Comparison of modern STATCOM and synchronous condenser for power transmission systems

This paper presents a comparison between Synchronous Condenser and STATCOM as a dynamic source of reactive power. It focuses on the differences in the operating principles, steady-state and dynamic performance. Although both devices are able to provide capacitive and inductive current to the network, the dynamic behavior is principally different. The difference in the amount of the injected current as a response to network contingencies is explained by means of V/I diagrams. Another factor is the speed of the response. To consider it, the comparison is done for two time periods - transient (0.5-1sec.) and an emergency period (few seconds) after a contingency occurs. The paper addresses the recent growing interest in synchronous condenser application, due to its unique ability to contribute to the system inertia and short-circuit power. This paper also includes the comparison of losses, since it is a growing concern and an important selection criterion between Synchronous Condenser and STATCOM.