The IS200STURH2A is a Simplex Primary Turbine Protection Input Terminal Board designed by General Electric (GE) for its gas and steam turbine control systems. This board is the complete version within the STUR series for generator drive systems, integrating synchronizing hardware and trip relays. It provides a comprehensive protection solution for generator drive systems requiring overspeed protection and primary synchronization functions.
The IS200STURH2A, as a simplex S-type version of the TTUR (Turbine Protection Input Terminal Board), works in conjunction with the PTUR I/O pack. It provides turbine-specific primary trip protection, speed signal input, and synchronization functions. The board features a DC-62 pin connector for mounting a single PTUR I/O pack, which communicates with the Mark VIe controller via Ethernet.
Key features of the IS200STURH2A include:
Complete Generator Protection: Integrates overspeed protection and primary synchronization functions, suitable for generator drive systems.
Onboard Trip Relays: Provides two trip solenoid outputs, K1 and K2, each consisting of a safety relay with forcibly guided contacts.
Synchronization Support: Provides two PT inputs for generator voltage and bus voltage signals, supporting synchronized closing of the main breaker 52G.
Four Speed Inputs: Accepts passive or active speed sensors, supporting speed detection as low as 2 RPM.
Rich Feedback Signals: Provides relay position feedback, solenoid voltage feedback, and sync circuit voltage feedback.
Pluggable Terminal Block: 48-terminal Euro-style pluggable terminal block for easy on-site wiring and maintenance.
Compatibility: Works with the PTUR I/O pack and requires ControlST software suite version 3.01 or higher.
Jumperless Design: The board has no configurable jumpers; all functions are fixed, simplifying field maintenance.
The board shares the same physical dimensions as other S-type terminal boards and can be stacked vertically. There are no components higher than the attached PTUR I/O pack, permitting double stacking of terminal boards.
II. Main Functions
The primary functions of the IS200STURH2A include, but are not limited to, the following:
1. Speed Signal Input
IS200STURH2A provides four speed input circuits that accept passive speed sensors or active speed sensors:
Passive Sensors: The signal is applied between terminals PR#_H and PR#_L (# is 1-4). The PTUR I/O pack can sense speeds as low as 2 RPM.
Active Sensors: The signal is applied between terminals TTL# and PR#_L.
2. Trip Relay Outputs
IS200STURH2A provides two trip solenoid outputs, K1 and K2, each consisting of a safety relay with forcibly guided contacts. Relay position feedback is provided to PTUR using one of the contact pairs in the relay. Extra customer terminals are provided to allow connecting two or three STUR boards in a redundant tripping configuration.
K1/K2 Relay Characteristics:
Each relay provides two normally open contacts and one normally closed contact.
Forcibly guided contacts ensure the feedback contact accurately represents the power contact position.
Supports TMR two-out-of-three voting configuration (requires three STUR boards).
3. Primary Synchronizing Function
IS200STURH2A, used with PTUR, supports synchronized closure of the 52G primary breaker. Key functions include:
PT Inputs: Terminals 21-24 provide generator voltage and bus voltage inputs.
Breaker Power: Terminal 27 (PGEN) accepts 24, 48, or 125 V dc positive power; terminal 32 (NGEN) accepts the power return.
Synchronizing Relays: The permissive relay K25P and synchronizing pilot relay K25 control breaker closing.
Backup Sync Check: An auxiliary backup sync check relay can be connected between terminals 29 and 30.
4. Feedback Signals
IS200STURH2A provides comprehensive feedback signals for system diagnostics and status monitoring:
Relay Position Feedback: Position feedback from K1 and K2 trip relays.
Solenoid Voltage Feedback: Solenoid voltage feedback associated with K1 and K2.
Sync Circuit Voltage Feedback: Five voltage feedback signals related to the sync function:
BKRVLT: Voltage status of the power bus used to close the breaker.
L52G: Voltage feedback from an auxiliary contact on the 52G breaker.
BKRPRM: Voltage status of the breaker close permissive relay contact, K25P.
BKRGES: Voltage status of the combination of K25P contacts wired in series with K25 contacts.
BKRGXS: Voltage status of the series combination of K25P, K25, and an auxiliary backup sync check relay (K25A), which equals the voltage applied to the breaker coil or a pilot relay.
Sync Relay Coil Drive Feedback: Two sync relay coil drive feedback signals.
5. Failure Detection
IS200STURH2A implements various fault detection functions via PTUR:
Speed inputs achieve failure detection through redundant signals applied to STUR.
PT inputs require external test signals for proper feedback.
Trip relays use forcibly guided contacts, ensuring feedback contacts accurately represent power contact positions.
Breaker closure relay contact logic includes voltage-based status feedback, announcing any unexpected behavior.
III. System Applications
1. Application in Generator Drive Systems
IS200STURH2A is a complete protection terminal board designed specifically for generator drive systems, suitable for applications requiring both overspeed protection and primary synchronization. Working with the PTUR I/O pack, it forms a complete turbine protection subsystem.
In a generator drive system, IS200STURH2A plays the following roles:
Overspeed Protection: Monitors turbine speed via speed inputs and triggers trip relays when speed exceeds setpoints.
Synchronized Closing: Monitors generator voltage and bus voltage via PT inputs to control synchronizing relays for closing breaker 52G.
Status Feedback: Provides comprehensive feedback to the control system on relay status, solenoid voltage, and sync circuit conditions.
2. Differences from Other STUR Versions
The STUR series has four main versions, with differences as follows:
| Version | Generator Application | Trip Connection | Application Scenario |
| IS200STURH1A | No | Onboard Trip Relays | Mechanical drive turbines (overspeed protection only) |
| IS200STURH2A | Yes | Onboard Trip Relays | Generator drive turbines (overspeed + sync) |
| IS200STURH3A | No | DC-37 pin connector to external trip board | Pulse inputs only, protection provided by external trip board |
| IS200STURH4A | Yes | DC-37 pin connector to external trip board | Generator drive, protection provided by external trip board |
3. Simplex System Application
In simplex applications, IS200STURH2A works with a single PTUR I/O pack to form a self-contained overspeed protection and synchronization function. The system can accept up to four speed signals to measure turbine speed, uses PT signals for automatic synchronization, and provides trip outputs via onboard trip relays.
4. TMR System Application
In applications requiring triple modular redundancy (TMR), three IS200STURH2A/PTUR combinations can be used. Each IS200STURH2A's trip relays provide two sets of normally open contacts, allowing external wiring to achieve two-out-of-three voting configuration. The board provides parallel customer terminals at critical points, allowing TMR relay contact voting wiring to be installed without violating the "one wire per terminal" principle.
IV. Detailed Interface Description
1. Customer Terminal Assignment Table
| Terminal | Signal Name | Description |
| 1 | K1_NO1_In | Relay K1 Normally Open contact #1 input (paralleled with terminal 2) |
| 2 | K1_NO1_In | Relay K1 Normally Open contact #1 input |
| 3 | K1_Centertap | Relay K1 Common |
| 4 | K1_NC_Out | Relay K1 Normally Closed contact output |
| 5 | K1_NO2_In | Relay K1 Normally Open contact #2 input |
| 6 | K1_NO2_Out | Relay K1 Normally Open contact #2 return (paralleled with terminal 7) |
| 7 | K1_NO2_Out | Relay K1 Normally Open contact #2 return |
| 8 | K2_NO1_In | Relay K2 Normally Open contact #1 input (paralleled with terminal 9) |
| 9 | K2_NO1_In | Relay K2 Normally Open contact #1 input |
| 10 | K2_Centertap | Relay K2 Common |
| 11 | K2_NC_Out | Relay K2 Normally Closed contact output |
| 12 | K2_NO2_In | Relay K2 Normally Open contact #2 input |
| 13 | K2_NO2_Out | Relay K2 Normally Open contact #2 return (paralleled with terminal 14) |
| 14 | K2_NO2_Out | Relay K2 Normally Open contact #2 return |
| 15 | SOL1_In | Solenoid 1 voltage sensor + input |
| 16 | SOL1_Ret | Solenoid 1 voltage sensor - input |
| 17 | SOL2_In | Solenoid 2 voltage sensor + input |
| 18 | SOL2_Ret | Solenoid 2 voltage sensor - input |
| 19-20 | - | Not Connected |
| 21 | GENH | Generator PT input high |
| 22 | GENL | Generator PT input low |
| 23 | BUSH | Bus PT input high |
| 24 | BUSL | Bus PT input low |
| 25 | B52GH | Output (PGEN) to B52G feedback contact |
| 26 | B52GL | Return side of B52G feedback contact |
| 27 | PGEN | Positive breaker coil power input |
| 28 | AUTO | Output of K25P contact closure |
| 29 | MAN | Output of K25 contact closure |
| 30 | BKRH | 52G Breaker Coil positive output |
| 31 | BKRH | Parallel connection to terminal 30 |
| 32 | NGEN | Negative breaker coil power connection |
| 33-36 | - | Not Connected |
| 37 | TTL1 | Active speed pickup input 1 |
| 38 | PR1_H | Passive speed pickup input 1 high |
| 39 | PR1_L | Speed pickup 1 return (active and passive) |
| 40 | TTL2 | Active speed pickup input 2 |
| 41 | PR2_H | Passive speed pickup input 2 high |
| 42 | PR2_L | Speed pickup 2 return (active and passive) |
| 43 | TTL3 | Active speed pickup input 3 |
| 44 | PR3_H | Passive speed pickup input 3 high |
| 45 | PR3_L | Speed pickup 3 return (active and passive) |
| 46 | TTL4 | Active speed pickup input 4 |
| 47 | PR4_H | Passive speed pickup input 4 high |
| 48 | PR4_L | Speed pickup 4 return (active and passive) |
2. Synchronizing Circuit Operating Principle
The synchronizing circuit of IS200STURH2A operates as follows:
Breaker positive power (24, 48, or 125 V dc) is applied to terminal 27 (PGEN), with the return connected to terminal 32 (NGEN). The presence of this voltage is indicated by the BKRVLT signal.
Positive power passes through the permissive relay K25P to terminal 28 (AUTO), with power status indicated by the BKRPRM signal.
Power then passes through the synchronizing pilot relay K25 to terminal 29 (MAN), with power status indicated by the BKRGES signal.
If a backup sync-check relay is used, it is wired between terminals 29 and 30 (BKRH), with closure indicated by the BKRGXS signal.
If a backup sync-check is not used, a jumper between terminals 29 and 30 completes the circuit, and both BKRGXS and BKRGES indicate that power is applied to the breaker coil.
The breaker coil or a pilot relay is wired between terminals 31 (BKRH) and 32 (NGEN).
V. Diagnostics and Configuration
1. Diagnostic Functions
IS200STURH2A performs the following diagnostic tests via the PTUR I/O pack:
| Diagnostic Item | Description |
| Solenoid Relay Driver Feedback | Checks solenoid relay driver signals; a fault is created if there is a problem with the control signal. |
| Relay Contact Position Feedback | Checks relay contact position feedback; a fault is created if there is a problem with the control signal. |
| Loss of Solenoid Power | Detects loss of solenoid power, creating a fault. |
| Synchronizing Relay Performance | Detects slow sync check relay, slow auto synch relay, slow breaker, and locked up K25 relay; all create a fault. |
| Composite Diagnostic Alarm | If any of the above signals goes unhealthy, a composite diagnostic alarm L3DIAG_PTUR occurs. |
| ID Chip Verification | Checks connector ID match; a mismatch creates a hardware incompatibility fault. |
Diagnostic signals can be individually latched and reset with the RESET_DIA signal after returning to normal.
2. Configuration Method
The IS200STURH2A board has no jumpers or hardware settings. All configuration is done via the PTUR I/O pack and ControlST software.
VI. Installation and Maintenance
1. Mounting Location
The IS200STURH2A board is mounted on a sheet metal carrier with a plastic insulator mount, then secured in the cabinet with screws. The board can be stacked vertically with other S-type terminal boards.
2. Installation Steps
Install the plastic insulator mount on the sheet metal carrier.
Mount the IS200STURH2A board onto the carrier.
Secure the assembly in the cabinet with screws.
Connect field wires to the pluggable terminal block.
Insert the PTUR I/O pack into the board's DC-62 pin connector.
Connect trip relay outputs, synchronizing circuits, and speed sensors as required.
3. 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 STURH2A board to reduce downtime in case of failure.
