AN INVESTIGATION OF AIR BAFFLE FAILURES AND VIBRATION CHARACTERISTICS OF MOTOR-GENERATORS AT THE BATH COUNTY PUMPED STORAGE STATION - PART I: A CASE STUDY

摘要

The Bath County Pumped Storage Station, the largest of its type in the world, consists of six 350 MWe reversible pump-turbine/motor-generator units. Virginia Power became aware of vibration related problems at the Station during operation of the units following commissioning of the plant in December, 1985. A regular problem was cracking of the support angles and loss of fasteners from the cooling air baffle system. The loss of bolts also caused significant damage to two of the units. There have been other vibration related problems, such as the loss of wicket gate linkage bolts and loosening of stator hold down bolts. An extensive in-service experimental study was initiated from January, 1987, to determine the root cause of the problem and to arrive at a permanent solution, while the units continued to operate with several temporary precautionary measures such as frequent inspections, replacement of support angles and tack welding of fasteners of supporting structures for the baffles. The details of the testing program form a separate part of this paper. The study identified the problem areas and suitable modifications were designed to eliminate the problem. The modifications are being implemented.