Woodward 9905-377 | DSLC Digital Synchronizer and Load Control Module for Industrial Power Systems

Description

Product Overview

Key Technical Specifications

• Input Voltage: 85–265 V AC (50/60 Hz) – supports both European (230 V AC) and North American (120 V AC) power standards.
• Control Modes:
  • Automatic Synchronization: Matches generator frequency (±0.1 Hz tolerance) and phase (±5 electrical degrees tolerance) to the online system.
  • Load Control: Supports droop​ (load-dependent speed adjustment), baseload​ (fixed load output), and isochronous​ (constant speed) modes for flexible operation.
• Protection Features: Built-in reverse power relay to prevent back-feeding into the grid, ensuring safety during parallel operation.
• Communication Interfaces: RS-232, Ethernet – supports Modbus RTU protocol for integration with plant DCS/SCADA systems.
• Operating Temperature: -40°C to +70°C (-40°F to +158°F) – suitable for extreme industrial environments (e.g., power plants, marine vessels).
• Dimensions: Compact form factor (typical: ~280 mm × 210 mm × 90 mm) – fits standard industrial cabinets.
• Weight: ~3.0 kg (6.6 lbs) – lightweight for easy handling during maintenance.

  

  WOODWARD 9905-377

Field Application & Problem Solved

• Electrical faults (e.g., short circuits, equipment damage).
• Grid penalties (e.g., fines for frequency deviations).
• Downtime (e.g., generator tripping, process interruptions).

1. Precision Synchronization:
   It uses phase-locked loop (PLL) algorithms​ to match the offline generator’s frequency and phase with the online system within tight tolerances (±0.1 Hz, ±5 electrical degrees), ensuring compliance with grid requirements and preventing phase mismatch faults.
2. Automatic Load Sharing:
   In parallel operation (droop mode), the 9905-377 distributes load evenly across generators (±2% accuracy), reducing equipment wear and optimizing energy transfer efficiency.
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).

• Power Generation: Synchronizing standby generators to the utility grid during peak demand or outages.
• Marine Propulsion: Synchronizing shipboard generators for auxiliary power generation with load sharing.
• Industrial Facilities: Balancing electrical load in cogeneration plants (combined heat and power) or industrial parks with multiple generator sets.

Installation & Maintenance Pitfalls (Expert Tips)

1. Verify Power Supply Compatibility:
   • Confirm that the input voltage (85–265 V AC) matches the module’s rating. Mismatched voltage can damage the internal circuitry—use a multimeter to check the input voltage before installation.
2. Calibrate Speed Sensors:
   • Use a precision tachometer to calibrate the prime mover’s speed sensor (e.g., magnetic pickup) before installing the 9905-377. Incorrect sensor calibration can lead to synchronization errors—verify with a multimeter.
3. Test Synchronization Logic:
   • After installation, test the synchronization logic using a signal generator to simulate frequency/phase changes. Verify that the module correctly adjusts the generator’s speed and sends a synchronization signal when the conditions are met.
4. Perform Regular Maintenance:
   • Inspect the 9905-377 annually for signs of wear (e.g., cracked casings, loose connections). Clean the module’s connectors with isopropyl alcohol to remove dirt and debris, which can cause communication failures.

     

     WOODWARD 9905-377

Technical Deep Dive & Overview

1. Frequency Measurement: The module measures the online system’s frequency using a phase-locked loop (PLL) circuit.
2. Speed Adjustment: It sends a control signal to the generator’s actuator (e.g., fuel valve) to adjust the generator’s speed until it matches the online system’s frequency.
3. Phase Matching: Once the frequency is matched, the module aligns the generator’s phase with the online system’s phase using a phase comparator.
4. Load Distribution: In parallel operation, the module uses droop control​ to adjust the generator’s speed based on load, ensuring even distribution across units.

Final Notes