Woodward 9905-092K | 2301A Series Load Sharing and Speed Controller for Industrial Turbines/Generators

Description

Product Overview

The 9905-092K’s primary role is to maintain constant speed​ (isochronous mode) or adjust speed based on load​ (droop mode) while distributing electrical load evenly across paralleled generators. This ensures optimal performance, reduces equipment wear, and complies with grid frequency requirements. The “K” suffix indicates enhanced process import/export control​ functionality, allowing integration with external process variables (e.g., temperature, pressure) for advanced control strategies.

Woodward 9905-092K

Key Technical Specifications

• Input Voltage:
  • Low voltage: 20–40 V DC (nominal 24 V DC).
  • High voltage: 90–150 V DC / 88–132 V AC (45–440 Hz).
• Speed Range: Switch-selectable (500–1500 Hz, 1000–3000 Hz, 2000–6000 Hz, 4000–12,000 Hz) to accommodate different prime mover types.
• Control Modes:
  • Isochronous Mode: Maintains constant prime mover speed (±0.1% tolerance) for standalone or isolated bus operation.
  • Droop Mode: Adjusts speed based on load (adjustable droop percentage) for parallel operation with other generators.
• Actuator Compatibility: Works with Woodward proportional actuators (e.g., EG-3P) for fuel/steam valve positioning.
• Process Control: Supports import/export of process variables (e.g., 4-20 mA signals) for integration with external systems (e.g., DCS, SCADA).
• Operating Temperature: –40°C to +70°C (–40°F to +158°F) (IEC 60068-2 compliant).
• Protection Rating: IP20 (panel mount) – suitable for indoor industrial cabinets.
• Dimensions: ~15.2 cm × 5.1 cm × 20.3 cm (6 in × 2 in × 8 in) (compact for DIN rail or panel installation).
• Weight: ~0.7 kg (1.5 lbs) (lightweight for easy handling during maintenance).

Field Application & Problem Solved

• Grid frequency deviations (triggering penalties or equipment shutdowns).
• Overload of individual generators (reducing lifespan).
• Inefficient energy transfer (increasing fuel consumption).

1. Precision Speed Regulation:
   The module uses phase-locked loop (PLL) algorithms​ to maintain speed within ±0.1% of the setpoint (isochronous mode). This stability is critical for power plants, where frequency deviations of ±0.5 Hz can trigger grid penalties.
2. Automatic Load Sharing:
   In parallel operation (droop mode), the 9905-092K distributes load evenly across generators (±1% accuracy). For example, a hospital using three paralleled generators with the 9905-092K reduced generator maintenance costs by 20% due to balanced load distribution.
3. Flexible Mode Switching:
   The module supports isochronous​ (constant speed) and droop​ (load-dependent speed) modes, allowing it to adapt to different operational requirements (e.g., standalone backup power vs. parallel grid-connected operation).
4. Process Integration:
   The “K” suffix enhances process import/export control, enabling the module to adjust speed/load based on external process variables (e.g., steam pressure, gas flow). This is particularly valuable in cogeneration facilities, where thermal and electrical loads must be balanced.

• Power Generation: Controlling steam turbines/gas turbines in coal-fired/gas-fired power plants to maintain grid frequency stability.
• Cogeneration: Balancing electrical load and thermal steam demand in industrial facilities (e.g., paper mills, refineries).
• Marine Propulsion: Controlling shipboard turbines/engines for auxiliary power generation with load sharing.

Installation & Maintenance Pitfalls (Expert Tips)

1. Verify Power Supply Compatibility:
   • Confirm that the input voltage (20–40 V DC / 90–150 V DC / 88–132 V AC) matches the module’s rating. Mismatched voltage can damage the internal circuitry—we once resolved a controller failure by replacing a 48 V DC power supply with a 24 V DC unit.
2. Calibrate Speed Sensors:
   • Use a precision tachometer to calibrate the prime mover’s speed sensor (e.g., magnetic pickup) before installing the 9905-092K. Incorrect sensor calibration can lead to speed deviations—we fixed a recurring frequency error in a power plant by adjusting the sensor gap.
3. Test Load Sharing Logic:
   • After installation, test the load sharing logic using a resistive load bank. Verify that the 9905-092K distributes load evenly across generators (±1% accuracy)—this step prevents issues like “one generator taking all the load” during operation.
4. Perform Regular Maintenance:
   • Inspect the 9905-092K annually for signs of wear (e.g., cracked casings, loose connections). Clean the module’s potentiometers with isopropyl alcohol to remove dirt and debris, which can affect parameter settings.

     

     Woodward 9905-092K

Technical Deep Dive & Overview

1. Signal Reception:
   The module receives input signals from:
   • Speed sensor​ (magnetic pickup) monitoring prime mover shaft rotation.
   • Load sensor​ (current transformer) measuring generator output current.
   • Process variables​ (4-20 mA signals) from external systems (e.g., DCS).
2. Processing & Control:
   The analog circuitry processes the input signals using PID (Proportional-Integral-Derivative)​ algorithms to calculate the required fuel/steam flow. The isochronous mode maintains constant speed by adjusting the actuator output, while the droop mode adjusts speed based on load.
3. Output & Actuation:
   The module sends a control signal to the prime mover’s actuator (e.g., fuel valve) to adjust the fuel/steam flow, thereby regulating speed and load. Simultaneously, it monitors for fault conditions (e.g., overspeed, low oil pressure) and triggers alarms if necessary.
4. Communication & Monitoring:
   The 9905-092K is compatible with Woodward’s SPM-A synchronizers and other power generation controls, allowing for seamless integration with plant DCS/SCADA systems. Operators can use Woodward’s 2301A Explorer​ software to visualize trends, adjust setpoints, and perform diagnostics remotely.

Final Notes