Grid Disconnect Control for Seamless BESS Power Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Battery energy storage systems (BESS) fail to provide a seamless transition when disconnecting or connecting to the electrical distribution system, leading to temporary blackouts due to slow switchgear response in grid failures, which can have adverse consequences for critical applications.
Innovation Solution
An electrical distribution system with a battery energy storage system, an electrical switchgear device, and an electronic controller configured to detect voltage vector shifts and automatically disconnect the grid power source, ensuring timely power supply from the battery system using virtual-synchronous generator control mode, and reconnect when grid power is restored.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional switchgear is used for disconnection, then the system structure is simple, but the disconnection speed is too slow causing temporary blackouts
Solution Approach 1:
The patent replaces traditional mechanical switchgear with an electronic switching system using IGBTs (Insulated Gate Bipolar Transistors) controlled by microcontrollers. This electronic substitution enables disconnection speeds in the range of 2-5 milliseconds, dramatically faster than mechanical switchgear, while maintaining system controllability through electronic control circuits and synchronization algorithms.
2Reliability
If fast electronic switching is implemented, then disconnection speed improves, but device complexity increases
Solution Approach 1:
The patent implements feedback control through voltage and current sensors that continuously monitor system parameters. The microcontroller processes this feedback information to adjust switching timing and synchronize the battery system with the grid, ensuring seamless transition. The system also incorporates feedback from voltage vector shift detection to trigger disconnection events accurately.
Solution Approach 2:
The patent introduces an intermediary electronic control system with IGBTs and control circuits that mediate between the grid power source and the load. This intermediary layer enables precise control of the switching process, managing the complexity of fast electronic switching while providing reliable power transition. The control system acts as a bridge, coordinating between grid detection, switchgear operation, and battery system activation.
3Measurement precision
If voltage vector shift detection is used, then fault detection precision improves, but measurement complexity increases
Solution Approach 1:
The patent replaces complex physical measurement methods with electronic voltage vector analysis. The system uses microcontrollers to calculate voltage vectors from three-phase voltage measurements and detects shifts in these vectors to identify grid failures. This computational approach simplifies the detection process while maintaining high precision, avoiding the need for complex physical sensors or mechanical detection mechanisms.
Data Source
AI summary
An electrical distribution system is configured to supply electric power to an electric load and includes a feeder, a battery energy storage system, an electrical switchgear device and an electronic controller. The switchgear device is configured to selectively connect the connection point to the feeder, wherein the electronic controller is configured to: detect an electric fault representative of a power loss event on the grid power source; upon detecting an electric fault, automatically open the electrical switchgear device to disconnect the grid power source from the feeder; and ensure that the battery system supplies electric power to the electric load while operating in a virtual-synchronous generator control mode.