Parallel Branch-Cut-Price Algorithm for Stochastic Unit Commitment

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Solution Overview

Problem

Conventional methods for solving stochastic unit commitment problems in the energy industry are inefficient due to their inability to effectively handle uncertainties and complexities introduced by renewable generation, energy storage, and demand response, leading to suboptimal solutions and high computational costs.

Innovation Solution

A parallel branch-cut-price algorithm is developed that exploits problem structure and leverages parallel computing, using techniques such as asynchronous processing, early termination, and dual weighting to iteratively generate candidate columns and solve pricing problems, maintaining a list of best lower bounds and using weighted dual solutions to improve computational efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If general-purpose solvers are used to solve stochastic unit commitment problems, then the problems can be solved without requiring specialized algorithms, but the computational time and efficiency are significantly increased

Engineering Contradiction:
Improvesolver applicabilityVSAvoidcomputational efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the stochastic unit commitment problem into multiple scenario subproblems that can be solved independently and in parallel. The master problem coordinates these scenario problems through column generation, allowing the algorithm to exploit the problem's decomposable structure to improve computational efficiency while maintaining solution quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a scenario dimension to the traditional unit commitment problem formulation. By formulating the problem in terms of multiple scenarios with different uncertainty realizations, the algorithm can process problems in parallel across the scenario dimension, significantly improving computational throughput for large-scale stochastic problems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If conventional sequential algorithms are used, then the algorithm implementation is simpler, but the computational time for large-scale problems is excessive

Engineering Contradiction:
Improvealgorithm complexityVSAvoidcomputational time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The patent performs preliminary actions by pre-generating scenario data and pre-processing the problem structure before the main optimization process. The column generation framework is set up in advance with pre-defined scenario trees and parameter structures, allowing the algorithm to focus computational effort on the core optimization iterations rather than data preparation during execution.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates multiple copies of the pricing subproblem that can be solved independently for different scenarios and columns. These copied subproblems are then aggregated in the master problem, allowing parallel computation across multiple processing units while maintaining the integrity of the overall optimization process.

Inventive Principle:
Principle #26Copying

3Ease of manufacture

If the problem structure is not exploited, then the algorithm is easier to implement, but the solution quality and computational performance deteriorate

Engineering Contradiction:
Improvealgorithm implementation easeVSAvoidsolution quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by treating different parts of the stochastic unit commitment problem with specialized algorithms tailored to their specific characteristics. The master problem uses column generation techniques appropriate for its structure, while scenario subproblems use pricing algorithms optimized for their local constraints and objectives, resulting in improved overall solution quality.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent dynamically changes parameters during the optimization process, including dual multipliers, column costs, and scenario weights. These parameter changes guide the column generation process to focus on the most critical decisions and scenarios, improving solution quality by adaptively adjusting the optimization focus based on problem state.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS9031798B2Systems and methods for solving large scale stochastic unit commitment problems
Publication Date: 2015.05.12 INTERNATIONAL BUSINESS MACHINE CORPORATION
  • US9031798B2 patent drawing
  • US9031798B2 patent drawing
  • US9031798B2 patent drawing

AI summary

The present disclosure relates generally to computational solution algorithms (and associated systems and methods) applied to a stochastic unit commitment problem. In one example, the computational solution algorithms (and associated systems and methods) may be applied to the energy industry.