Battery Storage Formulation for Faster Day-Ahead SCUC
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems and methods for battery storage integration in Regional Transmission Organizations (RTOs)/Independent System Operators (ISOs) day ahead market clearing cases face challenges due to the mutual exclusiveness of charging and discharging modes, necessitating non-convex continuous constraints or binary variables, which impact computational performance and efficiency.
Innovation Solution
A battery storage formulation with convex relaxation and tightened SOC constraints, combined with warm start and lazy constraint techniques, is introduced to improve computational performance by ensuring mutual exclusivity of charging and discharging modes, using valid inequalities and binary variables to enhance the effectiveness of the solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If binary variables are used to ensure mutual exclusiveness of charging and discharging modes, then the physical constraints are satisfied, but the computational performance and solving time deteriorate
Solution Approach 1:
The patent transforms the binary variable formulation into a continuous variable formulation by changing the parameter type. This is achieved by using complementarity constraints and valid inequalities to model the mutual exclusiveness of charging and discharging modes without requiring discrete binary variables, thereby maintaining physical constraints while improving computational performance
Solution Approach 2:
The patent replaces the mechanical binary variable switching mechanism with a mathematical formulation using complementarity constraints and valid inequalities. This substitution eliminates the need for discrete optimization while preserving the physical reality that a battery cannot charge and discharge simultaneously, thus resolving the contradiction between constraint satisfaction and computational efficiency
2Reliability
If non-convex continuous constraints are used to model mutual exclusiveness, then the physical reality is captured, but the optimization problem becomes computationally intractable
Solution Approach 1:
The patent changes the mathematical formulation from non-convex continuous constraints to a convex formulation by using valid inequalities and complementarity constraints. This transformation maintains the physical accuracy of mutual exclusiveness while ensuring the optimization problem remains computationally tractable through convex optimization techniques
Solution Approach 2:
The patent introduces valid inequalities as intermediary constraints that mediate between the physical requirement of mutual exclusiveness and the computational need for convexity. These inequalities act as a bridge, capturing the essential physical behavior while maintaining mathematical tractability for efficient optimization
Data Source
AI summary
A method, system and computer-readable medium of directed towards improving battery storage is provided. In some embodiments, battery storage formulations are provided and an impact of the constraints on the computational performance of security constrained unit commitment (SCUC) is determined. For example, binary variables may be generally required due to mutual exclusiveness of charging and discharging modes. In some embodiments, valid inequalities may be used to improve state of charge (SOC) constraints. Adding batteries to the Regional Transmission Organizations (RTOs)/Independent System Operators (ISOs) day ahead market clearing cases may reveal an impact of binary variables and the valid inequalities on SCUC solving time. Warm start and lazy constraint techniques may be applied to improve the performance and make the valid inequalities more effective, reducing computation time to acceptable levels for implementation.


