Risk-based placement of TCSC for transient stability enhancement

TCSC is one of the most appropriate devices to improve the transient stability of power systems. Since in today's competitive environment, investments in power systems need to be cost-effective, in this study, a procedure is presented to determine whether using TCSC for transient stability improvement is cost-effective or not. To this purpose, the transient instability risk is estimated both with and without TCSC. Afterwards, a comparison is made between the amount of improvement made in transient instability risk and the investment cost of TCSC. In the proposed procedure, the probabilities of transient instability and its cost are used to estimate the transient instability risk. To calculate the transient instability probability, a conditional method is used. This method is applied on the IEEE 9-bus as well as New England test systems. The simulation results demonstrate that the proposed procedure is capable of determining the cost-benefit size and number of TCSC units. Furthermore, results indicate that in some cases, installing TCSC to only improve transient stability is devoid of monetary value.