Microgrid Energy Storage Switching for Seamless Islanded Operation
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Solution Overview
Problem
Existing power grid systems experience delays when switching from grid-connected mode to standalone mode due to generator startup times, leading to potential load terminal tripping or malfunction from sudden voltage drops.
Innovation Solution
A power grid system comprising a bus, a switching module with a switching device, and an energy storage system that can operate in current source and voltage source modes. The energy storage system receives a tripped signal from the switching module, switching to voltage source mode to stabilize the grid during standalone operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a generator is used as backup voltage supply when switching to standalone mode, then the microgrid can maintain voltage supply, but the startup of the generator causes delay in switching of the voltage source
Solution Approach 1:
The energy storage system is pre-charged during grid-connected operation and is ready to immediately provide voltage support when the main grid fails, eliminating the startup delay associated with generators. The system performs the necessary preparation (charging) in advance so that no time is lost during the actual switching event.
Solution Approach 2:
The energy storage system acts as an intermediary between the main grid and the loads, providing a seamless transition during grid failures. Instead of directly switching from main grid to generator (which causes delay), the energy storage system mediates the transition by immediately picking up the voltage support role when the grid fails.
2Reliability
If a generator is used as backup voltage supply, then the microgrid can operate in standalone mode, but the sudden voltage drop during switching may cause load terminal tripped or malfunctioned
Solution Approach 1:
The energy storage system provides a cushioning effect by being pre-charged and ready to immediately support voltage when grid failure occurs. This prevents the sudden voltage drop that would otherwise occur during the transition from grid-connected to standalone mode, protecting sensitive loads from malfunctions.
Solution Approach 2:
The system converts the potential harm of grid failure into a benefit by using the energy storage system's pre-stored energy to maintain voltage stability during the transition. The failure scenario is transformed into an opportunity to demonstrate the resilience and stability of the microgrid system.
3Loss of time
If the energy storage system switches operation modes quickly upon receiving tripped signal, then the switching delay is reduced, but the system must handle rapid mode transition requirements
Solution Approach 1:
The control system uses feedback from the grid status (tripped/closed signals) to automatically trigger mode transitions in the energy storage system. When the switching device detects grid failure, it sends a tripped signal that immediately prompts the energy storage system to switch from charge mode to discharge mode, enabling rapid response without complex manual control.
Data Source
AI summary
The present disclosure relates to a power grid system and method of managing the same. According to the present invention, a power grid system is provided. The power grid system is adapted to supply electric power to at least one load unit, and the power grid system comprises a bus, a switching module, and an energy storage system coupled to the bus. The at least one load unit is coupled to the bus. The switching module comprises a switching device. The switching device is connected between the bus and a main grid. The energy storage system is configured to operate in a current source mode and a voltage source mode, and it is configured to receive a tripped signal from the switching module. The energy storage system is configured to switch to the voltage source mode when the energy storage system receives the tripped signal.