WOODWARD 9907-028 SPM-A SYNCHRONIZER

The Woodward 9907-028 is a generator speed and phase synchronization control module of the Woodward SPM-A series, specifically designed for automatic parallel control of power system generators. This module can achieve precise frequency and phase alignment before the generator is connected to the grid or other generators in parallel, providing reliable synchronization conditions for subsequent circuit breaker closing, thereby enhancing the smoothness and safety of power system parallel switching.

 

                 

1. Automatic Frequency and Phase Matching Control
The core control function of 9907-028 SPM-A SYNCHRONIZER is to automatically detect and match the frequency and phase difference between the generator and the bus (or another generator). The module is equipped with a phase detection circuit and a filtering unit, which are used to extract precise signals from the respective voltage waveforms and compare the differences. When the frequency and phase difference fall within the set range, it can trigger further operations.
Phase matching accuracy: ±10° (module nominal value), used to ensure that the phase error before the gate is sufficiently small and coordinated.
Frequency consistency: It requires both power supplies to have extremely close frequencies, thereby reducing mechanical shocks and electromagnetic disturbances.
This function is equivalent to a phase-locked loop system, constantly adjusting the generator control signal to ensure that the output frequency is "locked" to the target frequency.
2. Output of closing control signal for circuit breaker
9907-028 SPM-A SYNCHRONIZER not only checks the synchronization conditions, but also issues a circuit breaker closing signal after achieving frequency/phase matching and the conditions have been met for a certain period of time. This output is usually a relay contact, which can directly drive the circuit breaker or serve as a logic input for PLC/DCS.
Closing signal duration: Approximately 1 second (typical value) to ensure that the control device can reliably capture the signal.
Contact type: Normally open relay contacts, suitable for driving various loads.
3. Optional matching time and dynamic response adjustment
The 9907-028 SPM-A SYNCHRONIZER enables the selection of the **time window for synchronous determination (match-up dwell time)** internally and the dynamic adjustment of parameters. This determines how long to maintain stability and trigger the closing event after the synchronous conditions are met. This is crucial for different generator inertia, load characteristics, and grid conditions.
The typical settings include various delay times, such as 1/8, 1/4, 1/2, and 1 second, which can be optimized according to the system's response speed.
4. Multiple working mode control
9907-028 SPM-A SYNCHRONIZER offers four operation modes, which can be switched by on-site switches, making the engineering debugging and operation control more flexible:
OFF - Module deactivated, not involved in the synchronization logic;
RUN - Normal synchronization and capable of generating a closing signal;
CHECK - The synchronization judgment and monitoring function is effective, but the closing command is not allowed.
PERMISSIVE - Enables synchronous logic but restricts its impact on the main engine control.
This mode control facilitates the decoupling of synchronous braking from the generator control strategy, thereby enhancing debugging and safety.
5. Compatibility of Output Impedance Selection and Control
To accommodate different types of main controllers, such as Woodward 2301/2301A, EPG electronic speed control system or 2500 series control units, 9907-028 SPM-A SYNCHRONIZER offers various output impedance types:
High impedance output - suitable for old-style electronic load sharing control such as 2301;
Low impedance output - Compatible with controllers such as 2301A, EPG/2500, etc.
Special output of EPG - This is the control architecture used for load-sharing among EPG controllers without any load.
Such output options ensure that the module can be seamlessly integrated with various control systems.

 

1.Specialized Design for Parallel System Optimization
9907-028 SPM-A SYNCHRONIZER is not a general measurement module. Instead, it is a synchronous control unit specifically designed for generator parallel operation conditions. Its internal logic is optimized around the dynamic transition process before paralleling, with a focus on enhancing the system stability and mechanical safety of the generator when it connects to the busbar.
2.Logical decoupling of synchronization determination and execution logic
9907-028 SPM-A SYNCHRONIZER separates the synchronization condition determination from the execution output of the circuit breaker. This avoids the influence of execution-end action delays or external interference on the synchronization determination results. Structurally, it enhances the reliability and controllability of parallel control.
3.Configurable Synchronization Stability Determination Mechanism
By setting the synchronization confirmation time and response characteristics, the system can be configured specifically according to the inertia and speed response characteristics of different generators, making the synchronization decision based on the stability trend rather than the instantaneous state, which is more suitable for complex or fluctuating grid environments.
4.Controllable intervention level of the speed control system
Under different working modes, the influence degree of the module on the main speed control system can be clearly defined. It can actively participate in speed correction during the automatic parallel operation process, or only exist as a synchronization determination unit during the debugging or controlled operation stage, avoiding excessive intervention in the main control logic.
5.Compatibility with multiple generations of Woodward control architectures
Through differentiated configuration of output signal characteristics and interface design, 9907-028 can seamlessly integrate into Woodward speed control and load control systems of different eras and types, thereby reducing the renovation costs when upgrading or adding parallel functionality to the old system.
6.Modular Architecture Independent of Voltage Control Loop
The synchronous control and voltage regulation maintain functional independence at the system level, allowing for flexible selection of excitation or voltage control schemes in engineering design. This also prevents the synchronous module from being affected by abnormal voltage circuits, thereby enhancing the overall robustness of the system.