What are DCS, DEH, TSI, and ETS, and what is their relationship?

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What are DCS, DEH, TSI, and ETS, and what is their relationship? DEH is used to control the speed and load of the turbine, as well as pressure and other auxiliary parameters ； ETS is a shutdown protection system that ensures the safe and stable operation of the steam turbine; it enables the turbine to shut down safely in case of any abnormalities ； DCS is primarily used for controlling boilers, and it is employed for the control of various boiler and turbine equipment throughout the facility ； TSI is used for monitoring the important parameters during the operation of the steam turbine, and it can send a shutdown signal in case of abnormalities to ensure the safe stop of the turbine; these four elements are interconnected and work together. None of them can be missing. TSI system: Turbine monitoring and control instrument system; oil overspeed signal, lubricating oil pressure dropping by 0.02, activation of the generator’s main protection, etc.). When the corresponding interlocks are activated and a signal is received, power is supplied to the magnetic relief solenoid, thereby releasing the primary safety oil and additional backup oil to shut down the machine ； Additionally, the corresponding action signals are sent to the DCS system at the same time for recording and display. DEH system: A digital electro-hydraulic control system that primarily converts corresponding electrical signals into hydraulic signals in order to control the turbine. It can generate an AST action signal to directly activate the AST solenoid valve, thereby releasing high-pressure fire-resistant fuel and achieving shutdown. DCS: Distributed Control System, where all signals are gathered and sent to the system for display, recording, and other tasks. First of all, their hardware is different. It basically consists of 3 independent systems. TSI stands for turbine monitoring instrument, which is primarily used to measure parameters such as turbine shaft vibration, bearing vibration, eccentricity, speed, displacement, and thermal expansion. An alarm signal is generated whenever any of these measured values exceed the set limits; in addition, it provides signals for automatically activating the barring gear as well as for starting and stopping the top shaft oil pump. Signals such as displacement, vibration, and differential expansion are all involved in the main steam turbine trip protection. The collected signals also need to be transmitted to the DEH and ETS systems. ETS stands for Turbine Trip Protection System. When the turbine is operating abnormally and the turbogenerator control system is unable to keep the turbine system within normal parameters, ETS triggers a trip of the turbine in order to prevent damage to the turbogenerator system, by closing all of the turbine inlet valves. The specific protection functions vary from factory to factory. DEH stands for Digital Electronic Control System, whose main function is to control the speed of the turbine ； Automatic synchronization control ； Load control ； Participate in a frequency modulation session ； Coordinated control of machine and furnace ； Rapid load reduction ； Main steam pressure control ； Single-valve control, multi-valve decoupled control ； Valve testing ； Engine programmed start ； OPC control ； Control under load shedding and loss of magnetization conditions ； Dual-machine fault tolerance ； Achieve data sharing with the DCS system ； Manual control. The trip signal needs to be transmitted to the ETS to enable protection.