Operational experience of Tucson Electric Power´s SVC

During the spring of 2008, Tucson Electric Power (TEP) and ABB successfully commissioned a Static Var Compensator (SVC) at a 138 kV substation located in central Tucson, Arizona. During system events, the SVC provides dynamic support that includes the ability of switching four mechanically switched capacitors (MSCs). The SVC also reacts to diurnal voltage changes and switches the MSCs for steady state voltage support to maintain adequate dynamic VAr margin. The following paper examines the configuration and topology of the 138 kV substation as well as the control strategy to ensure optimal reactive power compensation while still maintaining reactive reserves and SVC availability. Specific system events and switching instances are further discussed.