Contingency Screening in Multi-Control Area Power Systems
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Solution Overview
Problem
Current contingency analysis in large-scale electrical power systems is computationally demanding due to the need for full AC power flow calculations for each contingency, which is time-consuming and limits the efficiency of Security Constrained Unit Commitment (SCUC) and Security Constrained Economic Dispatch (SCED) algorithms.
Innovation Solution
A method involving the generation of a mesh model, partitioning into areas, transforming these areas into tree structures, connecting them with tie-lines to create a joined reference frame, and performing a multi-area transformation, allowing for modular and distributed power flow calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full AC power flow calculations are performed for each contingency, then measurement precision and reliability are improved, but calculation time and computational complexity increase significantly
Solution Approach 1:
The power system is divided into multiple control areas, and the contingency analysis is segmented into hierarchical levels (system-level and area-level). This allows the large-scale AC power flow calculation to be broken down into smaller, more manageable sub-calculations that can be performed independently and in parallel, significantly reducing overall computation time while maintaining accuracy.
Solution Approach 2:
The method performs preliminary DC power flow calculations to identify critical contingencies and screen out non-critical cases before executing full AC power flow calculations. This preliminary screening step filters the contingency set, ensuring that computationally intensive AC calculations are only performed on contingencies that truly require detailed analysis, thus reducing total calculation time.
2Productivity
If DC power flow approximation is used for contingency screening, then calculation speed is improved, but measurement precision deteriorates
Solution Approach 1:
The method dynamically selects the appropriate calculation method (DC approximation or full AC power flow) based on the specific contingency characteristics and system state. For routine contingencies, DC power flow provides sufficient accuracy with high speed. For critical contingencies identified through DC screening, the system transitions to full AC power flow calculations to ensure precision, creating a dynamic, adaptive calculation strategy.
Solution Approach 2:
DC power flow serves as an intermediary screening tool between the initial contingency list and the final AC power flow analysis. It acts as a filter that identifies which contingencies warrant detailed AC analysis, providing a computationally efficient intermediate step that maintains sufficient accuracy for screening purposes while enabling faster decision-making.
3Reliability
If contingency analysis is performed for all possible outages, then system security and reliability are improved, but device complexity and computational burden increase
Solution Approach 1:
The contingency analysis algorithm is segmented into multiple processing levels: system-level DC power flow for initial screening, identification of critical contingencies, and area-level detailed analysis. This segmentation reduces algorithmic complexity by avoiding the need to execute full AC power flow for every possible contingency, while still maintaining comprehensive security assessment through the hierarchical structure.
Solution Approach 2:
The algorithm performs preliminary DC power flow calculations and contingency screening to identify and prioritize critical contingencies before executing detailed AC power flow analysis. This preliminary action reduces the number of full AC calculations required, simplifying the overall algorithm while ensuring that all critical security issues are captured through the systematic screening process.
Data Source
AI summary
A new approach in contingency analysis is presented based on a modular method for power flow calculation. The proposed method exploits reuse of power flow data for modules not affected by an outage. The method minimizes the number of necessary computations and matrix inversions in contingency analysis; this is achieved by recalculating only the modules affected by the change and reusing data from the original system for all other modules.