optimization of power sytem

OUR EXPERIENCE, CONCEPTS AND UNDERSTANDINGS

Optimization of Power System Operation

Introduction

Electricity generating companies and power systems have the problem of deciding how best to meet the varying demand for electricity, which has a daily and weekly cycle.

This study essentially deals with the method of operating Electrical generating sets of different type, to get the economic power from them.

The terms ‘Unit Commitment’, ‘Economic Dispatch’ and ‘Incremental Cost’ are widely used in this study discipline.

The steps for optimization

Long Term System PlanningHourly and Monthly decisions -- Unit CommitmentInstantaneous Dispatch decisions -- Economic DispatchShort term system operation -- Load Flow Model

Economic Dispatch- Covered Earlier

Energy Policy Act defines “Economic Dispatch” to mean “the operation of generation facilities to produce energy at the lowest cost to reliably serve consumers, recognizing any operational limits of generation and transmission facilities.” [EPAct 2005, Sec. 1234 (b)]

Actually, For Power System Economic Operation, the installed generating capacity should be

greater than the load at any specific moment

This topic is covered in earlier presentation

Unit Commitment

The electrical unit commitment problem is the problem of deciding which electricity generation units should be running in each period so as to satisfy a predictably varying demand for electricity.

The problem is interesting because in a typical electrical system there are a variety of units available for generating electricity, and each has its own characteristics.

Unit Commitment- The Constraints

UC problem is a complex optimization problem which requires rigorous enumeration of all feasible combination of the generation units.

The Problem typically involve technological and economic constraints. Spinning Reserve Thermal Unit Constraints

Minimum Up Time Minimum Down Time Start-Up Cost Shut-Down cost

Hydro Constraints Must Run Fuel Constraint

Unit Commitment- Solution Methods

Most common techniques are,

Priority-list Schemes-simplest method but enormous computational time-based on shut down rule-creates a priority list of units by an exhaustive

enumeration

Heuristic Methods-Uses pre-calculated priority list and incorporate all the

operating constraints heuristically.

Mixed Integer Programming

UC - Solution Methods (Continued.)

Dynamic Programming-advantage over PLS is reduction in the

dimensionality of the problem-systematically evaluates a large number of

possible decisions in a multi-step problem Lagrange Relaxation

-based on dual optimization approach

Dynamic Programming-Illustrated

The objective is to find minimum cost from A-N.

K=1,2…5= Hour

At the end of each hour, a decision is taken to enter on which state.

Advances in Unit Commitment Problem

Genetic Algorithm

-The genetic based UC program starts with a random initial population (at T=0) at it computes the fitness of each individual.

-Advanced level of GA is used like Fast Messy Genetic Algorithm (FMGA)

Various algorithms to UC Problem

Ant Colony System ( S. P. Simon, N. P. Padhy and R. S. Anand)

- foraging behavior of the real ants for finding its food from its start (nest) to its destination (food) is simulated to obtain the optimum solution.

A Practical Software: e-terracommit

A Practical Software

Power Generation Machines

GE 9E GAS TURBINE

Rolls-Royce BV16 HFO Engine

Power Generation Machines

Inside a power plant

Thank you

Muhammad Samiul Alamm.samiul.alam@gmail.comID 11161004, MSc(EEE)BRAC University, Bangladesh