Effects of voltage-waveform distortion in TCR-type compensators

The effect of system voltage distortion on the performance of a thyristor controlled reactor (TCR) type of compensator is examined. Toward this end, the real and imaginary values of harmonic current through the TCR, and the optimal gating angle that controls it, are calculated with a view toward minimizing the RMS value of the supply current and to achieving an optimum power factor (PF). The precision of the formulae obtained, assuming an equal conduction angle of the thyristors in the two half periods, is compared with the results achieved using two different methods for simulating the TCR, one by means of a Pascal program and the other with PSPICE. The optimum PF values, calculated by analytical methods that use the conventional formulation (which assumes that the voltage waveform is sinusoidal), are compared with those obtained using the formulation developed here.