Power Grid Switching Control for Accurate Reconnection Synchronization
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Solution Overview
Problem
Existing microgrid management systems face instability when switching from isolated to grid-connected operations due to unsynchronized electric power with the external power network, as they do not effectively manage the synchronization of power grids during reconnection.
Innovation Solution
A server manages power grids by determining a master and slave among power adjustment resources to synchronize electric power through master-slave control, prioritizing resources close to the connection point to ensure accurate synchronization and stability during grid-connection switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power adjustment resource distant from the grid-connection point is selected as the master, then the system can operate with available resources, but the inductance of the electric wire becomes high causing deviation between electric power of the first power grid and the second power grid
Solution Approach 1:
The patent applies local quality by selecting the master power adjustment resource based on its location relative to the grid-connection point. Specifically, it prioritizes resources closer to the connection point to minimize wire inductance and improve synchronization accuracy, while still allowing distant resources to serve as masters when necessary through the fallback mechanism.
Solution Approach 2:
The patent implements dynamics by making the master resource selection flexible and adaptive. The system dynamically adjusts the selection criteria based on the availability and state of power adjustment resources, allowing the master role to be assigned to different resources depending on current system conditions rather than being fixed.
2Reliability
If master-slave control is implemented for synchronization, then electric power stability is improved, but the system complexity increases due to the need for master and slave designation and control coordination
Solution Approach 1:
The patent applies preliminary action by designating the master and slave power adjustment resources before the grid-connection switching occurs. This advance designation allows the synchronization control to be pre-configured, reducing the complexity of real-time coordination during the actual switching event and improving reliability.
3Measurement precision
If power adjustment resources are used for synchronization control, then the synchronization accuracy is improved, but the communication requirements and system coordination complexity increase
Solution Approach 1:
The patent applies parameter changes by using power adjustment resources that can modify their output parameters (active power, reactive power, frequency) to achieve synchronization. By adjusting these parameters, the system can match the frequency and phase of the external power grid, improving synchronization accuracy while utilizing existing resource capabilities rather than adding complex dedicated synchronization equipment.
Data Source
AI summary
A first switching unit switches a first power grid from an isolated operation to a grid-connected operation. In switching the first power grid from the isolated operation to the grid-connected operation, the first switching unit determines a master and a slave among a plurality of power adjustment resources and allows the first power grid to be connected to the second power grid after master-slave control by means of the master and the slave such that electric power of the first power grid is in synchronization with electric power of the second power grid. The first switching unit preferentially selects as the master, a power adjustment resource close to a point of connection between the first power grid and the second power grid from among the plurality of power adjustment resources.