Secure Optimal Power Flow with Voltage Stability Ranking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for solving optimal power flow (OPF) problems in electric power systems face challenges in achieving both economic and secure solutions, particularly in handling large-scale systems with numerous contingencies, leading to computational inefficiencies and potential instability.
Innovation Solution
The SuperOPF-VS process combines a SuperOPF process for optimal power flow computation with a voltage stability analysis to rank contingencies and compute preventive controls, focusing on active thermal limits and sensitivity-based discrete control handling, thereby reducing the complexity of the OPF problem and enhancing scalability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing OPF solvers are used to achieve optimal solution for pre-contingency system, then economic optimality is improved, but system security and stability are compromised
Solution Approach 1:
The patent segments the security analysis by ranking contingencies based on voltage stability indices and focusing computational resources on the most critical contingencies rather than evaluating all contingencies equally. This segmentation allows the system to achieve security constraints with reduced computational burden by prioritizing analysis of top-ranked contingencies that pose the greatest stability risk.
Solution Approach 2:
The patent performs preliminary voltage stability analysis and contingency ranking before the main OPF optimization. By pre-computing stability indices and ranking contingencies in advance, the system prepares security constraint information that guides the subsequent OPF solution process, avoiding the need for repeated full stability analyses during optimization iterations.
2Reliability
If voltage stability constraints are incorporated into OPF problem, then system security is improved, but problem complexity increases
Solution Approach 1:
The patent transforms voltage stability constraints into algebraic inequalities using voltage stability indices and load margin parameters. By changing the mathematical representation from differential-algebraic equations to algebraic constraints, the problem complexity is reduced while maintaining the essential voltage stability requirements in the OPF formulation.
Solution Approach 2:
The patent introduces voltage stability indices and contingency ranking as intermediary measures that bridge the gap between security requirements and OPF optimization. These intermediaries translate complex stability analysis into simplified constraint forms that can be efficiently incorporated into the OPF problem without requiring full transient stability simulations.
3Reliability
If comprehensive contingency analysis is performed, then system security is improved, but computational time increases
Solution Approach 1:
The patent segments the contingency set into ranked categories based on voltage stability impact, focusing detailed analysis on the most critical contingencies. By dividing contingencies into priority levels and applying different analysis depths to different segments, the system achieves comprehensive security coverage for critical cases while avoiding excessive computational spending on low-impact contingencies.
Solution Approach 2:
The patent applies partial contingency analysis by evaluating only the top-ranked contingencies that pose the greatest stability risk, rather than performing exhaustive analysis on all possible contingencies. This partial action approach provides sufficient security coverage for the most critical scenarios while significantly reducing computational time compared to complete contingency enumeration.
Data Source
AI summary
An optimal power flow (OPF) problem formulates constraints and operation of an electric power system. A method and system is provided for generating a secure OPF solution that solves the OPF problem. A list of contingencies is created from system data. An OPF solution is computed for the electric power system to optimize an objective function value under the constraints of the electric power system. Voltage stability analysis is performed on the electric power system that operates in states represented by the OPF solution. Then the contingencies are ranked according to load margins of the electric power system. If there is at least an insecure contingency with a non-positive load margin in the list of contingencies, a set of preventive controls are computed and applied to control components in the electric power system. The method is performed iteratively to obtain the secure OPF solution.