electrical engineering end of semester project

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Final Project EE-431

Introduction

This project aims to determine your ability to apply the concepts and methods discussed in class

for a power system design problem. You can develop your own software in your language of

choice, and/or use the software tools utilized in the class (i.e. MATLAB) or you can follow the

procedure by hand calculations.

Objective

● To carry out the design of a power transmission system that runs through urban service

territories.

● To apply your knowledge from class in computing parameters for component models,

perform steady-state analysis.

● To build software scripts and use different software tools towards your design.

● To document your results, calculations, and source code (if applicable) in a report.

Design Project Statement and Data

Design Problem Statement

The design problem consists in expanding a transmission system to serve a 4-bus power system

shown in the map in Fig. 1 and to also determine if the existing transmission system needs to be

upgraded to handle an additional growth (40MW) in the existing load connected to the Bus 3. This

requires to redesign and build new transmission infrastructure, and to perform power flow analysis

studies using Newton-Raphson method.

Transmission System

The transmission system in Figure 1, below, contains both 161 kV transmission lines and

substations that go through urban service territories. The load at each of the buses is provided in

Table 1, and the parameters of the existing lines are shown in Table 2.

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Figure 1. One-line Diagram of the 4-Bus Power System

Substations Buses and Loads

The buses shown in the diagram correspond not only to electrical buses, but to substations:

Buses 1-2 are substations at power sources (i.e. generation plants) at 161 kV.

○ Each power source is rated at 100 MVA, and should be represented by their

equivalent current sources with their reactances in per unit on a 100 MVA-

base as shown below.

Bus # Bus Name Reactance Capacity

1 Generator j0.25 100 MVA

2 Generator j0.20 100 MVA

● Buses 3-4 are urban load substations, assume a voltage magnitude of 1.0 per unit at

buses 3 and 4.

Bus # Load (MW) Load (MVAr)

3 100 25

4 150 50

Table 1. Loads at different buses

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Transmission Lines

Parameters for Existing Lines

The parameters of the existing transmission lines representing by π model where series

reactances and shunt reactances expressed in per unit on a 100MVA base are provided in Table

2, below.

Bus # Bus # R (p.u) XL (p.u) XC (p.u)

1 2 0 0.25 -4

1 3 0 0.1 -4

1 4 0 0.4 -4

2 4 0 0.16 -4

3 4 0 0.2 -4

Table 2. Transmission Line Parameters

Design Phases Overview

The project is structured so that you conduct this project in 4 different phases, as follows:

1. In the first phase of the design, the only requirement is to convert the loads, generation

units, and transmission lines to the corresponding impedance parameters.

This phase consists of transforming all the data to per unit quantities, if not already in per

unit.

The remaining step of the design requires to consider the location of the equivalent current

source of power generators along with the given reactance per each generator.

2. The second phase consists in using the per-unit data of all system components to compute

both Ybus and Zbus.

3. The third phase consists in a power flow study of the system under different load growth

scenarios.

4. The final phase is to prepare a report describing obtained results based on this analysis.

Phase 1

In this phase you are asked to draw the existing system in per unit with all values making design

to serve the load and generation subject to the specifications and design tasks as described

below.

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Design Tasks

a. Calculate per unit values of impedances of all the transmission lines using a suitable

software. You can make your own hand calculation, or use MATLAB. The resistance of

lines is ignored. The line reactances at rated voltage is provided in Table 2.

b. Each power source (generator) should be connected to the Bus 1 and Bus 2 with specified

reactance above.

c. Calculate all the per unit values of the loads on a 100 MVA base, with a voltage base of

161 kV (1 p.u.) as appropriate.

Create a table with all the parameters of the system in per unit.

Phase 2

This phase is a continuation of Phase 1 consists of building the Ybus and Zbus matrices.

Design Tasks

For the parameters determined in Phase 1, perform the following calculations.

d. Use the MATLAB Command other code to compute Ybus and Zbus. You can proceed

with hand calculations if you wish.

e. Compute the bus admittance matrix, Ybus and bus impedance matrix, Zbus with all the

parameters expressed in per unit on the common system base of 100 MVA.

Phase 3

This phase consists in performing different power flow studies for the system set up in the previous

phases. You will consider the following case studies:

● Case 1: Base case system with base loads as specified in Table 1.

● Case 2: Modified system with adding a 40 MW “Data Center” load connected to Bus 3.

Design Tasks

f. Perform power flow analysis based on Newton-Raphson method on Case 1 and verify the

design requirements listed below.

g. Modify the 4-bus power system to supply the new 40 MW load connected to Bus 3 and

repeat Newton-Raphson power flow analysis.

h. Summarize graphically (one plot for each Cases 1 and 2) the power flow results from the

two cases analyzed above, show the bus voltage magnitude and angle, active and

reactive powers.

i. Compare the MVA in the loads, the MVA used in the lines, and the MVA from the

generators in each case.

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Design Criteria and Specifications

Criteria

When carrying out the design tasks above, you must meet the following design criteria:

● R1. Satisfactory system operation: all voltages should be in the range from 0.95 to 1.05

pu, with no overloaded lines.

● R2. Loads: from the power flow results, determine the total load in the system, the losses

across lines and total generation.

Phase 4

This final phase is about documentation of your obtained results considering the below guidelines:

A deadline for report submission is on December 11th, 2020 by 5:00 pm.

Report Requirements and Structure

Your report should be structured as described below.

1. Executive Summary: a maximum 1-2 page summary that includes the main information

of your project.

This should contain everything that I need to know to grade you without having to read

the whole report. Make this a “self contained” document.

Your summary should include at least the following:

a. Summarize the changes required (for example the capacity of transmission lines,

choosing lower or high capacity of cables, etc.) at each case in Phase 3 using a

table.

b. Contrast the analysis methods and results of Phase 3.

c. Use a minimum of 1 figure and a maximum of 2 figures to highlight your most

important finding.

2. Report Structure:

a. Title page

b. Table of contents.

c. System Description

i. A one-line diagram of the system showing the generators, bus, line, and

load connections. Explain your suggestion to achieve a better system

operation if you think there is a need for modifications by adding new 40MW

loads at Bus 3.

ii. Specifications of each line in the system: connection between buses,

voltage, series impedance and shunt capacitance reactance, and MVA and

current ratings.

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d. Design Summary

i. Provide a summary of results from all other design phases here. You

should aim to summarize each phase with a short paragraph and preferably

through 1 or 2 figures. You might prefer that all other details (calculations,

tables, figures) for each design phase to be included in a dedicated

Appendix.

ii. Design Analysis:

1. Compare the analysis results of Case 1 and Case 2 in Phase 3.

2. Use a minimum of 1 figure and a maximum of 2 figures to highlight

your most important finding.

iii. Design Tools (if using software):

1. Software Documentation: Briefly explain, through a

flowchart/discussion, how you were able to do the analysis required

through different software routines or by using different

functions/software and reading data.

e. Conclusions: briefly discuss your findings. Keep this short, 1-2 paragraphs, 1

figure, and highlight your most important finding.

3. Other:

a. Number and title all figures.

b. Number and title all tables.

c. Document all changes made from the base case design in a dedicated Appendix,

be organized!

Final Remarks

Do your own work!

● This project serves as a way to measure your ability to apply the intended learning

outcomes. You must make sure during the course that you will be able to do the work

described here, and thus, you must do all the homework assignments to be able to have

the skills you need.

● This project may have not a unique solution, so there is likely possible way that you

can have the different solution as another student.