Online Power Dispatch with AC Flow Constraints
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing online economic dispatch methods for power systems with renewable energy and storage face challenges due to the use of DC power flow equations, which do not accurately represent AC power flows, leading to potential violations of thermal and voltage limits, and require more accurate and efficient computational methods to minimize operational costs.
Innovation Solution
A method that incorporates AC power flow equations and thermal limits into the online multi-period power dispatch problem, using a three-stage solution methodology involving scenario reduction, decomposition of the problem into single-period subproblems, and a homotopy-enhanced primal-dual interior point method to ensure robust and efficient solution of the dispatch problem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If DC power flow equations are used for online economic dispatch, then computational speed is improved, but accuracy of power flow representation deteriorates leading to potential violations of thermal and voltage limits
Solution Approach 1:
The patent transforms the non-convex AC power flow optimization problem into a convex problem by changing the parameterization approach - using squared magnitudes of voltage and line flows as decision variables, and applying a variable substitution that linearizes the AC power flow equations while maintaining accuracy. This resolves the contradiction by achieving both computational efficiency and accuracy.
2Measurement precision
If AC power flow equations and thermal limits are incorporated into the power dispatch problem, then accuracy and executability of the solution is improved, but computational complexity and difficulty of solving increases
Solution Approach 1:
The patent changes the mathematical parameters and structure of the optimization problem by using squared magnitudes as variables and applying variable substitutions that transform the non-convex AC power flow equations into linear constraints. This maintains solution accuracy while dramatically reducing computational complexity, enabling real-time implementation.
3Reliability
If conventional interior point method is used to solve the power dispatch problem, then theoretical convergence is guaranteed, but computational robustness deteriorates due to divergence and slowness issues
Solution Approach 1:
The patent applies a variable substitution that transforms the original optimization variables into new parameters that linearize the problem structure. This parameter transformation makes the problem amenable to efficient solution methods that guarantee both convergence and robustness in practice, eliminating the divergence and slowness issues of conventional methods.
Data Source
AI summary
A computer system provides real-time control of power dispatch for a power system. The power system includes power generators, renewable power generators, load, and storage devices interconnected by a power grid. The computer system obtains input data, and solves an online multi-period power dispatch problem formulated from the input data and incorporates AC power flow in the power grid. The computer system generates control signals according to a solution of the online multi-period power dispatch problem, and sends the control signals to controllers of the power generators and the storage devices. In every time period during operation of the power system, the computer system updates the solution, generates updated control signals according to the updated solution, and sends the updated control signals to the controllers to continuously operate the power system with minimized operational cost while fully utilizing renewable power output.