric System Harmonic Response

Traction systems are generally single-phase loads that can cause voltage unbalances which affect the electric system operation. It is usual to delta-connect reactances with these single-phase loads to reduce voltage unbalances. The set of reactances and single-phase loads is known as a Steinmetz circuit. A parallel resonance can be produced between the capacitive reactance of the Steinmetz circuit and the system inductive reactances, which can damage power quality. This paper locates the frequency of this parallel resonance analytically and studies the influence of capacitor loss with respect to its design value. Experimental measurements are also presented to validate the obtained analytical results