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Electronic and Computer Engineering

School of Engineering and Design

Assessed Coursework 2008/9

MSc Course: Sustainable Electrical Power

Level: 5

Module Code: EE5523

Module Name: Sustainable Electrical Power Workshop

Laboratory Worksheet Code: 5523_5522_1

Title of Laboratory Worksheet:Optimal Power Flow Analysis & Loss Minimisation using PowerWorld

Set By: Dr Gary TaylorChecked By: Dr Gary TaylorContribution to Module Mark: 6%Total Expected Study Time: 6 hours

Distribution (to students) Date: 6thFebruary 2009

Submission Deadline: FT 20 February & PT 27 February 2009

1.Background/Introduction

Optimal Power Flow (OPF) analysis software is now widely deployed in order to optimisethe operation of electrical power systems. PowerWorld is a widely used commercialsoftware package with a state-of-the-art Graphical User Interface (GUI). PowerWorldenables the user to perform OPF studies for a range of power system problems includingeconomic dispatch and loss minimisation.

2.Learning OutcomesAfter completing this practical work you will

Know how to perform detailed OPF & loss minimisation analysisusing PowerWorld

Be able to execute and analyse simple Economic Dispatch (ED)and loss minimisation case studies in PowerWorld

Be familiar with the OPF, ED and loss minimisation functionalityof PowerWorld

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3.Tasks / QuestionsIt is important to note that you are required to prepare a detailed laboratory report for

this assignment. Your report should include detailed descriptions of all the main tasksperformed, results obtained, conclusions and relevant screen captures when possible.

To copy the window or screen contents

To make a copy of the active window, press ALT+PRINT SCREEN.

To copy the entire screen as it appears on your monitor, press PRINT SCREEN.

Note

To paste the image into a document, click the Edit menu in the documentwindow, and then click Paste.

Step 1

In this laboratory exercise you will be using an educational version of the PowerWorldSimulator (PW Simulator). In order to run the software you can clickstart / All Programs / PowerWorld / Simulator

In order to perform an OPF study on a power system the user is required to provide thesoftware with a model of the power system with appropriate data. With PW simulator theuser can either build a new model by creating a new case or the user can start from anexisting case. At this stage you should ensure that the following folder is accessible onyour PC;Example 11

In this laboratory exercise you will start with an existing case (Example11_8, Chapter

11, Glover & Sharma). In order to open an existing case clickFile / Open CaseYou may select the case Example11_8, that can be found in the folder Chapter 11.There are usually two files associated with a PW Simulator case; the binary file and the.pwd file. Both files are normally required to open an existing case.

The following model should be displayed in the PW Simulator;

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The power system that is displayed in the figure above is displayed as a one-line

diagram. This PS Simulator case study above uses a five-bus, three-generator case todemonstrate the interaction between economic dispatch and the transmission network. It

is important to note that the above case includes network losses.

Step 2

What are the impedances of each line in the above case? What is the R/X ratio for eachline? What is the economic dispatch solution with a load scalar of 1.00?

Step 3

The current value of each generators loss sensitivity dPL/dPi is displayed immediatelybelow the MW output field of each generator. Using these values for each generatorverify using the calculation methods in the lectures that the solution is optimal.

Step 4In addition to solving the power flow equations PowerWorld can also solve the economicdispatch problem and calculate the losses.

This option is controlled by selecting Case Information, AreasThe AGC status field can be toggled to ED in order to select economic dispatch.

Use Simulation, Play

In order to see how changing the load impacts on the economic despatch and power flowsolutions click on the up/down arrows on the Load Scalar field.

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Determine the MW losses for the maximum load that can be supplied withoutoverloading any transmission line with generators dispatched using economic despatch.

Step 5With a load scalar of 1.0 resolve the above case systematically in order to determine thegeneration dispatch that minimises the losses. Hint: Manually vary the generation at

buses 2 and 4 until their loss sensitivity values are zero.

Compare the operating cost between this solution and the original ED solution andcomment upon the different solutions.Repeat the problem again with a load scalar of 1.2.

Include a discussion of the above power system in your report. Your discussion shouldinclude details concerning OPF, ED and loss minimisation using PowerWorld.

4.Submission ProcessSED PG TPO (Michael Sterling Building ML056)

5.Late Submission PenaltyStandard penalties will be applied.