Phần 23 KHÓA ĐÀO TẠO TÍNH TOÁN ỔN ĐỊNH VÀ ỨNG DỤNG TRÊN DỤNG PHẦN MỀM PSSE CHO KỸ SƯ HỆ THỐNG ĐIỆN (Kịch bản nghiên cứu theo tiêu chuẩn IEEE trên Phần mềm PSSE)

KHÓA ĐÀO TẠO TÍNH TOÁN ỔN ĐỊNH VÀ HƯỚNG DẪN SỬ DỤNG PHẦN MỀM PSSE CHO KỸ SƯ HỆ THỐNG ĐIỆN (Kịch bản nghiên cứu theo tiêu chuẩn IEEE trên Phần mềm PSSE): • Saved Case Buildup. • Creating a Single Line Diagram. • Load Flow Analysis. • N1 Contingency Analysis. • ShortCircuit Analysis.

Day 12 - Case Study – IEEE 24 Bus Test System

PART 1

July 19, 2013 Prepared by: Frida Ceja-Gomez

• Saved Case Build-up

Creating a Single Line Diagram

• Creating a Single Line Diagram

• N-1 Contingency Analysis

• Short-Circuit Analysis

IEEE 24 – SAVED CASE

IEEE 24 – SAVED CASE

BUILD-UP

• The purpose of this exercise is to build a test case from p p

scratch on PSS®E and then perform all the types of

analysis covered during Part A of this course

Reliability Test System 1996

select Network Case

• Leave the MVA Base as 100 and the frequency as 60Hz

• We will input the transformer ratings in MVA units

For non transformer branches the current will be expressed as

• For non-transformer branches the current will be expressed as

MVA

• The heading lines are just to provide some information about g j p

• Use the following g

bus data as an

input

of each bus type

eBook for You

• Our test system has 10 generators y g

generator

Enter RTran = 0 015pu and Xtran = 0 125pu for all machines

• Enter RTran = 0.015pu and Xtran = 0.125pu for all machines

• These values are the step-up transformer impedance in pu on Mbase

• Leave Gentap = 1, which is the transformer off-nominal turns ratio in pu on

the system base

• PSS®E assumes the GSU transformer has a delta-wye configuration as PSS®E assumes the GSU transformer has a delta wye configuration, as

• Add the following loads to their respective buses g p

Th IEEE 24 h h fi 230 138kV

transformers shown below

configuration on both sides

• We will add an on-load tap changer to the two-winding

transformers

• The information for the OLTC of our 5 two-winding

transformers is shown below:

• Controlled Bus: LV side

• The system only has one fixed shunt

capacitor

IEEE 24 – CREATING A SINGLE

IEEE 24 – CREATING A SINGLE

LINE DIAGRAM

• Go to the File

menu, click on

New and select

Diagram

Draw option and

• Now let us grow g

• Finally, grow

Bus 22 one

level

• Now that we

have all the

have all the

• In the Diagram In the Diagram

• In the Diagram tool In the Diagram tool

menu, use the Title

and Lgnd buttons

to add information

to the diagram

color and size can

• Also in the Diagram g

tool menu, the

can add all the bus

can add all the bus

• This is how the

IEEE 24 – LOAD FLOW

IEEE 24 – LOAD FLOW

ANALYSIS

been built, run the load flow analysis

• Verify the output bar to make sure that the simulation

converged

• Why is there a star (*) to the right of the swing bus QGEN?

set flags for limit violations in the single line diagram

• Right-click on the diagram and select Diagram Annotation,

where you can enable the option to check line loadings and

voltage limits

• Under the Power Flow, Reports, Limit checking reports

menu select the Voltage limits option

• Under the Power Flow,

Reports, Limit checking

reports menu select the

reports menu, select the

Branches option

• Reliability criteria may vary depending on the utility

contingencies shall typically fulfill the following

conditions

• There shall not be any overloads present

• There shall not be any buses with voltages higher

than 1.05 pu

• There shall not be any buses with voltages lower than

0.95 pu

that the above criteria is satisfied

• It will be necessary to modify the transformers

ratings

• Note that it is not necessary to modify the y y

resistance/reactance since these parameters

were input with respect to the winding MVA

base which has not been modified

• To address the low voltage at buses 3 and 24, it

will be necessary to add a reactive

• To address the low voltage at buses 4, 5, 6, 8, 9,

10, 11 and 14, another reactive compensation

device will be needed

• Place a fixed shunt capacitor of 115 MVAR at

bus 10

• Once these changes have been made, run the

load flow simulation again

• Although the overloads and low voltage issues have been g g

resolved, it can be seen that the swing machine is still

running above its reactive power limit

• To correct this problem, we need to increase the scheduled voltage at

nearby PV buses to encourage other machines to increase their reactive

power output

• Set the scheduled voltage at bus 23 to 1.03pu and re-run the simulation g p

S N 1 t k l it ti t

• Some N-1 cases may take several iterations to converge,

so it is useful to increase the number of allowed iterations

• Write a subsystem file defining the whole

system as well a subsystem for each area

• Write a monitoring file to monitor

• Write a contingency file to trip each of

branches in the system, one at a time

• Go to AC contingency solution (ACCC) and

build the distribution factor data file

• Verify the output bar for any problems with

the distribution factor file

• Note that one of the contingencies isolates a

bus

• Name the contingency solution output file

• Name the contingency solution output file

and solve

• How many contingencies cause line

• What lines should be upgraded to avoid

major overloads?

• Where should more lines be built to

prevent excessive overloads?

• Is it necessary to add more reactive

power compensation to keep the

voltage within acceptable limits? If so,

where?

• When it is not possible to add or

upgrade lines, it is necessary to

develop operational measures to

develop operational measures to

protect lines and other equipment from

high overloads

• What remedial action schemes would

you implement for the safe operation of

this system?

• When we built the IEEE 24 Test System,

there was no input data for the zero p

sequence parameters

• Although it is always preferable to input Although it is always preferable to input

true system data, as power system

planners, we can make some

assumptions when the negative and

assumptions when the negative and

zero sequence parameters are not

available

• As discussed in the Introduction to PSS®E training and

with the aid of an Excel spreadsheet, generate these

parameters using the following assumptions:

• Negative-sequence impedance is equal to

positive-sequence impedance for all equipment

• Zero-sequence impedance of generators is equal to ¼

of positive-sequence impedance

• Zero-sequence impedance of transformer is equal to

positive-sequence impedance

• Zero-sequence impedance of lines is equal to three

• Zero-sequence impedance of lines is equal to three

times the positive-sequence impedance (B0 = ½ B1)

• This activity allows to perform

short-circuit analysis on our test system by y y y

applying a fault at the specified bus(es)

• Before we begin, it will be necessary to Before we begin, it will be necessary to

modify some program settings so that

our short-circuit analysis results are

more meaningful

• Go to the Misc menu,

and select Change

Program Settings

• Change the

short-circuit output to

Physical and the

Physical and the

magnitude and angle

• Go to the Fault menu

and select the ASCC

and select the ASCC

option

• Set the pre-fault

diti th li conditions as the linear

power flow

• Choose to analyze

three-phase and

line-to-ground faults

• Select the output as Select the output as

Fault current summary

table

• Select all buses and

• Select all buses and

click Go

QUESTIONS?

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