Guest
we have attended to the repair of all underwater parts on In-Situ basis of a 36MW hydro kaplan unit which were silt eroded. However, minor leakage occuring through the runner blade trunnions could not be stopped due to deep cavity formation in the runner hub. since the customer wants the unit to be run for the peak rainy season and plan for the renovation of the unit in Oct., 2001 we spun & loaded the unit successfully with all parameters including vibration normal.
However, we could not increase the load beyond 18-20MW on account of the fact that runner blades are not getting operated beyond a limit i.e. 5 degrees ( total blade span being from -7.5 to + 15 degrees). it may be noted that prior to the unit spinning, alpha-beta characteristics of the turbine were set and no such problem was encountered. in order to check the problem, unit was again taken under shutdown and alpha-beta relation was checked and blades were observed to move quite freely. it may not be out of place to mention that the oil leakage through the blades is very small as compared to the one existing before taking the unit for repairs when there was no problem with the blade operation in load.
kindly arrange to post your views on this problem.
(A.K.KOUL)
Dy. General Manager(HYDRO SERVICES)
BHEL, INDIA
However, we could not increase the load beyond 18-20MW on account of the fact that runner blades are not getting operated beyond a limit i.e. 5 degrees ( total blade span being from -7.5 to + 15 degrees). it may be noted that prior to the unit spinning, alpha-beta characteristics of the turbine were set and no such problem was encountered. in order to check the problem, unit was again taken under shutdown and alpha-beta relation was checked and blades were observed to move quite freely. it may not be out of place to mention that the oil leakage through the blades is very small as compared to the one existing before taking the unit for repairs when there was no problem with the blade operation in load.
kindly arrange to post your views on this problem.
(A.K.KOUL)
Dy. General Manager(HYDRO SERVICES)
BHEL, INDIA
