The Turbine Electro Hydraulic Governor (EHG) Control System controls steam flow to the turbine thorough a series of servo-driven electro-hydraulic valves. The Mitsubishi Turbine EHG Control System can be applied to a variety of turbine generator system designs.
Mitsubishi provides a full lineup of field devices such as servo motors, Linear Variable Differential Transformers (LVDT), and magnetic speed pick-ups (tachometers) to support turbine-generation operation. The Mitsubishi Turbine EHG Control System is implemented with a digital nuclear instrumentation and Control (I&C) platform MELTAC.
The Mitsubishi Turbine EHG Control System is based on the MELTAC platform and its specialized I/O modules which have been developed to interface with the EHG-specific sensors and actuators. These specialized I/O modules ensure the response time required for turbine protection.
- Speed channel module: Detect the turbine speed and electrical over speed
- Servo driver module: drive the servo valves attached to the main steam valve actuators
- Over speed protection control (OPC) module: initiate the excitation of the OPC solenoid valves immediately when the turbine speed or load unbalance exceeds a pre determined set point value.
The Mitsubishi Turbine EHG Control System greatly improves turbine system reliability and significantly reduces turbine related down-time.
- The Mitsubishi Turbine EHG Control System can implement various automating functions such as valve test automation, free governor mode operation, and automatic turbine startup/shutdown. These functions reduce operator workload and reduce the risk of plant trips caused by human error.
- To ensure the response time necessary for reliable turbine control, dedicated, function specific I/O modules are provided for important features of the turbine-control system. These include servo-valve drivers, over speed protection, and tachometer distribution and processing modules.
- Redundancy is applied to the critical components in the system to prevents plant trips and output fluctuations that would be otherwise caused by single failures.
Feed Water Pump Turbine EHG Control System
Mitsubishi also provides a Feed Water Pump Turbine (FWPT) EHG Control System. The Mitsubishi FWPT EHG Control System is implemented with MELTAC to realize high reliability and maintainability.