Investigations of a thyristor-controlled series capacitor

Thyristor-controlled series capacitors (TCSC) are expected to provide many benefits for electric power systems including the increase of power transfer capability and transient stability as well as the mitigation of subsynchronous resonance (SSR). However, there has been little operating experience and thus further understanding of the characteristics of TCSC is still sought. A laboratory-scale TCSC has been designed, produced and installed on a laboratory power system at Kyoto University to investigate the performances of TCSC experimentally. The paper provides the fundamental impedance characteristics and the dynamic responses of the laboratory-scale TCSC, the effects of inductor and resistor size on these performances and a detailed analysis of loop current dynamics based on a developed mathematical model.