Primary oil and secondary oil in the turbine control system
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The compressor in the device is driven by a turbine. There are terms such as primary oil and secondary oil in the turbine control system; what do they specifically refer to?
The primary oil is used to control the oil pressure (pump outlet pressure, quick-shut oil pressure), while the oil pressure generated by the electro-hydraulic converter in the secondary system is typically between 150–450 KPa
The oil for one cycle refers to the oil that activates the emergency shut-off valve, which is generated by creating control oil； Secondary oil refers to another stream of oil that acts on the speed control valve when adjusting the rotation speed. It is oil that receives speed signals through a speed sensor, is converted by an electro-hydraulic converter, and is then used to drive the throttle and the hydraulic actuator in order to open or close the speed control valve.
Simply put, the primary oil pressure is the oil pressure at the outlet of the oil pump, or the operating oil pressure after it has been adjusted by a throttle orifice plate; the secondary oil pressure serves as the power source for the high and medium control valves in the shutdown system once the control oil is established.
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The primary oil is connected to the hydraulic actuator and is used to drive the piston inside the actuator up and down, thereby controlling the opening degree of the control valve. The secondary oil acts on the bottom of the spool in the throttle valve, and it is used to control the flow of primary oil into the hydraulic actuator. The secondary oil primarily relies on the CCC control system to sense parameters such as the speed and pressure of the unit, and uses this information for feedback purposes.
Reply to 7# wm1208: Additional information – After coming out of the speed shutdown solenoid valve, the power oil enters the electro-hydraulic converter. There, it senses the speed of the turbine as well as the pressures in the main steam pipeline, exhaust pipeline, etc. The control system converts this information into an electrical signal, which is then transformed into an oil signal (i.e., secondary oil) by the electro-hydraulic converter. This oil signal acts on the bottom of the throttle slide valve, thereby controlling the path of the hydraulic motor (i.e., the primary oil path), with the aim of regulating the opening degree of the control valve.