Grid Connection Voltage Support Estimation Using SCR and CSCR
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Solution Overview
Problem
Current methods for estimating the voltage support strength of renewable energy grid-connected power systems are inaccurate, impractical, and lack rapidity, due to inconsistencies in calculation methods, making it difficult to ensure safe and stable operation.
Innovation Solution
A method and system that determine the first and second short-circuit ratio indices based on short-circuit capacity, equivalent grid connection capacity, and voltage variation, combined with critical short-circuit ratio calculations, to estimate voltage support strength using preset rules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional SCR calculation methods are used, then the voltage support strength estimation is provided, but the accuracy and practicability are contradictory 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 ratio, and the second SCR index based on voltage variation. This segmentation resolves the contradiction by providing multiple specialized calculation methods for different scenarios, improving accuracy without requiring a single overly complex universal method.
Solution Approach 2:
The patent introduces the CSCR (critical short-circuit ratio) as a new parameter to serve as a reference threshold. By comparing the calculated SCR indexes against this critical threshold, the system achieves accurate voltage support strength estimation while maintaining practical simplicity through clear threshold-based decision rules.
2Adaptability or versatility
If multiple construction methods are used for CSCR calculations, then various approaches are available, but the calculations become inconsistent and difficult to provide an accurate, rapid, and practical estimation method
Solution Approach 1:
The patent creates a universal estimation framework that can handle multiple calculation approaches through the two SCR indexes and CSCR comparison mechanism. This framework provides adaptability for different calculation methods while ensuring reliability through consistent threshold-based evaluation rules, resolving the contradiction between versatility and consistency.
3Measurement precision
If the voltage support strength estimation method is made more accurate, then the safe and stable operation is ensured, but the calculation becomes less rapid and practical
Solution Approach 1:
The patent achieves both accuracy and speed by transforming the estimation problem into parameter comparison tasks. By calculating SCR indexes and comparing them against the CSCR threshold parameter, the system obtains accurate results through simple arithmetic operations and threshold comparisons, maintaining high calculation speed while ensuring reliability.
Data Source
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.