Dynamic performance studies for a ±150 MVAr STATCOM for northeast utilities

Northeast utilities (NU), located in Hartford, Connecticut, is preparing to install a new flexible AC transmission system (FACTS) voltage sourced controller at its Glenbrook 115 kV substation in Stamford, Connecticut. Glenbrook is located within the Norwalk-Stamford area of southwestern Connecticut. In the summer of 2000, a low voltage event occurred in the area. Voltage recovery took approximately 8 to 10 seconds. Transmission planning studies have confirmed that the Norwalk-Stamford area is susceptible to a possible voltage collapse during certain contingencies. To mitigate similar low voltage conditions, NU decided to install a FACTS device at Glenbrook 115 kV substation. The reasons for this choice are given. The function of the STATCOM and its location on the system are discussed. The design of the STATCOM is described. The dynamic performance studies are described and some results of the studies are shown. The results demonstrate the effectiveness of the STATCOM in assisting the system voltage to recover following a fault.