Distributed Grid Interconnection With GPS Phase Synchronization
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Solution Overview
Problem
Existing systems for interconnecting micro-grids with the main grid face challenges such as the need for large-scale central energy management systems, communication delays, limitations in interconnectable power capacity, and difficulties in supplying sufficient short-circuit current.
Innovation Solution
A cooperative autonomous distributed grid interconnection system that includes a synchronization checking circuit breaker, a grid interconnection controller, and cooperative autonomous distributed devices. These components work together to synchronize the cell grid with the main grid, allowing for independent operation while maintaining synchronous connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a central energy management system is used to control the micro-grid, then comprehensive control of the entire power system is achieved, but the system scale becomes large and communication delays occur
Solution Approach 1:
The patent divides the centralized energy management system into distributed control units (one for each power generation facility). Each control unit independently manages its local facility, eliminating the need for a large-scale centralized system while maintaining comprehensive control capability through coordinated operation of multiple autonomous units.
Solution Approach 2:
Each power generation facility is equipped with its own control unit that autonomously adjusts output voltage and phase based on local conditions and GPS time signals. The system serves itself through distributed autonomous control rather than relying on external centralized management, reducing communication requirements and system complexity.
2Adaptability or versatility
If an asynchronous interconnection power converter is used, then frequency and phase synchronization with the main grid is not required, but the interconnectable power capacity is limited and apparatus size increases
Solution Approach 1:
The patent changes the operating parameters of power generation facilities by adjusting output voltage and phase angles to achieve synchronous operation with the main grid. This allows the system to operate at higher power capacities without the limitations of asynchronous conversion, while the GPS-based time synchronization ensures accurate phase alignment.
3Ease of operation
If a fixed frequency control method is used, then independent micro-grid operation is simplified, but the system cannot follow steep fluctuations in the main grid
Solution Approach 1:
The patent implements feedback control where each power generation facility's output voltage and phase are continuously adjusted based on GPS time signals and grid conditions. This feedback mechanism allows the system to respond quickly to main grid fluctuations while maintaining stable operation, combining the simplicity of fixed-frequency control with the responsiveness needed for grid following.
Data Source
AI summary
In a cooperative autonomous distributed grid interconnection system, each of the cooperative autonomous distributed devices receives frequency information and phase information transmitted from the grid interconnection controller based on a standard time signal, or a combined signal of the frequency information and the phase information. When the synchronization checking circuit breaker is open, each or the cooperative autonomous distributed devices controls a voltage phase of the cell grid system so that the voltage phase of the cell grid system is synchronized with that of the main grid. When the synchronization checking circuit breaker is closed, each of the cooperative autonomous distributed devices controls a power flow between the main grid and the cell grid system.