Synchronous generator capability curve testing and evaluation

In the late 1980s, a variation in system characteristics in the Upper Ohio Valley resulted in changes in system performance. When the changes in system performance varied to a sufficient extent, the utilities in the upper Ohio Valley decided to perform a voltage coordination study. One facet of this study consisted of conducting MVAr capability range tests on all the synchronous generators comprising the Ohio Edison System. This study produced some interesting results relating to the validity of the synchronous generator capability curves supplied by the manufacturers as well as operating practices in the plants themselves. Operating the synchronous generators within limited MVAr ranges masked other problems which were not discovered until the synchronous generator MVAr capability range tests were performed