Description
The Woodward 9907-135 is a GS3/LQ driver module manufactured by Woodward, classified as a fuel valve actuator driver module. It provides direct electrical execution of liquid and gaseous fuel modulation commands within Woodward GS3/LQ valve control systems.
The Woodward 9907-135 converts 4-20 mA demand signals into regulated output currents for GS3, LQ3, LQ25, LQ25T, and LQ bypass series liquid fuel valves, while processing single speed feedback resolver signals for closed-loop actuator control. It is designed for use in gas turbine, steam turbine, and compressor drive applications where precise fuel metering is essential for speed regulation and load control .
Application Scenarios
In a combined-cycle power plant operating GE LM6000 gas turbines, the fuel control system must modulate liquid fuel flow with millisecond-level precision to maintain stable combustion during load changes and grid frequency events. A failure in the fuel valve driver can trigger turbine trip, causing generation loss and potential grid instability.
The plant selected the Woodward 9907-135 as the fuel valve driver within its GS3/LQ control architecture. The module receives a 4-20 mA demand signal from the turbine control system and converts it into a controlled current output that positions the LQ25 liquid fuel valve. Simultaneously, the Woodward 9907-135 processes resolver feedback from the valve actuator to verify that the commanded position has been achieved, closing the loop on fuel metering accuracy .
During a grid frequency dip event, the turbine control system commanded a rapid increase in fuel flow. The Woodward 9907-135 responded within its specified latency window, driving the LQ25 valve to the new position while continuously monitoring resolver feedback for position agreement. The turbine maintained combustion stability through the transient, and the plant avoided a trip event that would have cost an estimated $150,000 in replacement power purchases. The Woodward 9907-135’s dual feedback processing capability allowed the control system to distinguish between a valve positioning delay and an actual actuator fault, preventing an unnecessary protective shutdown .
