Description
⚙️ Product Specifications (Datasheet)
| Parameter | Value |
| Part Number | 9907-171 (505 / 505LST Series) |
| Device Type | Microprocessor-Based Digital Control for Large Reheat Steam Turbines |
| Input Power Supply | High Voltage AC/DC (180–264 VAC, 47–63 Hz or 200–300 VDC) |
| Enclosure Dimensions | 14.0″ W x 11.0″ H x 4.5″ D (356 mm x 279 mm x 114 mm) |
| Weight | Approx. 9.7 lbs (4.4 kg) |
| Country of Origin | USA (Woodward, Inc.) |
| Front Operator Panel | Integrated 2-Line x 24-Character Backlit LCD with 30-Key Keypad |
| Enclosure Protection | NEMA 4X / IP56 Rated Front Panel (Dust & Water Jet Resistant) |
| Communication Ports | Dual Serial Ports (RS-232, RS-422, RS-485 Modbus RTU) |
| I/O Configuration | Dual Speed Inputs, Dual Actuator Outputs (HP & Reheat Valves), 6 Analog I/O, 16 Digital Inputs |
🚀 Standard Operating Procedure
- Pre-Start System Inspection: Verify high-voltage power supply integrity, ensure MPT/proximity speed sensors are calibrated, and check field relay/trip circuit continuity.
- Power-On Diagnostics: Turn on the main breaker. Observe the Operator Control Panel (OCP) display as it runs internal processor self-checks and memory validation sequences.
- Control Mode Selection: Set control authority to Local OCP or Remote (DCS/SCADA) using front panel selection keys.
- Initiate Warm-Up Routine: Press the RUN/START key. The controller executes configured speed ramp rates, critical speed avoidance bands, and warm-up holds for high-pressure (HP) and intermediate-pressure (IP/Reheat) valve control.
- Reheat & Speed Monitoring: Continuously monitor turbine speed (RPM), main steam pressure, reheat bowl pressure, and valve position setpoints via the front display.
- Generator Synchronization: Ramp up turbine speed to rated conditions and close the generator main circuit breaker when synchronizing parameters are matched.
- Safe Shutdown Sequence: Press STOP on the front panel to initiate controlled ramp-down to idle speed before closing main steam stop valves completely.
⚙️ Parameter Configuration Guide
- Press the PRGM key on the OCP keypad to transition from Operation mode to Program mode.
- Enter the security passcode (Level 1/2) using the numeric keypad and press ENTER to confirm.
- Scroll through configuration blocks including Reheat Steam Logic, Speed Ramps, Valve Positioning Curves, and Overspeed Trip Setpoints.
- Select the target parameter, key in the new numerical value or toggle operational parameters, and confirm with ENTER.
- Save settings to non-volatile EEPROM memory prior to exiting configuration mode to retain parameters across power cycles.
🔄 Manual / Automatic Mode Switching
- To Select Manual Mode: Press the MANUAL button on the front panel interface. The manual LED illuminates, allowing plant technicians to directly command valve limiters, speed setpoints, and start/stop functions locally.
- To Select Auto Mode: Press the AUTO button on the panel. The AUTO LED illuminates, enabling internal automatic PID governing loops or external Modbus RS-485 / 4–20 mA remote signals from the DCS.
❓ Frequently Asked Questions (Q&A)
- Q: How does the 9907-171 handle large reheat steam turbine applications?
A: Model 9907-171 features specialized control algorithms designed to manage both High-Pressure (HP) inlet valves and Intermediate-Pressure (IP) reheat intercept valves simultaneously, maintaining system stability during sudden generator load rejections.
- Q: What power supply specification does model 9907-171 require?
A: Model 9907-171 utilizes a High-Voltage power input option, capable of operating continuous supply ranges of 180–264 VAC or 200–300 VDC.
- Q: Can this controller communicate directly with plant SCADA/DCS systems?
A: Yes, it includes dual serial communication ports supporting Modbus RTU (RS-232/RS-422/RS-485) protocols for full remote parameter tracking and control.
