The IS200TPROH1B is an Emergency Protection Terminal Board designed by General Electric (GE) for its gas turbine control systems. This board is an important hardware revision within the TPRO series, primarily used to provide speed signals, temperature signals, generator voltage, and bus voltage to the VPRO processor board as part of an independent emergency overspeed and synchronization protection system.
The IS200TPROH1B board works in conjunction with triple-redundant VPRO boards to form a protection module independent of the main turbine control system. This protection system controls the trip solenoids via TREx (TREG, TREL, or TRES) terminal boards, implementing emergency shutdown protection for the turbine. TPRO provides input signals to all three VPRO boards, ensuring that protection functions can still be performed normally even if one channel fails.
The main functions of the IS200TPROH1B board include:
Emergency Overspeed Protection: Provides speed signals to VPRO via magnetic speed pickups, implementing emergency overspeed protection independent of the main controller.
Backup Sync Check Protection: Provides backup protection for synchronization closing via generator voltage and bus voltage inputs.
Exhaust Overtemperature Protection: Monitors gas turbine exhaust temperature via thermocouple inputs, providing overtemperature protection.
Analog Inputs: Provides three analog current/voltage input channels for monitoring other process parameters.
The board designs the demands of industrial field applications, featuring pluggable terminal blocks for easy on-site wiring and maintenance. Each termination point can accept up to two #12 AWG wires with 300-volt insulation. The board dimensions are 17.8 cm wide × 33.02 cm high, suitable for standard control cabinet installation.
II. Main Functions
The primary functions of the IS200TPROH1B include, but are not limited to, the following:
1. Speed Signal Input and Overspeed Protection
The IS200TPROH1B board provides speed signals to VPRO for Emergency Overspeed (EOS) protection. Speed detection uses passive magnetic speed pickups, with the following specific configuration:
Total of 9 passive magnetic speed pickups can be connected.
Each VPRO board monitors 3 speed pickups.
Probe output signals are transmitted via shielded twisted pair cables, with a maximum distance of 300 meters (984 feet).
Pulse rate range: 2 Hz to 20 kHz.
Input circuit sensitivity: Minimum 27 mV peak at 2 Hz, minimum 450 mV peak at 14 kHz.
2. Backup Sync Check Protection
IS200TPROH1B provides backup sync check inputs to the protection module, including:
Generator voltage and bus voltage, sourced from two single-phase Potential Transformers (PTs).
Nominal input voltage: 115 V rms.
Allowable voltage range for synchronizing: 75 to 130 V rms.
Voltage accuracy: 0.5% of rated voltage.
Frequency accuracy: 0.05%.
Phase difference measurement: Better than 1 degree.
Load per input: Less than 3 VA.
Isolation rating: 1,500 V rms isolation barrier.
Maximum cable length: 100 meters (18 AWG shielded twisted pair).
Each PT input is internally connected in parallel through TPRO to the three VPRO boards. The triple-redundant phase slip windows result in a voted logical output on the TREG terminal board, which drives the K25A relay. This relay's contacts are connected in series with the synch permissive relay (K25P) and the auto synch relay (K25) to ensure that no false command is issued to close the generator breaker. Similarly, contacts from the K25A contact are connected in series with contacts from remote, manual synchronizing equipment to ensure no false commands.
3. Thermocouple Inputs
IS200TPROH1B provides 9 thermocouple input channels, primarily used for gas turbine exhaust overtemperature protection. Each VPRO board monitors 3 thermocouple inputs. The thermocouple specifications are the same as for the VTCC board.
4. Analog Inputs
IS200TPROH1B provides three analog input channels, with VPRO supplying 28 V dc power for the analog input transmitters:
Channel 1: Configurable via jumpers JP1A and JP1B for 4-20 mA current input or voltage input (±5 V dc or ±10 V dc).
Channel 2: 4-20 mA current input.
Channel 3: 4-20 mA current input.
The analog input specifications are the same as for the VAIC board.
5. Signal Distribution
All input signals (speed, voltage, thermocouple, analog) are connected in parallel through TPRO to the three VPRO boards, achieving triple redundancy. This design ensures that protection functions can still be performed normally even if one VPRO board fails.
III. System Applications
1. Application in Gas Turbine Protection System
The IS200TPROH1B is the core input terminal board of the independent emergency protection system for gas turbines. It works with triple-redundant VPRO processor boards to form a protection module independent of the main turbine control system. This system controls the trip solenoids via TREx and TRPx terminal boards to implement emergency shutdown protection.
2. Coordination with VPRO and TREx
In the protection system, the boards coordinate as follows:
IS200TPROH1B: Acquires speed, voltage, thermocouple, and analog input signals, distributing them in parallel to the three VPRO boards.
VPRO: Processes input signals, performs emergency overspeed protection and emergency stop functions, and controls the 12 relays on TREG.
TREG: Provides the positive side of 125 V dc to the trip solenoids, working with TRPx to control the solenoids.
TRPx (TRPG/TRPL/TRPS): Provides the negative side of 125 V dc to the trip solenoids.
Trip Solenoids: Up to 3 can be connected, independently tripped by VPRO via TREG or by the main controller via TRPx.
3. Relationship with Main Controller
The emergency protection module containing IS200TPROH1B is completely independent of the main turbine control system (VTUR). Both VTUR and VPRO detect turbine overspeed, and either system can independently trip the turbine using relays on TRPG or TREG. This redundant design ensures that even if the main control system fails, the emergency protection system can still function correctly.
4. Backup Sync Check Protection
The generator voltage and bus voltage inputs provided by IS200TPROH1B are used for backup sync check protection. The triple-redundant phase slip windows result in a voted logical output on TREG, driving the K25A relay. This relay's contacts are connected in series with K25P and K25 to ensure that no false closing commands are issued. Similarly, K25A's contacts are also connected in series with contacts from remote manual synchronizing equipment to prevent incorrect operation.
5. Exhaust Overtemperature Protection
For gas turbine applications, the 9 thermocouple inputs on IS200TPROH1B are primarily used for exhaust overtemperature protection. Each VPRO monitors 3 thermocouples, achieving triple-redundant temperature monitoring. When exhaust temperature exceeds the set threshold, the protection system can trigger an emergency shutdown.
6. Typical Application Scenarios
Emergency overspeed protection for gas turbines
Exhaust overtemperature protection for gas turbines
Backup sync check protection for generators
Safety shutdown systems independent of the main controller
Industrial turbomachinery requiring triple-redundant protection
IV. Detailed Interface Description
1. Terminal Block Allocation
The IS200TPROH1B board features two pluggable terminal blocks:
First Terminal Block: Connects generator potential transformers, bus potential transformers, analog inputs, and thermocouples.
Second Terminal Block: Connects magnetic speed pickups.
Each termination point can accept up to two #12 AWG wires with 300-volt insulation. The terminal blocks can be unplugged for easy on-site wiring and maintenance.
2. Signal Connections
The board connects to each VPRO board via two cables. Refer to the wiring diagram in the document for specific connection methods.
3. Jumper Configuration
| Jumper | Function | Setting Description |
| JP1A | Analog Channel 1 Type Selection | Works with JP1B to select 4-20 mA or voltage input |
| JP1B | Analog Channel 1 Type Selection | Works with JP1A to select 4-20 mA or voltage input |
4. ID Chip
The connectors on IS200TPROH1B feature a read-only ID chip storing the following information:
Board serial number
Board type (TPROH1B)
Revision number
Plug location
VPRO boards read this information during startup and compare it with expected values. If a mismatch is encountered, a hardware incompatibility fault is generated, preventing system problems caused by incorrect configuration.
V. Diagnostics and Configuration
1. Diagnostic Functions
VPRO boards perform the following diagnostics on TPRO, its cables, and input signals:
| Diagnostic Item | Description |
| Analog Input Limit Check | Performs high/low limit checks on analog input signals; exceeding limits generates a fault |
| Composite Diagnostic Alarm | When any signal goes unhealthy, generates L3DIAG_VPROR (or S/T) alarm |
| Fault Latching and Reset | Diagnostic signals can be individually latched and reset with RESET_DIA after returning to normal |
| ID Chip Verification | Checks connector ID match, prevents hardware incompatibility |
2. Configuration Method
Aside from the analog channel 1 type selection jumpers, the TPROH1B board has no other configurable hardware. All other configurations (such as limit settings, alarm thresholds, etc.) are completed via VPRO software.
VI. Installation and Maintenance
1. Mounting Location
The IS200TPROH1B board is typically mounted in the independent protection module within the gas turbine control cabinet. During installation, pay attention to:
Ensure the board is firmly mounted to avoid vibration effects.
Terminal blocks should be fully seated and screws tightened.
Cables should be correctly labeled to avoid misconnection.
Shields should be properly grounded.
2. Maintenance Recommendations
Periodic Inspection: Check that terminal blocks are securely plugged in and wires are not loose.
Cleaning: Regularly clean the board to prevent dust accumulation.
ESD Protection: Wear a grounding strap when handling the board and store it in anti-static bags.
Spare Parts Management: Maintain a spare IS200TPROH1B board to reduce downtime in case of failure.
