Overspeed trip testing of steam turbines
Overspeed trip testing of steam turbines
(OP)
Hello,
I have seen various vendor OEM recommendations on performing the plant overspeed trip testing on steam turbines. I recollect reading in a paper where the vendor was recommending using a bypass on the steam line for some reason to do a proper over speed test. I cannot excatly recollect the stated reason for the bypass but I am inclined to believe that this would be for a controlled injection of the steam in to the turbine while doing the trip test.
I suppose this would be in addition to using the governing system to control speed and steam injection. What advantages would such a bypass on the inlet steam line provide from overspeed trip testing stand point. The only reason I could see it to not solely rely on the governing valve incase it is stuck or malfunctions.
Any and all input would be highly appreciated.
Much thanks
I have seen various vendor OEM recommendations on performing the plant overspeed trip testing on steam turbines. I recollect reading in a paper where the vendor was recommending using a bypass on the steam line for some reason to do a proper over speed test. I cannot excatly recollect the stated reason for the bypass but I am inclined to believe that this would be for a controlled injection of the steam in to the turbine while doing the trip test.
I suppose this would be in addition to using the governing system to control speed and steam injection. What advantages would such a bypass on the inlet steam line provide from overspeed trip testing stand point. The only reason I could see it to not solely rely on the governing valve incase it is stuck or malfunctions.
Any and all input would be highly appreciated.
Much thanks
RE: Overspeed trip testing of steam turbines
"If you want to acquire a knowledge or skill, read a book and practice the skill".
RE: Overspeed trip testing of steam turbines
If the turbine uses a hydraulic / mechanical governor or an electronic governor with an override, this would be used to control the turbine speed up to over-speed. If the turbine governor does not have an override (often the case on smaller turbines), then the governor valve can be blocked open and the small bypass valve can be used to control the turbine speed up to over-speed for the testing. We often do this on smaller, single stage turbines that use hydraulic governors that do not have an installed override mechanism.
Johnny Pellin