IS200TRESH1B is an Emergency Overspeed Protection Board developed by GE. It is a part of Mark VIe control system. The TRES is a component designed for the emergency overspeed protection of small to medium-sized steam turbines. This system plays a vital role in preventing turbine damage and ensuring operational safety by swiftly shutting down the turbine in case of overspeed conditions.
POWER AND CONTROL
TRES is controlled by an I/O controller, which oversees the operation and power supply to the system. The system provides power to three emergency trip solenoids, which are essential for initiating a rapid turbine shutdown when required. These solenoids are connected between the TRES and TRPS terminal boards. Specifically, TRES supplies the positive side of the 125 V DC power to the solenoids, while the TRPS terminal board supplies the negative side, completing the circuit necessary to activate the solenoids.
The I/O controller is responsible for several critical functions within the TRES system:
Emergency Overspeed Protection: The I/O controller monitors the turbineâs speed and, if it detects an overspeed condition, it triggers the emergency trip solenoids to shut down the turbine.
Emergency Stop Functions: In addition to overspeed protection, the I/O controller can initiate an emergency stop, ensuring the turbine is brought to a halt safely and quickly.
Relay Control: The I/O controller also controls three relays on the TRES board, each of which is linked to one of the three trip solenoids, enabling precise and reliable operation.
SYSTEM CONFIGURATION
Simplex and TMR Form: The TRES system is available in both Simplex and Triple Modular Redundancy (TMR) configurations. The TMR form provides enhanced reliability by using redundant components to safeguard against system failures.
Dry Contact Inputs: TRES includes seven dry contact inputs designed for trip interlocks. These inputs allow the system to interface with other protective devices and ensure that all necessary conditions are met before a trip is initiated.
No Economizing Relays: The TRES system does not include economizing relays. Economizing relays typically reduce the power consumption of the solenoids after they have been activated, but this feature is not present in the TRES design.
No Emergency Stop Inputs: The TRES board itself does not have dedicated emergency stop inputs. However, the emergency stop functionality is managed through the I/O controller, which integrates with the TRES system.
MONITORING AND RELAY DRIVERS
In the TRES system, the excitation and signal from the seven dry contact inputs are continuously monitored and fed to the I/O controller. This monitoring ensures that the system is aware of the status of all interlocks and can react accordingly to protect the turbine.
The board also includes two critical relay drivers:
Synch Check Relay Driver (K25A): This driver, along with its associated monitoring components, ensures that the turbine synchronization process is safely managed. The synch check relay prevents the turbine from connecting to the grid if synchronization conditions are not met, thereby protecting both the turbine and the grid.
Servo Clamp Relay Driver (K4CL): The servo clamp relay driver and its monitoring systems control the turbineâs servo mechanisms, which are essential for precise turbine operation and control.
