Which expert has the schematic diagram of its structure?
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Recently, during operation, it was found that the electro-hydraulic converter of the turbine (I’m not sure if this is the correct term; that’s how I call it) does not have sufficient pressure for rapid shutdown. The problem lies in this component. I’m not familiar with its internal mechanism, so I dare not attempt to fix it on my own. I would appreciate advice from the experienced users on this forum; anyone who has previously repaired or disassembled this component would be especially helpful!
First, determine the cause of the low pressure: 1. Is it due to a decrease in pressure at the pump outlet? 2. Is there a problem with the quick-shut oil pressure gauge? 3. Another possibility is that there is an issue with the quick-shut assembly. If oil is leaking from the quick-shut oil pipeline back into the return oil pipeline, then it will be necessary to disassemble it for inspection. 4. Is the quick-shut oil supply pipeline unobstructed? These are the only points that come to mind!
My opinion is to first check all the factors in the oil pipeline that could affect oil pressure, such as the pressure reducing valve and the manual valves used to regulate oil pressure. Examine the pressure trends of high-pressure and low-pressure oils, as well as the temperature of the lubricating oil. Only after ruling out all these possibilities should we consider the issues related to the quick-shut off control device. There are many diagrams of such devices available on forums; the original poster can search for them
For Hangqi, the drawings can be found here
A few days ago, our company’s turbines also encountered the same problem, with the same type of quick-shut valve assembly. After completing the static tests, the quick shut-off valve was opened, the control valve was set to an opening degree of around 8, and the turbine operated normally in simulation mode. Then, the emergency stop button on the 505 control panel was pressed to shut down the system; after that, the oil pressure dropped below 0.75, triggering a cascade alarm from 505. Oil pump output: 0.6; control oil: 0.6; before the regulating valves of the main oil inlet pipes for each bearing: 0.6; quick-shut oil: 0. Upon further investigation, it was found that the DCS had not been reset; after resetting, the pressure was 0.9, while it should be 1 under normal conditions. Further inspection revealed that the needle valve in the return line of the regulating oil dual-filter system was fully open. After closing that valve, the pressure of the regulating oil became 1, while that of the quick-shut oil became 0.5. During a static test, the pressure of the quick-shut oil was 0.9, and the quick-shut valve operated properly with normal regulation. Is it the low shut-off oil pressure at normal operating speed, or is it the inability to establish the shut-off oil pressure after the start-up oil has been established, or is it the low shut-off oil pressure before restarting the machine after an emergency stop? Check each case separately; the reasons vary for different situations. At present, what is the oil pressure in the main oil regulator pipe at the oil pump outlet? Check the return valve to see if it is open, and verify whether the emergency shut-off valve has been activated. Also, inspect the speed control valve switch of the oil pump – the two-position four-way valve marked as the speed control valve – to ensure that the valve core is not stuck and that there are no leaks due to improper sealing
What are the pressure and quick-shut oil pressure after adjusting the oil filter, and what is the pump outlet pressure at the moment? Is the oil pressure low right after performing certain operations during operation?
What is observed is that it is a steam extraction condensing turbine; the high-pressure inlet shut-off valve is functioning properly, but the low-pressure steam extraction shut-off valve will not open
First, check whether the interlocks related to the process and ESD have been reset, and then see if there are any operations that do not meet the requirements when establishing the starting oil pressure.
This is called a quick-shut combination device, for Hangzhou Motor’s engines. You can take apart the external manual directional valve, shutdown solenoid valve, etc. to clean them; in particular, the valve spool inside must be removed, cleaned, blown dry with compressed air, and then reinstalled.