IS200TREGS4B - Gas Turbine Emergency Trip Terminal Board

SPECIFICATIONS:

Part Number: IS200TREGS4B
Manufacturer: General Electric
Series: Mark VIe
Product Type: Gas Turbine Emergency Trip Terminal Board
Number of trip solenoids: 3
Common Mode Voltage Range: ±5 V
Size: 17.8 cm wide x 33.02 cm
Operating temperature: 0 to 60 °C
MPU Pulse Rate Range 2 Hz to 20 kHz
Repair: 3-7 Days
Availability: In Stock
Country of Origin: United States
Manual: GEH6421L

FUNCTIONAL DESCRIPTION:

IS200TREGS4B is a Gas Turbine Emergency Trip Terminal Board manufactured and designed by General Electric as part of the Mark VIe Series used in GE distributed Gas Turbine Control Systems. The Gas Turbine Emergency Trip (TREG) terminal board provides power to three emergency trip solenoids and is controlled by the I/O controller. Up to three trip solenoids can be connected between the TREG and TRPG terminal boards. TREG provides the positive side of the DC power to the solenoids, and TRPG provides the negative side. The I/O controller provides emergency overspeed protection, emergency stop functions, and controls the 12 relays on TREG, nine of which form three groups of three to vote inputs controlling the three trip solenoids. There are several board types as follows:

• The H1A version is not used for new production and is replaced by H1B.
• H1B is the primary version for 125 V dc applications. Control power from the JX1, JY1, and JZ1 connectors is combined to create redundant power on the board for status feedback circuits and powering the economizing relays. Power separation is maintained for the trip relay circuits.
• H2B is used for 24 V dc applications. All other features are the same as H1B.
• H3B is a special version of H1B for use in systems with redundant TREG boards. The feedback circuit and economizing relay power are provided only by the JX1 connector.
• H4B is a special version of H1B for use in systems with redundant TREG boards. The feedback circuit and economizing relay power are provided only by the JY1 connector.
• H5B is a special version of H1B for use in systems with redundant TREG boards. The feedback circuit and economizing relay power are provided only by the JZ1 connector.

In redundant TREG applications, it is typical to find one H3B and one H4B board used together. System repairs must be done with the correct board type to maintain the control power separation designed into these systems. In Mark VIe systems, TREG is controlled by the PPRO pack on SPRO. The PPRO I/O packs plug into the D-type connectors on SPRO. Cables with molded plugs connect TREG to the SPRO board.

OPERATION:

TREG is entirely controlled by the VPRO protection module, and the only connections to the control modules are the J2 power cable and through the trip solenoids. In simplex systems, a third cable carries a trip signal from J1 to the TSVO terminal board, providing a servo valve clamp function upon turbine trip. Both TRPG and TREG control the trip solenoids so that either one can remove the power and actuate the hydraulics to close the steam or fuel valves. The nine trip relay coils on TREG are supplied with 28 V dc from the I/O controller. The trip solenoids are supplied with 125 V dc through plug J2 and draw up to 1 A with a 0.1-second L/R time constant.

SOLENOID TRIP TESTS:

Application software in the controller is used to initiate tests of the trip solenoids. Online tests allow each of the trip solenoids to be manually tripped one at a time, either through the PTR relays from the controller or through the ETR relays from the protection module. A contact from each solenoid circuit is wired back as a contact input to give a positive indication that the solenoid has tripped. Primary and emergency offline overspeed tests are provided too for verification of actual trips due to software-simulated trip overspeed conditions.

Two series contacts from each emergency trip relay (ETR1, 2, 3) are connected to the positive 125 V de feeder for each solenoid, and two series contacts from each primary trip relay (PTR1,2,3 in TRPG) are connected to the negative 125 V dc feeder for each solenoid. An economizing relay (KE1, 2, 3) is supplied for each solenoid with a normally closed contact in parallel with the current-limiting resistor. These relays are used to reduce the current load after the solenoids are energized. The ETR and KE relay coils are powered from a 28 V dc source from the I/O controller. Each PPRO I/O pack in each of the R8, S8, and T8 sections supplies an independent 28 V dc source.

The 28 V dc bus is current-limited and used for power to an external manual emergency trip contact, shown as E-STOP. Three master trip relays (K4X, K4Y, K4Z) disconnect the 28 V dc bus from the ETR and KE relay coils if a manual emergency trip occurs. Any trip that originates in either the protection module (such as EOS) or the TREG (such as a manual trip) will cause each of the three protection module sections to transmit a trip command over the IONet to the control module, and may be used to identify the source of the trip.

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FREQUENTLY ASKED QUESTIONS:

What is the exact role of the TREG board in the trip circuit?

The TREG board supplies the positive 125 V DC feeder to the emergency trip solenoids and contains the trip relays (ETR1–ETR3) used for voting logic. The corresponding TRPG board supplies the negative feeder and houses the primary trip relays (PTR1–PTR3). Both boards must operate together to complete the trip circuit and ensure redundancy.

How does the voting logic work for the trip solenoids?

Each trip solenoid is controlled by three ETR relays arranged in a 2-out-of-3 voting scheme. This means at least two relays must close to energize a solenoid, reducing the risk of false trips due to a single relay fault. The voting relays are powered by 28 V DC from independent I/O pack sources (R8, S8, T8) for redundancy.

What is the purpose of the economizing relays (KE1–KE3)?

Economizing relays are used to reduce the current load after initial solenoid activation. Each solenoid circuit includes a normally closed contact in parallel with a current-limiting resistor. Once the solenoid is energized, the economizing relay closes to bypass the resistor, reducing steady-state current draw and preventing overheating.

How is the control power separated in redundant TREG systems?

In redundant TREG applications, the control power is separated by using specific board versions (H3B, H4B, H5B) that receive feedback and economize relay power from only one connector (JX1, JY1, or JZ1). This prevents cross-powering and maintains isolation between redundant boards. Typically, one H3B and one H4B board are paired to ensure full redundancy.