Power Flow and Transient Stability Enhancement using Thyristor Controlled Series Compensation

TL (Transmission Line) congestion is a key factor that affects the power system operational cost. In addition of renewable generation in National Grid of Pakistan, transmission line congestion are frequent. Consequently, the network in this particular region faces severe congestion and dynamic stability problems. It has been planned that renewable plants shaved to curtail some available generation to minimize this inevitable congestion. However, one of the cost-efficient solutions to this problem is series compensation of lines using TCSC (Thyristor Controlled Series Compensation). It significantly increases the transfer capability of existing power transmission and enhances the dynamic stability of system at a lower cost, and has shorter installation time as compared to the construction of new TLs. This paper deals with the dynamic modeling of a TCSC in the NTDC (National Transmission and Dispatch Company) network with its applications to alleviate congestion during fault conditions. This study has been carried out using simulation software PSS/E (Power System Simulator for Engineers) which does not have a predefined dynamic model for TCSC, this leads to the necessity of creating a user defined model. The model of TCSC has been programmed in FORTRAN and compiled along with existing dynamic models of network components. The results indicate that power flow and dynamic stability of network is enhanced.