Energy Storage PCS Control for Transient Grid Fault Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing proportion of grid-connected new energy-based power generation systems, such as photovoltaic and wind power systems, has led to a decrease in system inertia and short-circuit current, increasing the risk of power system instability, necessitating improved transient current overload capability in converter grid-forming systems.
Innovation Solution
An energy storage power generation system with a power conversion system architecture that utilizes the short-time overload capability of semiconductor devices, allowing for a simplified system design, increased efficiency, and reduced component costs by optimizing the system architecture to support the power grid during transient overloads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the quantity of power conversion systems is increased to provide transient current overload capability for grid support, then the grid stability performance is improved, but the system complexity and component costs increase
Solution Approach 1:
The patent implements dynamic operating mode switching between steady-state and transient-state modes based on real-time detection of power grid conditions. The control device switches to transient-state mode when voltage or frequency deviations are detected, enabling the power conversion systems to dynamically adjust their output characteristics and provide transient current overload capability only when needed, thus maintaining grid stability without permanently increasing system complexity
Solution Approach 2:
The patent changes the operating parameters of power conversion systems by switching between different operating modes. In transient-state mode, the systems operate with different current and power parameters compared to steady-state mode, allowing them to provide enhanced transient current overload capability during grid disturbances while returning to normal parameters when the grid is stable
2Reliability
If the quantity of power conversion systems is increased to provide transient current overload capability, then the transient current overload capability is improved, but the component costs increase
Solution Approach 1:
The system dynamically switches between operating modes to provide transient current overload capability only when grid disturbances occur. This dynamic approach allows existing power conversion systems to temporarily operate in transient-state mode with enhanced capability, eliminating the need to permanently install additional systems or oversized components that would increase costs
Solution Approach 2:
The existing power conversion systems serve dual purposes: normal power conversion during steady-state and transient current overload provision during disturbances. The systems self-adjust their operating characteristics based on grid conditions, providing grid support functionality without requiring separate dedicated components
3Reliability
If the power conversion systems operate in transient-state mode with higher output power, then the capability to support power grid is improved, but the semiconductor device overload stress increases
Solution Approach 1:
The system operates in transient-state mode with enhanced output capability only during brief periods when grid disturbances are detected. The control device monitors voltage and frequency continuously and switches modes based on real-time conditions, ensuring that semiconductor devices experience overload stress only temporarily during actual grid events rather than continuously
Solution Approach 2:
The system detects grid disturbances in advance through continuous monitoring of voltage and frequency parameters. When deviations are detected, the control device proactively switches to transient-state mode before the disturbance fully develops, allowing the semiconductor devices to gradually adjust to higher stress levels rather than experiencing sudden extreme overload
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively supports the power grid during transient faults by quickly switching operating modes and utilizing the short-time overload capability of semiconductor devices, ensuring stable and reliable operation while reducing the number of power conversion systems and overall costs.
Implementation Method 1
The energy storage container includes a battery, configured to store electric energy
Implementation Method 2
the plurality of power conversion systems are configured to implement current conversion between the energy storage container and the power grid
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
An energy storage power generation system and a control method thereof are provided. The energy storage power generation system includes an energy storage container and a plurality of power conversion systems. Direct-current side ports of the plurality of power conversion systems are connected to the energy storage container, alternating-current side ports of the plurality of power conversion systems are connected in parallel and are configured to connect to a box-type transformer or a power grid, and the power conversion systems are configured to implement current conversion between the energy storage container and the box-type transformer or the power grid. When a transient fault occurs in the power grid, the plurality of power conversion systems may enter a transient-state operating mode from a steady-state operating mode, and a parallel expansion multiple of the energy storage power generation system is less than a transient overload multiple. According to this application, a physical characteristic of transient overloading and a short-time overload capability of the power conversion system are fully used, and the power grid is supported when a power grid fault is detected. This solution simplifies an architecture of the system and increases efficiency of the system. It is easy to understand that because a quantity of power conversion systems is reduced, costs of the system are also reduced.