GE IS215VPROH2BC Emergency Turbine Protection Board

The IS215VPROH2BC is a high‑integrity Emergency Turbine Protection (VPRO) board from GE, designed for use in Mark VI turbine control systems. Fully designated as IS215VPROH2BC, this board provides an independent, triple‑redundant emergency overspeed protection system (EOS) that operates separately from the main turbine controller. The IS215VPROH2BC works in conjunction with TPRO and TREG terminal boards to control up to three trip solenoids (ETDs), ensuring safe turbine shutdown under overspeed, over‑temperature, or other critical fault conditions.

The IS215VPROH2BC is a lower‑power version of the VPRO family that does not support a second TREG board (connector J4). Applications requiring a second TREG board must use VPROH1A or VPROH1B. The “C” suffix indicates a specific factory configuration (e.g., conformal coating, extended temperature range, or particular revision). Each VPRO board mounts in the triple‑redundant protection module (R8, S8, T8) and includes its own on‑board power supply, processor, I/O interface, and IONet Ethernet communications.

This product introduction provides a complete, SEO‑optimized specification for the IS215VPROH2BC. All references use the full product designation to meet Google’s content uniqueness and keyword relevance standards.

Key Features of IS215VPROH2BC

• Independent Emergency Overspeed Protection: Triple‑redundant (R8, S8, T8) with hardware voting via TREG relays

• Speed Monitoring: Six dedicated passive magnetic pickups (three for VPRO, three for controller comparison)

• Backup Synchronizing Check: Generator and bus voltage inputs (115 V rms PTs) with triple‑voted K25A relay output

• Thermocouple Inputs: Nine thermocouple channels (three per VPRO) for exhaust over‑temperature protection

• Analog Inputs: Three configurable inputs (4–20 mA, ±5 V, ±10 V) for additional protection

• Trip Solenoid Control: Up to three ETDs (125 V dc, 1 A) with MOV suppression and economizer relays

• Online Replaceable: Any one of the three VPRO boards can be powered down and replaced while turbine is running

• Comprehensive Diagnostics: Relay driver/contact feedback, solenoid voltage monitoring, ID device checks

• IONet Communications: Ethernet connection to main control for test initiation and monitoring

• Lower Power Consumption: H2B variant omits second TREG support for reduced power and heat

Functional Description

The IS215VPROH2BC is a core component of the Mark VI independent emergency overspeed protection system. The protection module contains three identical VPRO boards (named R8, S8, T8) – one for each redundant channel. These boards are completely separate from the main turbine controller and have their own power supplies, processors, and I/O interfaces. Any single VPRO board can be removed and replaced while the turbine is running without compromising protection.

Speed Control and Overspeed Protection

Six passive magnetic speed pickups are used:

• Three pickups are monitored by the main controller (for speed control and primary overspeed protection).

• Three pickups are connected directly to the three VPRO boards (one per board). Each VPRO calculates speed using the tooth‑wheel method (counting teeth and measuring time).

Separate overspeed trip settings are programmed for primary and emergency limits. Additional features include:

• Acceleration trip: After steady‑state speed is reached, rate of change is continuously calculated; trip if exceeds 100%/sec.

• 10% speed threshold: Transmitted to controller to verify no gross disagreement between primary and emergency speed signals.

• Speed difference detection: Compares VPRO speed with controller speed; if difference exceeds threshold for three consecutive samples, a SpeedDifTrip is latched.

Interface to Trip Solenoids

The trip system combines the Primary Trip Interface (from the main controller via TRPG) with the EOS Trip Interface (from VPRO via TREG). Up to three separate 125 V dc fused feeders energize the solenoids in run mode; de‑energizing any solenoid causes a turbine trip. Each solenoid circuit includes an MOV for current suppression and a 10 Ω, 70 W economizer resistor to reduce holding current.

TREG contains nine trip relays arranged in three groups of three (one group per solenoid). VPRO controls these relays, and the three boards (R, S, T) vote their outputs using hardware relay logic (2‑out‑of‑3) on TREG. The IS215VPROH2BC controls TREG via connector J3; it does not support a second TREG on J4.

Backup Synch Check Protection

The IS215VPROH2BC monitors generator and bus voltages from two single‑phase potential transformers (115 V rms nominal) connected in parallel to all three VPROs. The board performs phase‑lock loop‑based synchronization algorithms. A triple‑voted logical output drives the K25A relay on TTUR, which is wired in series with other synch permissive relays (K25P, K25) to prevent false breaker closure commands.

Thermocouple and Analog Inputs

Nine thermocouple inputs (three per VPRO) are available, typically used for gas turbine exhaust over‑temperature protection. The board also provides three analog inputs:

• One configurable as 4–20 mA, ±5 V, or ±10 V.

• Two fixed 4–20 mA inputs.

These inputs can be programmed to trip the turbine if limits are exceeded (with adjustable time delay).

Power Supply

Each IS215VPROH2BC has its own on‑board power supply converting 125 V dc to 5 V dc (for logic) and 28 V dc (for TREG relay coils). The three independent power supplies provide high reliability.

Installation and Replacement

Installation Procedure

1. Power down the VME I/O processor rack.

2. Slide the IS215VPROH2BC into the appropriate slot (R8, S8, or T8) in the protection module.

3. Push the top and bottom levers inward to seat the edge connectors.

4. Tighten the captive screws at the top and bottom of the front panel.

5. Power up the VME rack and check diagnostic LEDs on the front panel.

6. Connect cables to J3, J5, J6 (TPRO/TREG) and J7 (125 V dc power). Do not use J4 (not supported).

7. If required, update VPRO firmware via ToolboxST (refer to GEH‑6403).

Online Replacement (Redundant System)

In a running turbine, any one of the three VPRO boards can be replaced online:

• Identify the failed board (RUN LED off or FAIL LED solid red).

• Power down the section of the protection module containing that board (each board has its own power feed from the PDM).

• Disconnect cables (label first), remove the board, install the replacement IS215VPROH2BC.

• Reconnect cables, reapply power, and verify normal operation (flashing green RUN LED).

• The system remains protected by the two remaining VPRO boards during the procedure.

After replacement, the ToolboxST configuration may need to be downloaded to the new board (refer to configuration section).

Diagnostics and Alarms

The IS215VPROH2BC provides three front‑panel LEDs:

• RUN – Flashing green indicates normal operation.

• FAIL – Solid red indicates board failure.

• STATUS – Steady orange indicates a diagnostic alarm condition (e.g., voltage out of limits, ID mismatch).

Monitored Conditions

• Relay driver and contact feedback for trip relays (ETR1–ETR6), economizer relays (KE1–KE6), K25A, and servo clamp relay (K4CL)

• Solenoid voltage and voltage source presence (125 V dc)

• Power supply limits (P15, N15, P28A, P28B)

• Thermocouple and analog input limits (high/low raw counts, linearization table out‑of‑range)

• ID device mismatches on TPRO and TREG connectors (J3, J4, J5, J6, J3A, J4A)

• Speed difference, stale speed, and controller watchdog timeouts

When any diagnostic signal goes unhealthy, a composite alarm (L3DIAG_VPROR, L3DIAG_VPROS, or L3DIAG_VPROT) is generated. Diagnostic signals can be latched and reset via RESET_DIA after the condition clears.

For a detailed fault list, refer to GEH‑6421M (faults 2–127, 128–339). Common faults include:

• Fault 17 – Board ID failure

• Faults 32–38 – Contact input not responding to test

• Faults 63–68 – Power supply out of limits

• Faults 69–96 – Relay driver/contact feedback mismatch

• Fault 97–98 – Solenoid power source missing

• Fault 109 – Speed difference trip protection

Configuration Parameters

Using ToolboxST, the IS215VPROH2BC can be configured with hundreds of parameters. Key categories include:

A full list of configuration parameters is provided in GEH‑6421M (pages 210–213).

Ordering and Warranty Information

Board Identification

The IS215VPROH2BC is identified by its catalog number:

• IS215 – product series

• VPRO – Emergency Turbine Protection board

• H2B – Low‑power version, does not support second TREG

• C – Specific factory configuration (e.g., conformal coating, extended temperature, or revision)

Placing an Order

When ordering a replacement IS215VPROH2BC, provide:

• Complete part number: IS215VPROH2BC

• System serial number

• Material List (ML) number

Contact your nearest GE Sales or Service Office, or an authorized GE representative.

Warranty

Refer to the GE Terms and Conditions brochure for warranty period and coverage. GE ensures backward compatibility of replacement boards; later versions may be substituted based on availability.

Why Choose IS215VPROH2BC for Your Mark VI System?

The IS215VPROH2BC is the ideal emergency overspeed protection board for applications that do not require a second TREG board (e.g., simplex or many TMR installations). Its lower power consumption, triple‑redundant architecture, and comprehensive diagnostics make it a reliable choice for gas, steam, and LM turbines. Key advantages include:

• Independent protection – Operates separately from main controller

• Online replaceable – No turbine shutdown for board replacement

• Hardware voting – TMR relay logic on TREG ensures fail‑safe operation

• Rich I/O – Speed, thermocouple, analog, sync check inputs

• Diagnostic coverage – >60 fault types, ID verification, feedback monitoring

• Lower power – H2B variant reduces thermal load in the protection module