Generator–Liquid Cooled Stator Skid Instrumentation/Runback Upgrades: Case Study

In many cases after 25 plus years of service it may be time to look at the replacement/ upgrade of the instrumentation associated with the stator water cooling skid applicable to armature bars that need to operate in a high or low oxygenated environment. Standards, codes, consolidation, location, redundancy, obsolescence, environmental, safety concerns and runback functionality should be reviewed prior to the next outage or scheduled stator rewind and prudent instrumentation enhancements, if deficient from the list above, should be considered. At the time of instrumentation upgrades, consideration should be given to relocation and improvement of the runback system, e.g. timers, relays, power supplies, and system functionality. Field adjustments quantifying the runback circuit is operating correctly, from both the series of on-off pulses to the turbine reference motor causing a proper load reduction rate and the two trip timers activating at the time the runback begins, need to be verified for proper operation.