The problem
In the early 1990s the Bradley Lake hydro generation project was taken into service. The project was built to reduce Alaska’s dependence on oil. The project included the upgrading of the existing 300 km power transmission system between the hydro station situated on the Kenai peninsula and the main load center around Anchorage. The transmission grid as it was built, could not safely handle the added generation from Bradley Lake without encountering stability problems.
The solution and alternative
Comparing upgrade alternatives FACTS was found superior. The addition of a second transmission circuit was also considered but was ruled out based primarily on economical reasons. An important factor was also that the FACTS option could be realized within a very short time frame.
Two ABB Static Var Compensators (SVC) were installed and they have been in operation since 1993 in the 115 kV kV transmission system. One SVC is located at Soldotna, (rated at 110 Mvar range), the other one at Daves Creek (rated at 35 Mvar range). The compensators offer dynamic voltage control as well as damping of active power oscillations which tend to build up between Bradley Lake and generating plants around Anchorage as well as Fairbanks further to the north, especially during heavy power export from the Kenai Peninsula. Both SVCs have an inductive as well as a capacitive output range, a fact that enables them also to provide overvoltage suppression at line switching and energization