Integrated STATCOM Energy Storage Using Dormant Converter Arms
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current STATCOM solutions fall short in meeting new grid code requirements for 100% negative sequence compensation and fault support, particularly in providing virtual inertia and active power support, due to inefficiencies and additional component needs in integrating Energy Storage with STATCOM.
Innovation Solution
The integration of Energy Storage with STATCOM using intermittently usable chain-link arms as power electronic interfaces, allowing for efficient active and reactive power support by utilizing dormant converter cells and arms during non-STATCOM operation periods, thereby reducing the need for additional components and enhancing power handling capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Energy Storage is integrated with STATCOM using separate converters, then both reactive and active power support are provided, but additional components (DC/AC converter, line reactors, output filter) and increased device complexity are required
Solution Approach 1:
The patent merges the Energy Storage converter and STATCOM converter into a single integrated power electronic converter, sharing common components including the DC/AC converter, line reactors, and output filter. This consolidation provides both reactive and active power support while eliminating the need for separate converter systems and reducing overall device complexity
Solution Approach 2:
The integrated converter system performs multiple functions simultaneously: it provides reactive power compensation for voltage support, active power support for frequency regulation, and energy storage functions. The single converter system serves as a universal interface that handles both STATCOM and energy storage operations without requiring dedicated separate converters
2Reliability
If STATCOM is designed to meet new grid codes for 100% negative sequence compensation, then fault support capability is improved, but existing solutions fall short in providing sufficient virtual inertia and active power support
Solution Approach 1:
The patent combines the STATCOM function with Energy Storage in a single integrated system, enabling simultaneous provision of reactive power for fault support and active power for virtual inertia. The shared converter architecture allows the system to meet 100% negative sequence compensation requirements while also providing the active power support needed for virtual inertia, something that separate systems struggled to achieve
3Loss of energy
If converter arms are dynamically connected and disconnected during operation, then reduced losses are achieved, but not all chain-link arms are in operation all the time requiring alternative usage
Solution Approach 1:
The patent makes the converter arms universal by enabling them to switch between STATCOM operation and Energy Storage interface functions. Chain-link arms that are dynamically disconnected during STATCOM operation are reassigned to serve as power electronic interfaces for the Energy Storage system, ensuring continuous utilization of all converter components and eliminating idle capacity
Solution Approach 2:
The system dynamically reconfigures the function of converter arms based on operational requirements. During periods when chain-link arms are not needed for STATCOM reactive power compensation, they are dynamically switched to provide active power interface functions for the Energy Storage system, optimizing the dynamic utilization of all converter components
Data Source
Figure 1a~1b
Figure 1c
Figure 1d~1e
AI summary
A STATCOM arrangement (10) comprises a STATCOM (1) configured to be connected to a three-phase AC grid (11). The STATCOM comprises a plurality of converter arms (3), each converter arm comprising a plurality of series connected converter cells (5). The STATCOM arrangement also comprises an Energy Storage System, ESS, (20) comprising an energy storage, ES, (21) and energy storage switches (SES) for connecting the ES to the grid (11) via the converter arms. The plurality of converter arms comprises a plurality of intermittently usable chain-links of the series connected converter cells. Each of said chain-links is used for STATCOM operation during a part of a fundamental operation cycle of the STATCOM. The energy storage switches connect the ES to at any point in time via one of said chain- links which is not used for the STATCOM operation at said time point.