Abstract
The static VAR compensators having fixed capacitor thyristor controlled reactor (FC-TCR) used to improve voltage stability in power systems are nonlinear elements. The fixed capacitor group will produce reactive power while the thyristor controlled reactor will consume reactive power in compensators having FC-TCR. Changing the firing angles of TCR provides the reactive power variation of the system since the reactive power production of capacitors is fixed at a determined voltage level. In some cases, the variation of these firing angles will cause the harmonics in the system. In this study, TCR's are discussed to be harmonic sources and the resonance case caused by harmonics has been investigated with Fourier Matrix Model and MATLAB Software.