Convertible Static Compensator Performance Studies on the NY State Transmission System

The New York Power Authority is installing a new flexible ac transmission system (FACTS) controller, known as the convertible static compensator (CSC), at the Marcy 345 kV substation. Two 100 MVA converters are installed. Through one 200 MVA shunt and two 100 MVA series transformers the converters may be connected to each other and to the system in 11 different configurations. This arrangement of the converters allows STATCOM, SSSC, UPFC, or IPFC deployment at the bus and two of the lines exiting the substation, namely, Marcy-Coopers Comers and Marcy-New Scotland 345 kV lines. Voltage, small signal, and transient stability simulations are conducted using the developed models of these configurations within the user-defined capability of EPRI´s power system analysis package. The focus of the studies is on finding out which configuration of the CSC provides the highest performance improvement from all stability points of view. Modulation controls are designed to improve inter-area oscillation damping. In general, all CSC configurations improve voltage, small signal, and transient stability margins of the system. The performance of the individual devices resulting from CSC configurations and their capabilities in the studied cases is presented. It is shown that the CSC in conjunction with three fixed capacitor banks at three other substations can increase the system power transfer limit by up to 31OMW.