History has repeatedly demonstrated the need to start generating units without access to the external power grid. This "Black Start" ability speeds power system recovery from both system instabilities and,natural disasters. Readiness for an actual Black Start condition can be demonstrated by bringing a generator up to speed and synchronizing it to the electric system without using any grid power for auxiliary functions. Salt River Project, based in Phoenix, Arizona, conducted an exercise using a number of hydroelectric generating stations and a thermal-generating station. This was a legitimate "Black Start" exercise because every part of the system connecting the hydro and thermal generation was fully isolated (islanded) from the Western Electric Coordinating Council (WECC) power grid. Synchronized phasor measurements, or synchrophasors, provided a real-time measurement of conditions during this Black Start exercise. Frequency and phase angles were monitored both within the island and on the WECC power grid. By using synchrophasor technology, frequency and phase angle in the two systems could be compared in real time without the use of a physical connection. This paper illustrates the use of synchrophasor data to view frequency stability, verify system independence, and observe the synchronization point. Phasor measurement units, together with synchrophasor collector and display software, provided valuable data to operators during the course of the exercise. This paper provides discussion of problems encountered, trade-offs made, and lessons learned during the exercise.
