Constrained Genetic Algorithm for Dynamic Economic Load Dispatch

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Solution Overview

Problem

Dynamic economic load dispatch (DELD) problems in power systems are challenging due to non-linear fuel cost functions, ramp rate limits, and prohibited operating zones, which traditional genetic algorithms struggle to handle effectively, leading to inefficient solutions.

Innovation Solution

A constrained genetic algorithm (CGA) is developed to address these challenges by modifying initialization, crossover, and mutation operators to keep solutions within feasible regions, accommodate dynamic constraints, and ensure load equality, thereby solving DELD problems without additional optimization methods like quadratic programming.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional genetic algorithms are used to solve DELD problems, then the search space can be explored, but the algorithm fails to handle non-linear fuel cost functions, ramp rate limits, and prohibited operating zones effectively

Engineering Contradiction:
Improveability to handle non-linear fuel cost functions and dynamic constraintsVSAvoidsolution accuracy and optimality
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies dynamics by making the genetic algorithm adaptive to changing constraints and objectives. The algorithm dynamically adjusts its search strategy based on the non-linear fuel cost functions and time-varying load demand patterns, allowing it to handle the dynamic nature of power system optimization problems effectively

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes key parameters of the genetic algorithm including population size, mutation rate, and crossover probability to optimize performance. It also transforms the objective function to incorporate penalty terms for constraint violations, enabling the algorithm to handle non-linear fuel cost functions and dynamic constraints accurately

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the dispatch problem is divided into multiple time intervals to handle dynamic constraints, then the overall optimization can be achieved, but the search space becomes narrow and uneven

Engineering Contradiction:
Improveconstraint satisfactionVSAvoidsearch space complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the dispatch problem into multiple time intervals, allowing dynamic constraints to be applied at each interval. This segmentation enables the algorithm to handle time-varying load demand and ramp rate limits while maintaining a manageable search space structure through systematic decomposition

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces penalty functions as intermediaries to handle constraint violations. These penalty terms act as mediators between the optimization objective and the dynamic constraints, transforming the complex constrained optimization problem into a series of easier-to-solve unconstrained or lightly-constrained subproblems

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If evolutionary methods assign low fitness to constraint violating solutions, then constraints can be satisfied, but information sharing between individuals and generations is heavily restricted

Engineering Contradiction:
Improveconstraint satisfactionVSAvoidinformation sharing efficiency
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent converts the harmful effect of constraint violations into a beneficial learning opportunity by using penalty functions. Instead of simply eliminating invalid solutions, the algorithm uses penalty terms to guide the search toward feasible regions, allowing information about constraint boundaries to be shared and learned across generations

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent implements feedback mechanisms through penalty functions that provide continuous information about constraint violations. This feedback loop allows the genetic algorithm to learn from constraint violations and adjust its search strategy, maintaining information flow while ensuring constraint satisfaction

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS7752150B2Dynamic economic load dispatch by applying dynamic programming to a genetic algorithm
Publication Date: 2010.07.06 HONEYWELL BEIJING TECH SOLUTIONS LAB
  • US7752150B2 patent drawing
  • US7752150B2 patent drawing
  • US7752150B2 patent drawing

AI summary

In an embodiment, a system and method provide a constraint on a genetic algorithm, and further provide dynamic programming capability to the genetic algorithm. The system and method then allocate load demand over a finite number of time intervals among a number of power generating units as a function of the constraint on the genetic algorithm and the dynamic programming capability of the genetic algorithm.