WindMil 101 - Engineering Analysis Software - Bill Kersting

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WindMil 101 Bill Kersting

http://www.milsoft.com/



Distribution System Modeling and Analysi

•

Primary purposes of the first two editions.

–

Define terms used in defining “loads”. – Present approximate methods for voltage drop and power lo

– Develop models

•

OH and UG lines

•

Step type voltage regulators

•

Some three-phase transformer connection models, including center t

•

Introduction to the Ladder Technique for power-flow analysis



Third Edition

• Complete models for all standard three-phase transformer connections with and without ce

transformers.

•

Add the use of WindMil. – Student version downloaded.

–

Homework problems that compare models developed by hand and the same model d

WindMil.

– Major assignment at the end of the book to allow the students to run power-flow ana

test feeder and fix any problems.

• Node voltages not within ANSI requirements.

–

Apply step voltage regulators.

– Install shunt capacitors.

• Add single-phase center tapped transformers with secondary to test feeder.

• A tutorial has been developed for the students to use in developing an understanding how

models are applied and used in WindMil.



Problem 4.1 – Overhead Three-Phase Line



Set Spacing Matrix



Compute Primitive Impedance Matrix



Kron Reduction



Display Homework 4.1 and 5.1 Results



System 1WindMil Assignment: 12.47 kV line-to-line source. The “Bus Voltage” should be se

to 120 Volts. Z+ = 8.4 + j21.4 Ohms, Z0 19.0 + j44.9 Ohms.Connect to a node and call it Node 1

A 5000 ft. long overhead three distribution line as defined inProblem 4.1 Call this line OH-1.

Connect a node to the end of the line and call it Node 2

A wye connected unbalanced three-phase load is connected

Node 2 and is modeled as constant PQ load with values of:Phase a-g: 1000 kVA, Power factor = 90 % lagging

Phase b-g: 800 kVA, Power factor = 85 % laggingPhase c-g: 1200 kVA, Power factor = 95 % lagging

Determine the voltages on a 120 volt base at Node 2 and thecurrent flowing on the OH-1 line



Start WindMil and Click File/New



Click on EQDB/Use Different Equipment



Define Location of Data Base



Click Preferences/System Preferences



Click on Modeling and Select 50 C



Click on View/Display Options



Click on General and Select One Line Dia

and Schematic Symbols



Define Size of Symbols



Start System 1 by Selecting Add Source



Click on the source icon and then on navig



Click on New and Input Source Data



Define Source Voltages



Connect Node 1 to the Source



Connect an OH Line to Node 1



Input Necessary Data as Shown



Select the Desired Conductor from the AC



Define Line Construction Spacings



Give the Construction a Name



Select Conductor Distances

Input xy Coordinates for Phase and Neutral Con



Input xy Coordinates for Phase and Neutral Con

don

t Click on Assume Full Transposition



Define the Phasing



Connect Node 2 to the End of the OH Line



Click on Node 2 to Start Defining the Load



Click New and type in equipment name



Set the Y-PQ load as shown



Input the Load kW and kvar Values

Before Running Select Voltage Drop/Settings an



Before Running Select Voltage Drop/Settings an

Click Assume Transposition. Click apply and ru



Use Calculated Data Box to Display Node

N d 2 V l 120 V l B



Node 2 Voltages on 120 Volt Base

C U D fi d b



Create a User Defined box

Cli k N d fi d



Click on New to create a new user defined

Name the template. Browse though the fields to select Thru Amps. D



Name the template. Browse though the fields to select Thru Amps. D

Amps over to the Selected Variables box.

Click on Thru Amps. In Display in select Polar, In Unit



p p y ,

Amps or Volts. Click on OK.

Displayed will be the template name and the current valu



p y p

OH line. Click OK to return to the diagram.

D t B f li t di l d



Data Box for line currents displayed

Double click on OH 1 and then editor. Click on Impeda



p

display the Z and Y matrices for the line.

Summary



Summary

System 2



System 2

Problem 4 3



Problem 4.3

System 2



System 2

Results for System 2



Results for System 2

System 3



System 3

Concentric Neutral Data



Concentric Neutral Data

Create the Concentric Neutral Cable



Create the Concentric Neutral Cable

Define Construction for Two Phase UG



Define Construction for Two Phase UG

Connect Node 4 to the End of the UG Line



Connect Node 4 to the End of the UG Line

Define the Constant Current Delta Load



Define the Constant Current Delta Load

Display Results



Display Results

Node 4 Line-to-Line Voltage



Node 4 Line to Line Voltage

System 4



y

The regulator needs to be placed between the source and Node 1. To do thi

x as shown with line 1 below. Then click on the regulator. This sets up the



of the regulator after the source.

Click on the source and hold the left key down and drag down and to the rig

the regulator between the source and Node 1.



the regulator between the source and Node 1.

Double click on the regulator. Change the name to Reg 1. Also rotate the p

ACB is the phasing.



ACB is the phasing.

Set the Voltage Level to 122 Volts. Select 1-Ph with all phases the same”

.

Regulator Size Definition box.



egulato Size efinition box.

Click on New and type in the name for the single-phase regulator.



Type in the CT Rating, Amps Rating, % Boost and the Total Bandwidth. C

Notice that the 7200 Volt, 1 phase regulator is in the Regulator Equipment



, p g g q p

Click in the box shown and click on Set Regulation. This is the first step in

WindMil compute the required R and X settings for the compensator.



p q g f p

After selecting Set Regulation”

click on the regulator and then click the A

on the menu bar and then click on Analysis Manager.



The window will appear as shown below. If the Regulator Name is blank c All Regulators”

and Reg 1 will be shown. Click on the arrow in the Load C

display possible Load Center locations. Select Node 2. Click on Regulator



Settings.

After clicking on Regulator Limit Settings verify that the Most Desirable Vo122 volts and Unbalanced ” is clicked. Also make sure that the R and X m

settings are not zero Click on LDC Rules



settings are not zero. Click on LDC Rules.

After clicking on LDC Rules this window appears. Click on Use Line DroCompensation” and the button Hold Load Center at Most Desirable Volta

Apply & Run



Apply & Run.

WindMil has computed the R and X settings that should hold the voltages a

between 121 and 123 volts.



Select Voltage Drop”

and then the Analysis/Analysis Manager. Make sur

Regulator is set to Step” . Click on Apply & Run.



The Voltage Drop analysis has been performed. To display the regulator tadefined box needs to be created. Click on Reg 1 the User-defined Data Box

Define.



Define.

Click on New, type in the Template Name. Scroll down the list until Regu

Equipment ” is found. Drag this over to the Selected Variables box. Click o



To specify the tap settings click on Edit Template.



Scroll down the Field list until Regulator Num Steps is found. Drag over fo

and C. Change the name of the user defined box to Reg Taps” . Click on



After running voltage drop select Reg 1 to display the user defined data boxis also good to use the Calculated Data Box at Node 2 to demonstrate that t

are within the range 121 to 123 volts.



g

To compute the R and X settings by hand it is necessary to run Voltage Drobalanced run with lines transposed. Open Analysis Options and click on A

Transposition and click None on Regulators.



Click on Analysis Settings and click the Balanced button. Click App



Use the user defined boxes to display the actual voltages at Nodes 1 and 2 acurrent in the line. Note that the voltages and currents are balanced so the

to only be calculated for phase a.



Compensator Settings



• WindMil using Set Regulation: Z = 1.6 + j5.1 Volts

• Mathcad computation: Z: 1.5 + j4.7 Volts

•

The two values are very close. WindMil uses a slightly differencompute the required compensator R and X settings.

Summary Systems 2,3 and 4



• A single-phase OH line was added to System 1 to created Syste

• An underground concentric neutral cable was created and used

two phase UG line to add to System 2 to create System 3.• The steps to install a three-phase Y-Y connected step regulator

demonstrated. This was added to System 3 to created System 4

• The necessary steps to have WindMil compute the needed com

and X settings was demonstrated.

•

WindMil was run with the regulators holding the Node 2 voltagthe desired voltage limits.

• The steps to compute the R and X compensator settings were d

System 5 Assignment. As before, save System 4 as System 5.

Wi dMil A i t



• WindMil Assignment

• Use System 4 to build this new System 5. A 5,000 kVA delta-gwye substation transformer is to be connected between the sour

1. The voltages for the transformer are 115 kV delta to 12.47 kwye. The impedance of this transformer is 8.06 % with an X/R installing this substation transformer be sure to modify the souris 115,000 V rather than the 12.47 V. Follow the steps in the UManual on how to install the substation transformer.

• When the transformer has been connected run Voltage Drop.

•

What are the node voltages at Node 2?• What taps has the regulator gone to?

• Why did the taps increase when the transformer was added to th

System 5 requires that the substation transformer be connected between thethe regulator. In order to make room for this addition a feature in WindMi

demonstrated. Click on the black arrow in the toolbar and then click and h

and drag it to the right



and drag it to the right.

Moving Node 1 will produce this display. Repeat the process to move Reg 1

right.



Moving Reg 1 leaves room to install the substation transformer and an anode. The names on the elements can be moved by clicking on the nam

dragging it to the desired position.



Follow the same procedures as before to add the substation transformer. C

between the transformer and the regulator.



Double click on the transformer symbol and select D-Y Grd as the connecti115000 for the Rated Input Voltage and 12470 for the Rated and Nominal

Click on the box next to Phase A to define the transformer.



Click on New and type in the name of the transformer.



Select Three Phase Transformer ”

from the drop down list. Type in the im

kVA values.



Double click on the source symbol in order to create the required 115,000 k

Click on the Impedance Code box.



Click on New and type in the Name of new equipment. Click OK.



Even though the 115 kV system equivalent impedances are not needed for t

drop studies they can be entered at this time and will be used in short circui



Click on Impedance Code Max and select the 115,000 kV source. Change tthe source. Type in the 115000 as the nominal L-L voltage. The computer

the Nominal L-G voltage. Click Close and run Voltage Drop.



The results show that the Node 2 voltages are still within the limits of the 12voltages. Note that the regulator taps have changed after the substation tra

added.



Assignment 6. As before, save System 5 as System 6. Note in the assignmethe impedance of the 15 kVA transformer has been changed to a more reali

than that given in the book.



Click on the transformer symbol and connect to Node 2. Double click on thconnected to Node 2. Click on the box for Phase A of Impedance Definitio



Click on New and type in the name of the transformer.



Select Single Phase Transformer from the drop down list. Type in the imperating of the transformer. Click OK.



Change the name of the transformer. Type in 240 volts as the rated and novoltages. Click Close.



Connect Node 5 to the Mt. Transformer.



Connect a motor to Node 5 by clicking on the motor symbol in the menu baclick on Node 5 and drag out a little ways.



Double click on the motor. Type in Total Motor HP to be 25. Click on Ad Model ” . Change the name and input the Total Motor HP. Type in the Rat

and click on the box next to Motor Conductor.



Click on New and name the motor. Click OK.



Set the current capacity to 60 amps. Click the Motor Impedance box, click button and then input the stator, rotor and shunt impedances. Click OK.



Click on Fixed Slip. Input the specified slip and select Running from the Mdown list.



Run voltage drop. The results are shown below. The kW and kvar flow ondisplayed using the PQ Flow user defined data box.



Summary

• It was shown how to “move” elements on the circuit.



• A substation delta-grounded wye transformer was connected be

source and the voltage regulator.

• A distribution ungrounded wye-delta three phase balanced tran

bank was installed.

• A three-phase induction motor was installed using the advanced

a fixed value of slip. The Load kW is computed.

–

If a fixed Load kW is specified, the operating slip is compu – If you input a negative slip, the induction machine becomes

generator.

System 7 All of the necessary data is given

Source

Node



bc

c a

c

a

6

2

3

410 11

12

13

5

7

8

9

a

a

b

c

a b c4'

3'

1

a

ab

c

Assignment 7



Assignment 8



Assignment 8 (cont.)



Wrap Up

•

Step-by-step for the creation of simple systems.

http://www.milsoft.com/contact-us



•

Demonstrate methods to display results.

•

Add a step voltage regulator bank and demonstrate Wand hand method for computing the R and X settings

•

Add a 115kV source system with substation transform

•

Finally

–

Create a 13 node system. –

Solve a variety of problems.

http://www.milsoft.com/contact-us

WindMil 101 - Engineering Analysis Software - Bill Kersting

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