IEEE Transactions on Power Systems, Vol. 13, No. 1, February 1998 zyxwvu 145 zy Application of an Energy Source Power System Stabilizer on the 10 MW Battery Energy Storage System at Chino Substaition Bharat Bhargava Gary Dishaw Southern California Edison Co. by zyxwvu Abstract zyxwvutsrqpo Southern California Edison (SCE) installed a 10 MW Battery Energy Storage System (BESS) at its Chino substation facility in 1988. The BESS facility has been in operation for the last six years and has been used for load leveling andpeaking functions. The BESS power conversion system was built with the then state of the art technology and has a very fast response rate when changing power output of the batteries. SCE recently installed an Energy Source Power System Stabilizer (ESPSS) to test the concept of providing damping of power system swings using the ESPSS. The ESPSS basically modulates the power output zyxwvu / input of the energy storage batteries to respond to system frequency deviations caused by power system oscillations, The ESPSS differs @om a conventional Power System Stabilizer. It is designed to change the power output ofthe power source rather than the voltage or the reactive power output. While installing the ESPSS several upgrades to the BESS were made to improve reliability. Installation of the ESPSS on the battery enables SCE to test the concept zyxwvuts of system stabilization using power source output modulation instead of reactive power modulation. The energy storage batteries provide an easy test bed for conducting field tests and response ofthe ESPSS to system disturbances. This paper discusses the BESS, the ESPSS and presents recently recorded results@om system disturbance monitoring and field tests conducted on the ESPSS and the batteries. zyxwvutsr PE-411-FWRS-O-03-1997 A paper recommended and approved by the IEEE Power System Engineering Committee of the IEEE Power Engineering Society for publication in the IEEE Transadions on Power Systems. Manuscript submitted July 30 1996; made available for printing March zyxwvutsrqpon 26. 1997. Introduction SCE Co. is a large, United States investor owned electrical utility with over 18,000 MW peak load. The company serves an approximately 50,000 square mile area of Southern California in the USA with more than four million customers. The company imports up to 40 YO of its power from the Northwestern United States and from Arizona utilities in the Southwestern United States. These transmission paths are fairly long, and are generally heavily loaded. The transmission of power on these paths is limited by transient and dynamic instability at high levels of power imports in addition to the thermal limitations on some transmission lines. The transmission paths zyx are also, at times, heavily loaded because of unscheduled power flow or loop flow on these paths. This limits SCE's capability to import power. SCE is part of a big O-ring (donut) transmission system of the Western States Coordinating Council (WSCC) which is comprised of 14 Western U.S. states, British Columbia (Canada) and part of Northwestern Mexico. Operating experience and extensive studies conducted on this WSCC system have shown that unstable system oscillations can occur between the Northwest and Southwest at about 0.3[1,2] Hz and between California and Arizona at about 0.7 Hz at high levels of imports or when system generationis low. These system oscillations limit the power transfers on the two power transmission access paths to SCE. SCE installed a 10 MW, 40 MWH BESS at it's Chino 230169112.5 kV substation in 1988. This is the largest battery storage facility in the world. The BESS has been used for load leveling, black start capability and reducing system losses by reducing the power flow during the peak hours for the last eight years. SCE procured an ESPSS system from GE and installed it on the Chino BESS in December, 1994. SCE developed specificationsfor special filtering bandwidth that would allow the ESPSS to respond to frequency deviations in the range of 0.3-0.7 Hz. Based on these specifications GE modified their existing PSS system to meet our needs. SCE conducted field tests and monitoring the effective performance of the ESP'SS in regulating the power output of the batteries to provide damping to the 0.3 and 0.7 Hz power system oscillation modes. 0885-8950/98/$10.00 0 1997 IEEE