Solving Optimization Problems Using MATLAB GA toolbox-Part 1

The GA tool box of MATLAB is good in solving hard optimization problems. It can be run form (i) GUI (Graphical  User Interface) mode or(ii) Command line Mode.


GA A Different Introduction

Genetic Algorithm or GA is one of th basic and powerful heuristic optimization algorithms.If you read any material on this algorithm you can observe the following points.

• 1.It is working on the population dynamics.
• 2.It is searching form a set of solutions(population) .
• 3.It does not need the derivative or continuous solution search space.
• 4.It doing some probabilistic operations like Reproduction,Cross Over,Mutation on the old  population to produce a new population.

MATLAB GA Toolbox

This toolbox contains some matlab files which can do the above described actions.This can be run in two modes.The GA toolbox is written as a minimization tool. Maximization problems also can be done by converting the Maximization problem as minimization problem.

1.GUI Mode

2.Command line Mode

Steps For Solving Optimization Problem 


To use the GA toolbox you need not know anything about Ga and its dynamics. All you should know is some fundamentals about optimization or operation research and basic matlab commands.


1. Model the optimization problem as a unconstrained  minimization problem.

2. Write the unconstrained minimization problem  as matlab function file.
3. Run the matalb ga tool box in a command line mode or GUI mode.




I am giving one example in GUI .It s problem of minimizing a  two variable quadratic function subject to a linear equality constraint..Just click on the figure to enlarge the figure.

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Improvement of Maximum Load-ability of Power system by FACTS devices:Part 3

In the previous posts the Maximum load-ability problem without FACTS devices was discussed and modeled as an optimization problem.The problem has to modified to include the effect of FACTS devices. A brief introduction is given on the different FACTS devices.

A flexible alternating current transmission system (FACTS)

It is a system composed of static equipment used for the AC transmission of electrical energy. It is meant to enhance controllability and increase power transfer capability of the network. It is generally a power electronics-based system. There are two types of FACTS devices series and shuunt connected devies.

Series compensation

In series compensation, the FACTS is connected in series with the power system. It works as a controllable voltage source. Series inductance occurs in long transmission lines, and when a large current flow causes a large voltage drop. To compensate, series capacitors are connected.

Shunt compensation

In shunt compensation, power system is connected in shunt (parallel) with the FACTS. It works as a controllable current source. Shunt compensation is of two types:

Shunt capacitive compensation

This method is used to improve the power factor. Whenever an inductive load is connected to the transmission line, power factor lags because of lagging load current. To compensate, a shunt capacitor is connected which draws current leading the source voltage. The net result is improvement in power factor.

Shunt inductive compensation

This method is used either when charging the transmission line, or, when there is very low load at the receiving end. Due to very low, or no load – very low current flows through the transmission line. Shunt capacitance in the transmission line causes voltage amplification (Ferranti Effect). The receiving end voltage may become double the sending end voltage (generally in case of very long transmission lines). To compensate, shunt inductors are connected across the transmission line.

Series compensation devices

• Static synchronous series compensator (SSSC)
• Thyristor-controlled series capacitor (TCSC): a series capacitor bank is shunted by a thyristor-controlled reactor
• Thyristor-controlled series reactor (TCSR): a series reactor bank is shunted by a thyristor-controlled reactor
• Thyristor-switched series capacitor (TSSC): a series capacitor bank is shunted by a thyristor-switched reactor
• Thyristor-switched series reactor (TSSR): a series reactor bank is shunted by a thyristor-switched reactor

Shunt compensation devices

Static synchronous compensator (STATCOM); previously known as a static condenser (STATCON)

• Static VAR compensator (SVC).