Grid Connection Voltage Support Estimation Using Dual SCR Indexes
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Solution Overview
Problem
Existing methods for estimating the voltage support strength of renewable energy grid-connected power systems lack accuracy, practicality, and speed, and are inconsistent due to varying construction methods, making it difficult to ensure safe and stable operation.
Innovation Solution
A method is developed to estimate voltage support strength by determining first and second short-circuit ratio indexes based on short-circuit capacity, equivalent grid connection capacity, and voltage variation, using a critical short-circuit ratio as a reference, to provide an accurate, rapid, and intuitive assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional SCR calculation methods are used, then the voltage support strength can be estimated, but the accuracy and practicability are insufficient due to multiple inconsistent construction methods
Solution Approach 1:
The patent segments the SCR calculation into two distinct indexes: the first SCR index based on short-circuit capacity ratios, and the second SCR index based on voltage variation. This segmentation resolves the inconsistency of traditional single-method approaches by providing multiple specialized measurement perspectives that can be used independently or complementarily, thereby improving accuracy without requiring a single complex unified method.
Solution Approach 2:
The patent introduces parameter changes by defining SCR through different physical quantities: the first index uses short-circuit capacity parameters (SCC of AC system and equivalent grid connection capacity), while the second index uses voltage variation parameters. This allows the system to adapt the measurement approach based on available data and specific operational conditions, improving both accuracy and practicability.
2Reliability
If multiple construction methods are used to calculate CSCR, then comprehensive assessment is possible, but the results become inconsistent and difficult to interpret
Solution Approach 1:
The patent extracts the core essence of CSCR calculation by identifying the critical relationship between short-circuit capacity and maximum transmission power. Instead of using multiple complex construction methods, it extracts the fundamental parameters (SCC, equivalent maximum transmission power) and establishes a unified calculation approach, thereby improving consistency while maintaining practicality.
Solution Approach 2:
The patent creates a universal CSCR calculation method that can be applied across different renewable energy grid-connected systems regardless of specific configuration variations. By using standardized parameters (SCC, equivalent maximum transmission power) and a unified formula, the method achieves multi-functionality and consistency across diverse应用场景, making it both reliable and easy to operate.
3Measurement precision
If detailed and accurate measurement methods are used, then the voltage support strength can be precisely estimated, but the calculation process becomes time-consuming and less rapid
Solution Approach 1:
The patent applies preliminary action by pre-defining the two SCR indexes and the CSCR calculation framework before actual voltage support strength estimation is needed. The indexes are structured to use readily available system parameters (short-circuit capacity, voltage measurements, maximum transmission power), eliminating the need for complex real-time calculations and enabling rapid assessment while maintaining accuracy.
Solution Approach 2:
The patent uses simple, easily obtainable measurement data (short-circuit capacity values, voltage variations, transmission power) as disposable inputs for the SCR indexes. These parameters can be quickly measured or retrieved without requiring expensive, time-consuming detailed system analysis, thereby achieving accurate estimation with minimal time investment.
Data Source
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AI summary
A method for estimating a voltage support strength of a renewable energy grid-connected power system. A first short-circuit ratio index of a renewable energy grid-connected power system is determined based on a short-circuit capacity provided for a grid connection point by an alternating-current system, An equivalent grid connection capacity of renewable energy at the grid connection point is determined. A second short-circuit ratio index of the renewable energy grid-connected power system is determined based on a voltage variation at a position where the renewable energy is connected to the grid connection point. A critical short-circuit ratio of the renewable energy grid-connected power system determined based on a parameter of the alternating-current system and an equivalent maximum transmission power. A voltage support strength provided by the renewable energy grid-connected power system at the grid connection point is determined based on the first and second short-circuit ratio indexes and the critical short-circuit ratio.