An approach to standing phase angle reduction

This paper is part of a series presented on behalf of the System Restoration Subcommittee with the intent of focusing industry attention on power system restoration. The presence of excessive standing phase angle (SPA) differences across open circuit breakers causes significant delays in power system restoration. These angles may occur across a tie line between two systems or between two connected subsystems within a system. They must be within SPA limits before an attempt is made to close breakers to firm up the bulk power transmission system. There has been a need for an efficient methodology to serve as a guideline for reducing excessive SPA differences to allowable limits, without resorting to the raising and lowering of various generation levels on a trial and error basis. This paper describes such a methodology