Generator Synchronization Using a Common External Reference
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Solution Overview
Problem
Conventional methods for synchronizing multiple generators to an AC bus require sequential synchronization, which is time-consuming and can lead to prolonged power outages, especially in critical infrastructure settings where rapid power restoration is necessary.
Innovation Solution
Implementing synthetic synchronization, where generators synchronize to a common external signal or reference, such as a GPS time signal, allowing parallel synchronization independent of bus voltage and frequency, enabling simultaneous connection to the bus upon power loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sequential synchronization method is used, then generators can be synchronized safely to the AC bus, but the synchronization process is time-consuming and prolongs power outages
Solution Approach 1:
The system performs preliminary synchronization actions by having each generator synchronize to a common external reference signal (such as GPS time signal) before actual bus connection. This preliminary synchronization establishes the correct phase, frequency, and voltage relationships in advance, allowing generators to be ready for simultaneous parallel connection without requiring time-consuming sequential synchronization procedures.
Solution Approach 2:
The patent introduces a common external reference signal as an intermediary that mediates the synchronization process. Instead of directly synchronizing generators to each other or to the bus sequentially, each generator independently synchronizes to this common reference signal, which then enables simultaneous safe connection to the bus. The reference signal acts as a mediator that coordinates all generators' synchronization independently of the bus state.
2Reliability
If sequential synchronization is performed, then generators can be connected to the bus one by one, but additional breaker operations are required and the process becomes complex
Solution Approach 1:
Breakers are closed in advance before synchronization is complete. The system prepares all generator breakers for simultaneous closure once synchronization to the common reference is achieved, eliminating the need for sequential breaker operations and reducing operational complexity.
Solution Approach 2:
The traditional sequence is inverted: instead of synchronizing then closing breakers sequentially, the system closes all breakers simultaneously after parallel synchronization to the common reference is achieved. This reversal of the traditional sequence simplifies the operation by eliminating multiple sequential breaker maneuvers.
3Reliability
If generators are synchronized sequentially to the AC bus, then proper phase and frequency matching is achieved, but the synchronization process cannot begin until bus voltage is present
Solution Approach 1:
A common external reference signal (such as GPS time signal) serves as an intermediary that enables synchronization to begin independently of bus voltage. This reference signal provides the necessary phase and frequency information allowing generators to synchronize in advance before being connected to the bus, eliminating the delay of waiting for bus voltage.
Solution Approach 2:
Generators perform preliminary synchronization to the common external reference signal before actual bus connection occurs. This preliminary action establishes correct phase and frequency relationships in advance, allowing the synchronization process to start immediately when needed rather than waiting for bus voltage to be present.
Data Source
AI summary
The present disclosure contemplates a method for synchronizing a large number of generators on an AC bus by synchronizing each generator's output to a nominal output that is generated from a common external source. For example, each generator, using a high speed communication signal, can synchronize to a nominal output provided by a master generator, or centralized command module. In another example, each generator can generate its own nominal output referenced to a common external time signal, such as a global positioning system (GPS) signal, or other reference. By synchronizing independently of bus voltage and frequency, the generators are able to synchronize in parallel, instead of serially.