A Comparative Study of Ground Fault Analysis for a Practical Case of a Transmission Line Equipped with Different Series FACTS Devices

Due to the rising power demand and increasing population worldwide, electrical power networks have been extensively growing and striving to satisfy the escalating loads. This necessitates the need for using Flexible AC Transmission System (FACTS) devices which have become indispensable during normal and abnormal operating conditions. This paper investigates the impact of using series FACTS devices, namely Thyristor Controlled Series Capacitor (TCSC), GTO Controlled Series Capacitor (GCSC) and Thyristor Controlled Series Reactor (TCSR), on the impedance and power flow of a practical 400 kV transmission line in the Algerian power network. It also investigates the effect of varying the fault resistance on short-circuit calculations in the case of a phase to ground fault that occurs at the end of the compensated line. Analytical formulas of the employed FACTS devices, the system model under fault and short-circuit calculations are deduced and presented in the paper. Simulations results obtained using MATLAB are demonstrated for the compensated line and without compensation. These simulations are compared to show the effect of using these devices for the studied cases. It is concluded that GCSC provides better performance in the active and reactive power flow of the line under normal operating conditions and in reducing the fault current during abnormal operating conditions when the fault resistance increases. On the other hand, TCSR shows a better performance in maintaining higher voltages under fault with the increase of fault resistance.