Determination of the Suitable Value of Resonance Point for Best Operation of Thyristor Controlled Series Capacitor

Electricity generation is experiencing a remarkable diversion in recent years, where some effects drive it to such that, for example, electricity demand due to increasing of using electrical and electronic appliances, Market forces where the large companies are competing to increase their shares in the electrical aspect, and also the shortage of the natural resources is one of the most effective aspects for this diversion. With a view to increasing the power system transfer capabilities, a Flexible Ac transmission system (FACTS) could be a solution with its different categories. One of the categories is called Thyristors controlled series capacitor (TCSC). The TCSC is attached to the network in series, where the overall effective transmission line impedance can be controlled in order to increase the transfer power capability.From the three different operation modes, a Vernier mode was chosen, and because of the thyristor theory of how current pass within the thyristor controlled reactor (TCR) branch, the RMS value of the TCR current can vary and leads the equivalent impedance of TCR to change its inductance value from the basic value to infinity.In this paper, choosing the suitable value for the resonance point in Vernier mode, which determines the range of inductive and capacitive region of the TCSC, was considered.To simulate that, the IEEE 14 bus test system was applied in the Neplan program. And the simulation results showed great advances in power transfer capabilities as well as bus voltages.