512 manual

ENEE512

--------------------------------------------------------------------------------------------------------

1

Experiment#1

Introduction to Siemens PLCs

Object: To introduce the students to Siemens PLCs programming and to step 7

software tools.

To be familiar with Siemens PLCs timers and counters.

To learn how to program using Statement List programming.

Pre lab:

Study the theory behind the Siemens PLCs

Equipments Required:

SIMATIC C7-621, SIMATIC S5-100U, PG 605U Programmer, STEP 7 programming

software.

Procedure:

Create new step 7 software project using SIMATIC Manager program.

Select the C7-621 hardware from SIMATIC 300>>C7.

From the Blocks folder, open the organization block OB1.

[A]: Programming with Symbols

Absolute Addresses

Every input and output has an absolute address predefined by the hardware

configuration. This address is specified directly; that is, absolutely. The absolute

address can be replaced by any symbolic name you choose.

Symbolic Programming

In the symbol table, you assign a symbolic name and the data type to all the absolute

addresses which you will address later on in your program; for example, for input I

0.1 the symbolic name Key 1. These names apply to all parts of the program and are

known as global variables.

Open the symbol table by selecting (Options >> Symbol table) from the menu

bar, or by pressing (Ctrl+Alt+T) on the keyboard.

ENEE512

--------------------------------------------------------------------------------------------------------

2

Fill the symbol table as follows:

Table 1.1

Save the symbol table and Exit from the symbol editor.

To change from absolute addressing to symbolic addressing, select the menu

item (View>>Display>>Symbolic Representation) or press (Ctrl+Q) on the

keyboard.

Note: We refer to the “result of logic operation” By RLO.

[B]: Set & Reset Coil

The Set Coil instruction is executed only if the RLO = 1. If the RLO = 1, this

instruction sets its specified address to 1. If the RLO = 0, the instruction has no effect

on the specified address. The address remains unchanged.

The Reset Coil instruction is executed only if the RLO = 1. If the RLO = 1, this

instruction resets its specified address to 0. If the RLO = 0, the instruction has no

effect on its specified address. The address remains unchanged.

Q1) What is the difference between output coil and set coil instructions?

Create the following ladder diagram in your project, and download it to the PLC

SIMATIC C7-621, then test its operation.

Figure 1.1

ENEE512

--------------------------------------------------------------------------------------------------------

3

Create the same program on SIMATIC S5-100U PLC using statement list

programming as follows. Then test its operation.

A I 0.0 AN I 0.1 S Q 1.0 O I 0.2 O I 0.3 R Q 1.0

[C]: PLC Timers Timers have an area reserved for them in the memory of your CPU. This memory area

reserves one 16-bit word for each timer address. The ladder logic instruction set

supports 256 timers.

(SD) (On Delay Timer Coil) starts the specified timer with the <time value> if there

is a positive edge on the RLO state. The signal state of the timer is "1" when the <time

value> has elapsed without error and the RLO is still "1". When the RLO changes

from "1" to "0" while the timer is running, the timer is reset. In this case, a scan for

"1" always produces the result "0."

Open the timer's folder in the program elements, and check out the

different types of timers. Mark each timer and press F1 to display the

help to that timer.

Q2) From the help, explain the operation of the SP timer.

Create the ladder diagram in figure 1.2, and then test its operation

using PLC SIMATIC C7-621.

ENEE512

--------------------------------------------------------------------------------------------------------

4

Figure 1.2

Create the same program on SIMATIC S5-100U PLC using statement

list programming as follows. Then test its operation.

A I 0.0

L KT 5.2

SR T 1

A T 1

= Q 1.0

A T 1

L KT 7.2

SR T 2

A I 0.1

R T 2

A T 2

= Q 1.1

A I 0.1

R T 1

[D]: PLC Counters Counters have an area reserved for them in the memory of your CPU. This memory

area reserves one 16-bit word for each counter address. Bits 0 through 11 of the

counter word contain the count value in BCD format.

Q3) what is the range of the count value of each counter?

ENEE512

--------------------------------------------------------------------------------------------------------

5

Create the following ladder diagram, then test its operation using PLC

SIMATIC C7-621.

Figure 1.3 Create the same program on SIMATIC S5-100U PLC using statement


A I 0.0 L KC 5 S C 1 A I 0.1 CU C 1 A I 0.2 CD C 1 A C 1 = Q 1.0 A I 0.3 R C 1

[E]: Comparison Instructions

Create the ladder diagram in figure 1.4, and then test its operation

using PLC SIMATIC C7-621.

ENEE512

--------------------------------------------------------------------------------------------------------

6

Figure 1.4 Create the same program on SIMATIC S5-100U PLC using statement


A I 0.0 CU C 1 A I 0.1 CD C 1 A I 0.2 L KC 10 S C 1 A I 0.3 R C 1 A C 1 = Q 1.0 L C 1 L KC 5 >=F = Q 1.1

ENEE512

--------------------------------------------------------------------------------------------------------

7

Exercise: Using simatic S5-100U and PG 605U Programmer, write a program that

set an on delay timer to count for 10 seconds, and display the time value (as a

progress bar) on the output port with at least five steps.

Hints:

Timers count down from set value to zero.

Use comparison instructions in your program.

In your program, the comparison must occur only if the timer is set.

You can use KC or KF to load your comparison value to the accumulator.

ENEE512

--------------------------------------------------------------------------------------------------------

8

Experiment#2 Variable Frequency Speed Control

Equipments Required: DL 2309a1 = Digital controlled inverter

M = Asynchronous three-phase motor with squirrel cage rotor

K2 = Optical transducer

G = Electromagnetic brake

K = Torque meter

PS = Brake power supply

Open Loop Speed Regulation

Remote Mode

The object of this exercise is the control of the speed of an asynchronous three-phase

motor by changing the supply frequency with remote mode control of the drive.

Figure 2.1

ENEE512

--------------------------------------------------------------------------------------------------------

9

Procedure:

1. Connect the motor M to terminals L1 (U), L2 (V) and L3 (W).

2. make the following basic settings of DL 2309a1:

Set both key and LOOP switches to "off".

Set JOG switch to "L".

Set P1=0

Set P2 and P3 potentiometers to desired acceleration and deceleration times

(Add 10s for factory default values of parameters P3 and P4).

Set switch "cw/ccw" to "cw" (cw rotation of the motor shaft).

3. Press both ( ) and ( ) keys simultaneously and then switch on the main

supply closing the rear switch.

The display shows [rSt]: release the two keys.

The parameters are reset to factory defaults.

Press (M) key: now the display shows [rdY].

4. Set the frequency control from potentiometer P1(Remote Mode: Parameter

P13/ Mode 0) and the desired frequency range programming the digital

control:

Parameter P1 = (0Hz) minimum operation frequency

Parameter P2 = (60Hz) maximum operation frequency

5. Set the inverter maximum output frequency at which maximum voltage is

reached according to motor specific characteristics ( Motor 1.1kW/220V

/50Hz):

Parameter P7 = (50Hz) base frequency

6. Turn "on" the key switch.

Push "start" button and increase the SPEED signal adjusting the

potentiometer P1 to desired speed value.

The motor has to start with the set acceleration ramp and settle to speed

corresponding to the potentiometer P1 value.

7. The motor revolving speed is directly read on the tachometer, the motor speed

can be changed adjusting the potentiometer P1 value.

ENEE512

--------------------------------------------------------------------------------------------------------

10

8. Stop the motor by setting P1=0 or pressing button "stop": after the motor

deceleration according to the set deceleration ramp, the inverter is inhibited

and the motor stops.

9. Set the key switch to "off" and open the rear main switch.

Open Loop Speed Regulation Local Mode The object of this exercise is the control of the speed of an asynchronous three-phase

motor by changing the supply frequency with local mode control of the drive.

Modify the previous circuit by disconnecting the potentiometer P1.

1. Connect the motor M to terminals L1(U), L2(V) and L3(W).


Set the key switch to "off".






Press (M) key: now the display shows [rdY] .

4. Set the desired motor frequency range programming the digital control:

Parameter P1 = (0Hz) minimum operation frequency

Parameter P2 = (60Hz) maximum operation frequency



/50Hz):

a. Parameter P7 = (50Hz) base frequency

6. With display showing [rdY] enter the local mode:

Press ( ) and ( ) simultaneously: the display will begin to spell LOC.

When all three letters are displayed and the word [LOC] is flashing release

the ( ) and ( ) keys.

The display now shows the local set point of the frequency which can be

increased using the ( ) or decreased using the ( ) key.

ENEE512

--------------------------------------------------------------------------------------------------------

11

Set the running frequency [50.0]: the max running frequency depends on the

Parameter P2 value.

While in the stopped state pressing the (M) red key will show the current

direction: this direction may be changed by holding down the (M) key while

simultaneously pressing either the ( ) key for forward [Frd] or the ( )

key for reverse [rEU].

7. Now the (E) green key can be used to start the inverter.

8. The motor revolving speed is directly read on the tachometer, the motor speed

can be changed pressing either the ( ) key or the ( ) key.

9. Stop the motor by pressing the (M) red key.

10. To return to Remote Mode [rdY] press ( ) and ( ) simultaneously.

11. Open the rear switch.

Jog Speed The object of this exercise is the motor running at Jog Speed.

The same previous circuit.





Set switch "cw/ccw" to "cw"






4. Set the frequency control for Jog speed and for the motor running speed:

Parameter P8 = (30Hz) running freq. the max running frequency

depends on the Parameter P7 value.

ENEE512

--------------------------------------------------------------------------------------------------------

12



/50Hz):


6. Now it is possible to start the motor setting the Jog switch in "H" position: the

motor has to start with the set acceleration ramp and to settle to speed

corresponding to the Jog value.

7. To reverse the direction of rotation of the motor set the "cw/ccw" to "ccw"

position, stop the motor by setting the Jog switch in "L" position. Then open

the rear main switch.

Multistep Control

The object of this exercise is the motor multistep running.


2. Make the following basic settings of DL 2309a1:



Set switch "cw/ccw" to "cw".






4. Set the frequency control for multispeed operation(Remote Mode: Parameter

P13/ Mode 2) and for the motor running speeds:

Parameter P1 = (0Hz)


ENEE512

--------------------------------------------------------------------------------------------------------

13





/50Hz):



Push the "start" button: the motor do not start because the combination

"cw/ccw" =cw / "JOG"=L corresponds to speed preset by the parameter P1.

Operating the switches "cw/ccw" and "JOG" carry out the control sequence

as follows:

a. "cw/ccw"=ccw / "JOG"=L.

b. "cw/ccw"=ccw / "JOG"=H.

c. "cw/ccw"=cw / "JOG"=H.

7. Stop the motor by setting "JOG"=L when "cw/ccw"=cw or pressing button

"stop" , then open the rear main switch.

Motor Power Curve The object of this exercise is the measure of the motor torque versus the absorbed

current for different frequency values.

Connect the circuit in figure 2.2

1. Connect the motor M to terminals L1 (U), L2 (V) and L3 (W) with the ammeter

A to measure the motor current and the voltmeter V to measure the inverter

output voltage.




ENEE512

--------------------------------------------------------------------------------------------------------

14

Figure 2.2






4. Set the desired frequency range programming the digital control:


ENEE512

--------------------------------------------------------------------------------------------------------

15


reached according to motor specific characteristics (Motor 1.1kW/220V

/50Hz):




When all three letters are displayed and the word [LOC] is flashing release

the ( ) and ( ) keys.

The display now shows the local set point of the frequency which can be


Set the first running frequency f1=fB: [50.0].


8. Supply the brake and increase the brake setting by 0.5 N.m up to 4N.m, at

each brake setting measure and record in a table the torque, the voltage and the

absorbed current values.

9. Stop the motor pressing the (M) red key and de-energize the brake.

With standstill motor return to Remote Mode [rdY] pressing ( ) and ( )

simultaneously and set the second running frequency f2 = (40Hz)

Change the Parameter P7= (40Hz).

10. Return to the Local Mode [LOC].

Set the second running frequency f2: [40.0].

11. Start again the motor repeating step 7 and make the measurements following

step8.

12. Repeat for new frequency f3:[60.0].

13. Stop the motor pressing (M) key, de-energize the brake and open the rear main

switch.

14. Construct on a graph the power curves T vs I for different frequency values.

Motor Torque-Speed Curve

The object of this exercise is the measure of the motor torque vs the speed, for

different frequency values.

ENEE512

--------------------------------------------------------------------------------------------------------

16

Connect the following circuit.

Figure 2.3

1. Connect the motor M to terminals L1(U), L2(V) and L3(W) with the ammeter


output voltage.









ENEE512

--------------------------------------------------------------------------------------------------------

17





/50Hz):




When all three letters are displayed and the word [LOC] is flashing releasethe

( ) and ( ) keys.

The display now shows the local setpoint of the frequency which can be


Set the first running frequency f1=fB:[50.0].



each brake setting measure and record in a table the torque , the voltage and

the speed values.

9. De-energise the brake and change the motor speed for a frequency f2 = [25.0]

by pressing the ( ) key.

10. Repeat the measurements following step 8.

11. Stop the motor pressing the (M) key, de-energise the brake and open the rear

switch.

12. Construct on a graph the torque T vs n the speed for the two frequency

values.

Variable Frequency Speed Control The object of this exercise is the measure of the torque-speed curve of the motor-

inverter system.

Connect the same circuit of the previous part.

ENEE512

--------------------------------------------------------------------------------------------------------

18



output voltage.













/50Hz):




When all three letters are displayed and the word [LOC] is flashing releasethe

( ) and ( ) keys.

The display now shows the local setpoint of the frequency which can be


Set the first running frequency f1=fB:[70.0].


ENEE512

--------------------------------------------------------------------------------------------------------

19

8. Supply the brake and increase the brake setting so the motor absorbs a set

current of 4.3A , measure and record in the table the voltage, the speed and

torque values .

9. Decrease the frequency value to 30 Hz value by 5Hz at a time using the ( )

key.

At each frequency setting adjust the brake supply so the absorbed current is

always equal to 4.3A, and measure and record in the table the voltage, the

speed and torque values.

10. Stop the motor pressing the (M) key, de-energise the brake and open the rear

switch.

12. Construct the motor-inverter characteristic curves T vs n and Po vs n.

Closed Loop Speed Regulation The object of this exercise is to check the motor speed regulation by tachometric

feedback.

Connect the following circuit.

Figure 2.4

ENEE512

--------------------------------------------------------------------------------------------------------

20



output voltage.


Set the key switch to "on".


Set P1=0

Set switch " cw/ccw" to "cw"





Press (M) key: now the display shows [rdY].

4. Set the frequency control from potentiometer P1 ( Remote Mode: Parameter

P13/Mode 0) and the desired motor frequency range programming the digital

control:

Parameter P1 = 0Hz

Parameter P2 = 70Hz



/50Hz):



Push "start" button and increase the SPEED signal adjusting the potentiometer

P1 to desired speed value, for example the base frequency fB(50Hz).

ENEE512

--------------------------------------------------------------------------------------------------------

21


each brake setting measure and record in a table the torque , the speed and the

output frequency of the inverter shown on the display.

8. Repeat step 7 for a frequency of 40Hz and 60Hz .

11. Stop the motor pressing the button "stop" and set the key switch to"off", de-

energise the brake and open the rear switch.

12. Construct on a graph the torque T vs n the speed for the different frequency

values.

ENEE512

--------------------------------------------------------------------------------------------------------

22

Experiment # 3 POWER-FACTOR IMPROVEMENT

Object:

To study and examine ways of improving the power-factor of single and 3-phase

induction motors, using capacitors.

Equipment Required:

FH80, FH90.

Voltmeter, Ammeter, Wattmeter.

Capacitors.

Theory:

Power-factor fundamentals:

The usual definition of power factor based on the fact that there are two types of

current in an AC circuit is particularly helpful in understanding the effect of power

factor on system operation and understanding capacitor applications.

Although the following discussion on fundamentals is written around the use of

capacitors because they generally are the most practical and economical means for

improving the PF, these fundamentals also apply to other methods, such as

synchronous motors and condensers.

The current required by induction motors, transformers, fluorescent lights, induction

heating furnaces, resistance welders, etc., may be considered to be made up of two

separate kinds of current: magnetizing current and power-producing current.

Some loads, such as incandescent lights, require only power-producing current.

Power-producing current (or working current) is that current which is converted by

the equipment into useful work such as turning a lathe, making a weld, or pumping

water. The unit of measurement of power produced is the kilowatt (kW).

Magnetizing current (also known as wattles, reactive, or nonworking current) is that

current which is required to produce the flux necessary to the operation of induction

devices. Without magnetizing current, energy could not flow through the core of a

ENEE512

--------------------------------------------------------------------------------------------------------

23

transformer or across the air gap of an induction motor. The unit of measurement of

magnetizing volt-amperes is the kilovar (kVAR).

Total current is the current that is read on an ammeter in the circuit. It is generally

made up of both magnetizing and power-producing currents. The unit of measurement

of total volt-amperes or "apparent power" is the kilovolt-ampere (kVA).

Most AC power systems require both kilowatts and kilovars.

The following useful formulas apply when kW, kVAR, and kVA are substituted for

their respective currents:

(Kva)2 = (Kw)

2 + (Kvar)

2

(Kw)2 = (Kva)

2 - (Kvar)

2

(Kvar)2 = (Kva)

2 - (Kw)

2

Figure 3.1: Diagram showing component current in AC circuit.

What is power-factor:

Power factor may be expressed as the ratio of power-producing current in a circuit to

the total current in that circuit. Another definition of power factor, which is generally

more useful, is the ratio of kW or working power to the total kVA or apparent power.

Thus,

PF = kW/kVA

kW = kVA * PF

kVA = kW/PF

Stated another way, the power factor is that factor by which the apparent power must

be multiplied in order to obtain the working power.

How to improve power factor

KW Current 2 amp

KVAR

Current

2amp

Total

Current

2.83 amps

ENEE512

--------------------------------------------------------------------------------------------------------

24

When the kilovar current in a circuit is reduced, the total current is reduced. If the

kilowatt current does not change, as is usually true, the power factor will improve as

kilovar current is reduced. When the kilovar current becomes zero, all the current is

kilowatt current and therefore the power factor will be 1.0 (unity) or 100%. This could

be done by installing capacitors to supply the load kilovar requirements.

Procedure: I. Single-phase induction motor.

1. Using FH80, connect the circuit as in fig.(2).

Figure 3.2: Capacitor start motor

2. Adjust the voltage to 220V, and progressively increase the torque on

the motor (in steps of 0.2N.m up to 0.8N.m) taking readings of torque,

speed, input power, voltage, and current. Tabulate your results and

complete table 3.1. Plot these data [speed and power factor against

torque].

3. Now connect the capacitor bank across the terminals of the motor as in

figure 3.3.

Figure 3.3: Capacitor start motor with shunt capacitor

4. Repeat step (2) for a capacitor values 3, 5, and 10uF.

Torque Speed Iin V Pin V*I PF Q

0.0

0.2

0.4

0.6

0.8

Table 3.1

ENEE512

--------------------------------------------------------------------------------------------------------

25

II. Three-phase induction motor.

1. Using FH90, connect the circuit as in figure 3.4.

Figure 3.4: phase induction motor -connected

2. Adjust the voltage to 220V, and progressively increase the torque on

the motor (in steps of 0.2N.m up to 0.8N.m) taking readings of torque,

speed, input power, voltage, and current. Tabulate your results and

complete table 3.2. Plot these data [speed and power factor against

torque].

Torque Speed Iin V Pin (3)0.5

V*I Pout PF Q

0.0

0.2

0.4

0.6

0.8

Table 3.2

3. Now connect the capacitor bank (2uF -connected) across the

terminals of the motor as in figure 3.5.

Figure 3.5: 3-phase induction motor -connected with capacitors -

connected.

4. Repeat step (2).

5. Now connect the capacitor bank (6uF Y-connected) across the

terminals of the motor as in figure 3.6.

ENEE512

--------------------------------------------------------------------------------------------------------

26

Figure 3.6: 3-phase induction motor -connected with capacitors Y-connected.

6. Repeat step (2).

Questions:

Single-phase induction motor

1. Complete the VI and PF columns in table(1), and plot on the same

graph the PF against torque for each value of correction capacitor,

including zero capacitance.

2. complete the Q column in table(1), using the values calculated in the

previous question as follows:

Q2 = (VI)

2 – (Pin)

2

Qc = - V2 (2*f* c)

Add the appropriate negative value to the uncorrected average Q

reading calculated earlier. The results should agree fairly closely with

the average Q found experimentally with the used corrective capacitor.

Three-phase induction motor

1. Compute the efficiency with capacitors and without and discuss the

results?

2. Complete the table to find Q in case without and with capacitors?

3. Discuss the results of compensation of reactive power when we are

using Y-connection and delta-connection?

4. Compute Q and compare it at the same PF in Y and delta?

ENEE512

--------------------------------------------------------------------------------------------------------

27

Experiment #4 Introduction to Power World Simulator

Part 1:

Creating a New Case This procedure describes how to create a simple power system model using Power

World Simulator.

To begin, double-click on the Power World Simulator icon. This starts Simulator.

Simulator is used to create new cases, modify existing cases, and (of course) simulate

power systems. In this example, we will build a new case from scratch.

To create a new case, select the File > New Case from the main menu, or click the

open Simulation Case button on the File Palette. The screen background will turn

white, the default background color for new Power World online diagram. Online

diagrams are used in power system analysis to represent the actual three-phase power

system using a single line to represent each three-phase device.

Inserting a Bus

The most important component of the power system model is the bus. Buses are

used to represent junction points in the power system where a number of devices are

connected together. In building a power system model using Simulator, you will draw

buses onto the oneline diagram, attach devices such as generators and loads to the

buses, and connect different buses together with transmission lines and transformers.

Inserting buses on the oneline diagram is very easy:

Select Insert > Bus from the main menu, or select the Bus button on the Insert Palette.

This prepares Simulator to insert a new bus.

Left-click on the oneline background at the location where you want to place the new

bus. This invokes the Bus Option Dialog.

Use the Bus Option Dialog Box to specify the name, size, orientation, area, zone, and

nominal voltage of the bus, as well as the load and shunt compensation connected to

it.

ENEE512

--------------------------------------------------------------------------------------------------------

28

Click OK on the Bus Option Dialog to finish creating the bus and to close the dialog.

After the dialog box closes, the new bus will appear on the oneline at the location you

specified.

For example, let‟s add a bus to the new case. Select Insert > Bus from the main

menu and click somewhere in the middle of the display. The Bus Options Dialog will

open, inviting you to enter information about the bus. The Bus Number fields will

automatically display „1‟. Simulator requires that each bus have a unique number.

For convenience, we will just accept the default value. In the Bus Name field, enter a

name for the bus with up to eight characters. For this example, enter ONE. Next,

check the System Slack Bus field, which is located toward the bottom of the Bus

Information Tab. The Slack Bus is a modeling construct that ensures that the power

system has enough generation to meet the load. In other words, the slack bus "picks

up the slack" caused by system losses. For now, we will just leave the remainder of

the fields with their default values. Click on the OK button at the bottom of the dialog

to insert the bus. You should now see a single horizontal line in the middle of the

oneline; this is your first bus.

Inserting a Generator Next we are going to attach a generator to the bus. Generators may be inserted by

following a procedure that is very similar to the one used for inserting a bus:

Select Insert > Generator from the main menu, or click the Generator button on the

Insert Palette.

Left-click the bus on the oneline diagram to which you want to attach the generator.

This brings up the Generator Option Dialog.

Using the Generator Option Dialog, specify the new generator ‟ s unit identifier,

display size, orientation, MW output and limits, reactive power limits, setpoint

voltage, and cost model.

Select the orientation of the generator; this is the direction in which the generator will

extend from the bus.

ENEE512

--------------------------------------------------------------------------------------------------------

29

Click OK on the Generator Option Dialog to finish creating the generator and to close

the dialog. After the dialog box closes, the new generator will appear on the oneline

attached to the bus on which you clicked in step 2.

Check the Anchored checkbox so that when you move the bus around the oneline the

generator will move with it.

Follow this procedure to attach a generator to the slack bus, bus 1. When the

generator option dialog box appears, simply accept the default fields.

Saving the Case To save the work that we have done so far, select File > Save Case from the main

menu, or click on the Save Case button. Before the case is saved, Simulator

validates the case to make sure that it does not contain any errors. Results from this

validation are displayed in the Message Log display, usually shown in the lower right-

hand corner of the display. If the log is not visible, simply click the Log button on

the Program Palette. Since we have not yet named the case, the Save As dialog is

displayed. Enter the filename and select OK. By default the case is saved using the

Power World Binary format (*.pwb). When saving the case in the future, you will

not have to reenter its name. Simulator also asks you to supply a name for saving the

oneline diagram we have been drawing. The oneline diagram files have a default

extension of *.pwd, which identifies them as Power World Display files. Supply the

same name as you gave to the case. Note that, because the case and the oneline are

stored in separate files, multiple onelines can be assigned to the same case, and the

same oneline can be used by many cases.

Entering a Second Bus with Load To enter the second bus, select Insert > Bus from the main menu or click the Bus

button on the Insert Palette. Then click on the oneline diagram somewhere to the

right of the first bus. The Bus Options Dialog will open .Leave the bus number at the

default value of 2, and enter the name TWO for the bus. We also want to model a 200

MW, 100 MVR load at the bus. To accomplish this, switch to Attached Devices tab

and, under the Load Summary Information heading, click the button labeled Add or

ENEE512

--------------------------------------------------------------------------------------------------------

30

Edit Bus Load. Enter 200 in the MW Value field and 100 in the Mvar Value field.

Click OK to close the load dialog. Click on the OK button at the bottom of the dialog

to insert the bus.

At this point, the oneline diagram does not show the load at bus 2, even though it is

represented in the power system model (you can confirm this by right-clicking on bus

2, selecting Bus Information Dialog from the resulting local menu, and inspecting the

Load Summary Information fields again). To draw the load on the oneline diagram,

select Insert > Load from the main menu, or select the Load button on the Insert

Palette. Now, left-click the mouse near the right edge of this bus. You should

immediately see the Load Options dialog box , whose Constant Power MW and MVR

fields confirm that the load is 200 MW and 100 MVR. In addition to constant power

loads, Simulator also allows the modeling of voltage dependent load.

The Orientation field determines the orientation of the symbol when it is drawn on

the oneline. Check the Up entry to make the load point up. Also, verify that the

anchored box is checked. By anchoring the load to the bus, the load moves anytime

you move the bus. Then click on the OK button to insert the load. A circuit breaker

symbol is automatically included with each load.

Now, try moving bus 2. To do this click somewhere on the bus (not on the load).

Holding down the left mouse, move the bus (this is known as "dragging"). The load

should move as well, because it is anchored. To reposition the load on the bus, simply

click on the load, and then drag it (holding the left button down) to a new position on

the bus.

Inserting a Transmission Line

To connect the two buses together, we will now insert a transmission line between

them. The procedure for inserting a transmission line involves the following steps:

Select Insert > Transmission Line from the main menu, or click the Transmission Line

button on the Insert Palette.

Left-click at the point where you want the new line to originate. This point is usually

located on one of the proposed line‟s terminal buses.

ENEE512

--------------------------------------------------------------------------------------------------------

31

Without holding down the mouse button, drag the mouse. You will notice that a line

segment connected to the point of origin will follow your mouse movements.

Transmission lines and transformers are drawn as a series of line segments. To

terminate a line segment, simply click the left mouse button. To begin drawing the

next line segment, simply move the mouse again. Each time you click the mouse to

terminate a line segment; a new vertex is defined for the line. These vertices may

later be moved or deleted to reshape the line. To create curved lines, hold the left

mouse button down while dragging.

To terminate the final line segment comprising the line (and thus conclude drawing

the line), double click the left mouse button at the point where the line should

terminate. The termination point is usually the line‟s other terminal bus. The

Transmission Line/Transformer Dialog will appear.

Specify the new line‟s parameters using the Transmission Line Dialog and click OK.

The new transmission line will appear on the oneline.

We will now insert a transmission line between buses 1 and 2. Select Insert >

Transmission Line from the main menu, and click at the point on bus 1 at which you

would like the line to start. This begins the process of inserting the line. Move the

cursor upwards a short distance and then click the left mouse button to terminate the

first segment. Then move the mouse horizontally until the cursor is above bus two and

click the left mouse button to define the second segment. Finally, move the cursor

down to the location on bus 2 where you would like to attach the line and double-

click. You should immediately see the Transmission Line/Transformer Dialog. The

dialog should already contain a 1 in the From Bus Number field and a 2 in the To

Bus Number Field. The Resistance, Reactance, and Capacitance fields are used to

enter the per unit parameters associated with the line. The Capacitance field contains

the total per unit charging capacitance for the line. Enter a 0.02 in the Resistance

field, 0.08 in the Reactance field and 0.1 in the Capacitance field. The MVA Rating

field contains the MVA rating for the line; enter a value of 1000.

ENEE512

--------------------------------------------------------------------------------------------------------

32

If the dialog did not contain a „1‟ in the From Bus Number field and/or a „2‟ in the To

Bus Number field, you probably did not have the cursor directly on the bus when you

were drawing the line. Simply enter the correct bus numbers.

Finally, click the OK button to insert the transmission line.

By default, the transmission line is anchored to both terminal buses. If you try to

move bus 2, the transmission line should move with it.

Inserting a Line Flow Pie Chart on a Transmission Line

When the line is drawn it automatically has a line flow pie chart included. You can

include additional line flow pie charts by clicking on the Line Flow Pie Chart button

and then clicking near a line. The Line/Transformer Flow Pie Chart dialog box

appears; make sure that the From Bus and To Bus have the correct numbers that the

MVA rating is correct, and that Anchored is checked; you may change the size of the

pie chart by typing in a value or using the arrows.

Color and behavior of pie charts are set in the Oneline Display Options; right-click

anywhere in the background of the oneline, select Oneline Display Options from the

pop-up menu, and then select the Pie Charts tab.

Inserting Circuit Breakers

We will now place circuit breakers on the line. (If the line already has circuit

breakers at each end, then Simulator has been instructed to insert circuit breakers

automatically. You can configure this option from the Default Drawing Options

Dialog). Circuit breakers are used to control the status of the line. Click somewhere

on the line near bus 1. Then select Insert > Circuit Breaker from the main menu, or

select the Circuit Breaker button and then click on the line near bus 1. You should

immediately see the Circuit Breaker Options dialog with the From Bus and To Bus

fields correctly set to „ 1 ‟ and „ 2 ‟ . If they are „0‟, enter the correct value. Set the

Size field to „1‟ (you can either enter a 1, or use the spin arrows in change the value).

Click the OK button to insert the circuit breaker.

ENEE512

--------------------------------------------------------------------------------------------------------

33

In Simulator, the location of the circuit breaker does not matter, because changing the

status of the circuit breaker changes the status of the entire line. However, since most

transmission lines have circuit breakers at each end, we will also place a circuit

breaker near bus 2. To accomplish this, just repeat the above process near bus 2. Save

your case.

Inserting Text, Bus and Line Fields We are almost ready to run our FIRST case. However, before we do that, we are

going to enter a few informational fields directly on the oneline so that we can see

what is going on in the system more easily. First, we will add a title to the diagram.

Select Insert, Text from the main menu to bring up the Text Object Dialog. Type the

string “First Case and click OK. To make the text look

more like a title, we will do some quick formatting. Select Format, Font to change

the font. This displays the Font Tab of the Format Selection Dialog. Make the font

size 26, and change the font color blue. To change the text background color, select

Format, Line/Fill, this summons the Line/Fill Options Tab of the Format Selection

Dialog. Check the Use Background Fill box to give the text a white background, and

then click OK. Finally, if you would like to move the text, simply left click on it and

drag it to the new location.

Next, we will add several fields that display bus-related quantities. To add fields to

the display of a particular bus, follow this procedure:

Right-click on the bus to bring up the bus‟ local menu.

Select Add New Fields Around Bus from the local menu. This opens the Insert Bus

Fields Dialog.

Use the Insert Bus Fields Dialog to designate the fields to add. You may add up to 8

fields per bus.

Click OK. The specified bus fields will be added to the oneline diagram.

For this example, we will add a Name, Bus Voltage Magnitude, Actual Gen MW, and

Actual Gen MVR fields to bus 1, and Name, Bus Voltage, Load MW, and Load MVR

fields to Bus 2. We can accomplish this in four steps. First, right click on bus 1 and

ENEE512

--------------------------------------------------------------------------------------------------------

34

select the Add New Fields Around Bus option, which brings up the Insert Fields

dialog. Because Bus 1 is horizontal, the possible

Positions for the fields we will be adding are shown in the diagram located in the top

right half of the dialog. We will insert the Name field for bus 1 in position 1 and the

voltage field in position 5.

Use the combo boxes to specify assign the Name field to position 1 and the Voltage

field to position 5, and press OK. The name and voltage fields are to the oneline

diagram around bus 1 in the positions we specified. Repeat this same process for bus

2. If necessary, you may move each of the four newly added fields manually with the

mouse. Next add the Actual Gen MW and

Actual Gen MVR fields to the generator at bus 1. Right-click on the generator and

select the Add New Fields Around Gen option to bring up the Insert Fields dialog.

Since the generator is oriented down, the possible positions for the new fields we are

adding are shown in the rightmost illustration on the top half of the dialog. Use the

dropdown boxes to assign Actual MW to position 1 and Actual MVR to position 2.

Finally, let us add the MW and MVR fields for the load at bus 2. Right-click on the

load and select the Add New Fields Around Load option to invoke the Insert Fields

dialog. Since the bus is oriented upward, the relevant position diagram is the second

one from the left. Use the dropdown boxes to assign MW to position 5 and Mvar to

position 6.

Next we will insert fields showing the power flow on the transmission line. Right

click on the line between buses 1 and 2 and select the Add New Fields Around Line

option to bring up the Insert Fields Dialog. Use the dropdown boxes to assign MW

Flow to position 3 and Mvar Flow to position 4, and MW Flow to position 9 and

Mvar Flow to position 10. Click OK to add the fields

to the oneline. You may need to move the newly inserted fields with the mouse to

improve their appearance.

Solving the Case We are now ready to solve the case. First we need to enter the Run Mode. To do this,

simply click on the Run Mode button on the Program Palette. Note that, if the case

has validation errors, you will need to rectify the problems before you can enter Run

ENEE512

--------------------------------------------------------------------------------------------------------

35

Mode. To start simulating the case, simply select Simulation, Play. Alternatively, to

perform just a single Power Flow Solution,

Click Single Solution on the Program Palette. Try clicking on the load circuit breaker

to toggle the load‟s status. A solid red circuit breaker indicates that it is closed, a

hollow green box indicates it is open. If the Log window is visible, you will get a

“backstage view of what Simulator is doing. Feel free to close the log. Then, with the

load circuit breaker closed, try clicking on a transmission line circuit breaker.

Congratulations, you‟ve just blacked-out your case!

Adding a New Area Next, we will create a second operating area for the case. Large interconnected

systems usually have a number of control areas, with each control area responsible for

the operation of a particular part of the system. Often, a single control area

corresponds to a single owner (such as an investor owned utility), but it is not unusual

for a single control area to have more than one owner. Control areas are connected to

neighboring areas through tie lines. A tie line is a transmission line that has one end in

one control area and the other end in another. The total amount of power flowing out

of a control area is the algebraic sum of the power flowing out on all the area‟s tie

lines. Each control area is responsible for procuring enough power to meet its own

load plus losses. The control area can get this power either by generating it itself, or

by buying it from another area.

This ability to buy and sell power (i.e., power transactions) is one of the principal

advantages of interconnected operation.

To create another control area, go back to editing by clicking the Edit Mode button.

Then add a third bus located below buses one and two. Set the bus number to „3‟ and

the bus name to „THREE‟. Set the Base MW field to 200 and the Base Mvar field to

100. However, in the Area Number field enters „2‟; in the Area Name field enter

„TWO‟. Entering a number for an area that does not already exist automatically

creates a new area. Next, enter a generator and a load at bus three. Then enter a

transmission line between buses 1 and 3 and another between buses 2 and 3.

For each line enter a 0.02 in the Resistance field, 0.08 in the Reactance field, 0.1 in

the Capacitance field, and 400 in the MVA Rating field.

ENEE512

--------------------------------------------------------------------------------------------------------

36

To verify that the case now has two areas, select Case Information, Case Summary.

The Case Information displays allow you to view the entire case using non-graphical

displays. The Case Summary dialog shows the number of buses, generators,

lines/transformers, and control areas in the case. You cannot modify any of these

values. Now we will make sure that both of the control areas are initially set as being

on automatic generation control (AGC). AGC insures that the generation in the area is

equal to the load plus losses plus and scheduled transactions. Select Case

Information, Areas. The Area display provides a convenient summary of all the

control areas in the case. Similar displays exist for buses, generators,

lines/transformers, etc. Right-click

Anywhere on the record for the first area and select the Show Dialog option. The Area

Display Dialog is shown. Change the Area Name to „ONE‟ and set the AGC Status to

ED Control. Select SAVE to save this information. Next click on the up arrow next to

the right of the Area Number field. This displays the Area Record dialog for the next

area. Set the AGC Status to ED Control,

And select OK to save your changes and close the dialog. Close the Area Records

display as well.

Solve the case using the Run Mode. While the simulation is running, click on the

circuit breakers and note the nearly instantaneous change in system flows.

Case Customization Simulator allows you to customize your case in a number of different ways. We will

touch on just two of these options in this section.

For example, suppose we want to prescribe how the load should vary over the course

of the simulation. To accomplish this, first switch back to Edit Mode, and then select

Case Information, Others, Load Variation Schedules from the main menu. The

Load Variation Schedule Dialog will appear. Use the Load Variation Schedule Dialog

to define how load should vary over time. These prescriptions are stored as records

which may then be associated with a particular area or areas to govern how the load

changes in those areas during the simulation. At this time, no load schedules exist, and

you will thus have to define one. Designate the Schedule Type as Daily. Then, edit the

table that lists time points and corresponding load scales such that the load scale is

1.000 at hour 0, 0.8 at 06:00, 1.3 at 12:00, 2.0 at 18:00, and back down to 1.000 at

ENEE512

--------------------------------------------------------------------------------------------------------

37

hour 24:00. This load schedule might approximate a control area‟s typical summer

load variation, with peak load occurring in the late afternoon. Then click the Save

Record As button to save the schedule with name Area1Daily. Then, to associate the

Area1Daily load schedule with Area 1, choose Case Information, Areas from the

main menu. Right-click on the record corresponding to area 1 and select the Show

Dialog option. In the resulting Area Information Dialog, designate the load schedule

as Area1Daily. Then, when you restart the simulation, you will find that load in area 1

will vary according to the Area1Daily load schedule. The same load schedule can be

Applied to the other area in the case, or you may define a new load schedule.

As another example of customization, we will explore how to change the animation of

power flows. Select the Animated Flows Options Tab of the Oneline Display Options

Dialog by selecting Options/Tools, Oneline Display from the main menu. Check the

Show Animated Flows box and the Use Fill Color box. Then select the Change Fill

Color button. Select a greenish

color. Then choose OK to close the Color dialog and OK again to close the Oneline

Display Options Dialog. Save the case and again start the simulation in the Run

Mode. You should see the power flowing down the line. Notice that the load in area 1

is changing and that the generation changes as well to maintain the balance between

supply and demand.

Exercise

Construct the oneline diagram of a four bus system, then solve it using Power World

Simulator, use the following data:

Line data

Line, bus to bus R per unit X per unit C per unit

1-2 0.01008 0.05040 0.10250

1-3 0.00744 0.03720 0.0775

2-4 0.00744 0.03720 0.0775

3-4 0.01272 0.06360 0.1275

Base 100MVA, 230kV

Bus data

Generation Load

Bus P,MW Q,Mvar P, MW Q,Mvar V, per unit Remarks

1 ----- ----- 50 30.99 1.00 Slack bus

2 0 0 170 105.35 1.00 Load bus

3 0 0 200 123.94 1.00 Load bus

4 318 ----- 80 49.58 1.02 PV bus

ENEE512

--------------------------------------------------------------------------------------------------------

38

From the solution at each bus specify the voltage magnitude and angle, and for each

line specify the losses.

Part 2: Building a oneline diagram for an existing case, and other

features of Power World Simulator

Building the oneline diagram Select file, open case to view open dialog

- select PTI Raw File

- open case mdb99s.raw

Prompted to create a oneline; select "yes".

To see information about the case, select case information, case summary

How many buses are in this case and what is the slack bus number is?

In large cases such this case it is useful to use Area/Zone Filters which allow filtering

of most case information display by area or zones.

To display use Case Information, Area/Zone Filters.

Set all areas to "No" except for area IP.

How many buses are there in this area?

To show the complete power flow information for areas with display filter set to "yes"

use Case Information/Power Flow List.

Another feature is the Quick Power Flow List which can be used to show flow at

individual or a set of buses.

To display use Case Information/ Quick Power Flow List, enter bus number 32353,

what data you got?

We are going to create oneline for a portion of the system.

Select insert Bus, click on the oneline towards the top center

ENEE512

--------------------------------------------------------------------------------------------------------

39

For bus number enter 32353, select find by number to view bus info, then select OK

to place the bus.

Repeat this procedure, entering buses 32370 and 32371

Save your case using the default PWB format, the oneline is saved separately as a

PWD file.

Lines between uses can be inserted manually, but it is easier to use automatic line

insertion, select Insert/Auto insert/Lines, select default options then click OK.

You can insert also loads and generators automatically.

Another way to insert buses is the Bus Palette Tool, selects Insert/Show Insert Palette

For/Buses; select a displayed bus to see its displayed and undisplayed neighbors.

Add buses 32364 and 32372, insert transmission lines by selecting insert/auto

insert/lines.

Simulate the case, if all worked fine, you are simulating a 10452 bus case.

Contingency Analysis

Power systems are operated so that overloads do not occur both in real-time and

under any statistically likely contingency. This is often called maintaining system

"security".

Simulator is equipped with tools for analyzing contingencies in an automatic fashion,

contingencies can consist of several actions or elements

- simple example: outage of a single transmission line

- Complex: outage of several lines, a couple generators, and the closure of

normally open transmission line.

Contingency analysis tools can be accessed by selecting Options/Tools, contingency

analysis from the main menu in run mode.

Initially, no contingencies are defined for a case, you can right-click and choose insert

to add them one by one, or load them from a file or auto insert to allow Simulator to

define them.

Open a new case "B7FLAT.PWB", in the Auto-Insertion of Contingencies Dialog

choose Single transmission line, and then select Do Insert Contingencies.

How many contingencies do you have?

To process the contingencies click on Start Run.

ENEE512

--------------------------------------------------------------------------------------------------------

40

How many violations are there and what causes them?

Fault Analysis

Analysis of power system parameters resulting from a ground or line to line fault

some where in the system, simulator contains a tool for analyzing faults in an

automatic fashion, can perform single and three phase faults.

Fault types include:

- Single line to ground.

- Line to line.

- Double line to ground.

- Three phase balanced.

The general fault analysis tool can be accessed from the run mode Options/Tools

menu, or from the run mode toolbar.

Information about the fault location can be filled manually

Alternatively, you can right-click on a bus or transmission line on the one line

diagram, and select Fault… from the menu to have the fault location fields

automatically set.

- Selecting Fault…for a bus will set the bus number field.

- Selecting Fault…for a transmission line will set the from and to bus numbers,

the circuit identifier, and the approximate line location as a percentage of the

length of the line.

Determine which calculations to perform

- Line to ground: assumes phase A to ground

- Line to line: assumes phase B to phase C

- Line to line to ground: assumes phase B to phase C to ground

- Three phase balanced

ENEE512

--------------------------------------------------------------------------------------------------------

41

Fault Analysis Example

Open B7FaultExample.pwb, run the Fault Analysis tool from the run mode

Options/Tools menu. From the Fault Data tab, select fault bus number 3, leave as bus

fault, single line to ground, click calculate

Results are displayed on the five tab sheets on the Fault Data page

Copy all the results into excel and comment on them.

Try to figure out other kinds of faults.

Contouring

Contouring is used to analyze large amounts of information all at once, get an

overview at a glance, monitor and present data.

Contour options dialog is used to control the contouring used on a oneline, it can be

viewed by

- contouring option on oneline local menu

- Options/Tools, contouring on main menu

- Toolbar button on Run Mode toolbar

Open the B7FLAT.PWB case; select Options/Tools, Contouring

In the contouring options dialog select bus, PU volt accept default values, then press

Recalculate Contours button, repeat this but now changing the color values to

maximum 1.05, and minimum to 0.95

What do you notice?

Do contouring for Line MVA Percentage Loadings.

ENEE512

--------------------------------------------------------------------------------------------------------

42

Experiment #5 Three-Phase Banking of Single-Phase Transformers

Object:

To study the phase relationship between primary and secondary windings of a

transformer when connected in different combinations .

Equipments required:

Distribution Transformer Trainer, Voltmeter.

Introduction:

When three single-phase transformers are used to transform a three-phase voltage, the

windings can be connected in several ways. The primaries may be connected in delta

and the secondaries in wye, or vice versa. As a result the ratio of the three-phase input

voltage to the three-phase output voltage depends not only upon the turn's ratio of the

transformers, but also upon how the windings are connected. The figure below shows

various connection configurations.

Figure 5.1

ENEE512

--------------------------------------------------------------------------------------------------------

43

A three-phase transformer bank can also produce a phase shift between the three-

phase input voltage and the three-phase output voltage. The amount of phase shift

depends on the turn's ratio of the transformers, and how the primary and secondary

windings are interconnected.

Procedure: Delta-Delta, 0o Phase Shift Connect the circuit below.

Figure 5.2

Turn on the Distribution Transformer Trainer and determine the voltage between lines

- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

Turn off the Distribution Transformer Trainer. Leave this configuration connected so

as to compare it with the next configuration.

ENEE512

--------------------------------------------------------------------------------------------------------

44

Delta-Delta, 0o Phase Shift vs Delta-Delta, 0o Phase Shift Repeat the circuit shown in the previous part, use transformers T4, T5, and T6 and

lines a2, b2, and c2. Connect bushing X2 of transformer T4 to the ground terminal.


- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------

Turn off the Distribution Transformer Trainer. Leave the configuration connected To

T1, T2 and T3 so as to compare it with the next configuration, and disconnect the

delta-delta configuration, 0o phase shift on T4, T5 and T6.

Delta-Delta, 0o Phase Shift vs Delta-Delta, 180o Phase Shift Connect the circuit shown in the figure below.

Figure 5.3


- a2 and b2 -------------

- b2 and c2 -------------

- c2 and a2 ---------

ENEE512

--------------------------------------------------------------------------------------------------------

45

Determine the voltage between lines

- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------

What can you conclude about the phase shift between lines a1 and a2 ?

Turn off the Distribution Transformer Trainer.

Open-Delta, 0o Phase Shift Connect the circuit below.

Figure 5.4


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------


Do your results demonstrate that it is possible to supply a three-phase load with only

two transformers?

ENEE512

--------------------------------------------------------------------------------------------------------

46

Open-Delta, 0o Phase Shift vs Open-Delta, 0o Phase Shift Repeat the circuit shown in the previous part, use transformers T4 and T5 and lines a2,

b2, and c2. Connect bushing X2 of transformer T4 to the ground terminal.


- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------


Turn off the Distribution Transformer Trainer. Leave the open-delta configuration

connected to T1 and T2 so as to compare it with the next configuration. Disconnect

the open-delta configuration. 0o phase shift on T4 and T5.

Open-Delta, 0o Phase Shift vs Open-Delta, 180o Phase Shift Connect the circuit shown in the figure below.

Figure 5.5


- a2 and b2 -------------

- b2 and c2 -------------

- c2 and a2 ---------

ENEE512

--------------------------------------------------------------------------------------------------------

47


- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------



Wye-Delta Connection Connect the circuit below.

Figure 5.6

Turn on the Distribution Transformer Trainer and determine the voltage between

Terminals H1 and H2 of Transformer

- T1 -------------

- T2 -------------

- T3 ---------

ENEE512

--------------------------------------------------------------------------------------------------------

48


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

What is the phase shift between the primary and secondary voltage?

Turn off the Distribution Transformer Trainer. Leave this configuration connected so

as to compare it with the next configuration.

Wye-Delta vs Wye-Delta Connect the circuit shown in the figure below.

Figure 5.7


- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------



ENEE512

--------------------------------------------------------------------------------------------------------

49

Wye-Delta with Neutral Connect the circuit shown in the figure below.

Figure 5.8


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

- a1 and N ------------

- b1 and N -------------

- c1 and N ------------


Leave the configuration connected so as to compare it with the next configuration.

ENEE512

--------------------------------------------------------------------------------------------------------

50

Wye-Delta with Neutral vs Wye-Delta with Neutral Connect the circuit shown in the figure below.

Figure 5.9


- a2 and b2 -------------

- b2 and c2 -------------

- c2 and a2 ---------

- a2 and N ------------

- b2 and N -------------

- c2 and N ------------


- a1 and a2 -------------

- b1 and b2 -------------

- c1 and c2 ---------



ENEE512

--------------------------------------------------------------------------------------------------------

51

Wye-Delta, Grounded-Y Primary Connect the circuit below.

Figure 5.10


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------


Disconnect the primary of T1.


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

Do your results demonstrate that it is possible to supply a three-phase load with only

two transformers?

ENEE512

--------------------------------------------------------------------------------------------------------

52

Delta-Wye connection. Connect the circuit below.

Figure 5.11


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

- a1 and N -------------

- b1 and N -------------

- c1 and N -------------

- A and B -------------

- B and C -------------

- C and A -------------


ENEE512

--------------------------------------------------------------------------------------------------------

53

Wye-Wye Connection. Connect the circuit below.

Figure 5.12


- a1 and b1 -------------

- b1 and c1 -------------

- c1 and a1 ---------

- A and B -------------

- B and C -------------

- C and A -------------


ENEE512

--------------------------------------------------------------------------------------------------------

54

Experiment # 6 CONTROL OF DC SHUNT MOTOR

Object of Experiment:

1. To study the operation of basic speed control system and observe the

torque/speed characteristics for several settings of the reference voltage.

2. To study the effect of feeding a signal proportional to armature voltage into

the bias circuit of the trigger pulse generator.

3. To study the effect of feeding a signal proportional to armature current into the

bias circuit of the trigger pulse generator.

4. To study the effect of both types of feedback on the performance of the control

system.

SHUNT MOTOR WITHOUT FEEDBACK

Method: ( See Figure 6.1 for basic connections )

1. Connect the armature and shunt field of the motor to the corresponding

terminals on the front panel.

2. Connect the voltmeter and ammeter to measure the mean values of armature

voltage and armature current.

3. Connect the tachogenerator terminals to the speed meter using a jack plug in

the jack socket of the Tachogenerator T100.

4. Do not connect the FLYWHEEL diode.

5. Turn the REFERENCE VOLTAGE to the minimum position.

6. Switch on the supply to the Thyristor Control Unit.

7. Gradually increase the REFERENCE VOLTAGE until the speed of the motor

reaches the maximum value.

8. Check that:

a. The torque indicator is reading upscale when the torque control is

turned up ( if not, reverse the leads to the shunt field ).

b. The speed indicator is reading upscale ( if not, reverse the indicator

leads ).

ENEE512

--------------------------------------------------------------------------------------------------------

55

9. Take readings of motor speed and armature voltage of several positions of

reference voltage, with the torque control at the minimum position.

10. Plot armature voltage against speed.

11. Carry out load tests, with constant reference voltage, for two convenient speed

settings ( Maximum speed, and 800 r.p.m. ). Increase the torque in steps of

0.05 N.m until the motor stalls. Measure torque, speed, armature voltage and

armature current. Plot speed and armature current against torque.

12. Observe the following waveforms using the sockets and terminals provided:-

a. ramp waveform

b. trigger pulse

c. armature voltage

d. armature current

Observe the effect of increasing the reference voltage at no load and the

effect of increasing the torque at constant reference voltage.

Figure 6.1

ENEE512

--------------------------------------------------------------------------------------------------------

56

SHUNT MOTOR WITH ARMATURE VOLTAGE FEED BACK

Method: ( See Figure 2 for basic connection )

1. Add the connection of armature voltage feed back to the circuit of previous

part.

2. Connect FLYWHEEL diode.

3. Turn the REFERENCE VOLTAGE to the minimum position.


5. Gradually increase the REFERENCE VOLTAGE until the motor reaches top

speed.

6. Take readings of motor speed and armature voltage at several settings of

reference voltage. Compare with previous part.

7. Carry out load tests, with constant reference voltage, at 800 and maximum

r.p.m. Increase the torque in steps of 0.05 N.m until the motor stalls. Measure

torque, speed, armature voltage and armature current. Plot speed and armature

current against torque for comparison with graphs already obtained.

8. Observe the following waveforms:

a. trigger pulse

b. armature voltage

Figure 6.2

ENEE512

--------------------------------------------------------------------------------------------------------

57

SHUNT MOTOR WITH ARMATURE CURRENT FEEDBACK

Method: ( See Figure 3 for basic connection )

1. Remove armature voltage feedback and connect armature current feedback.

2. Turn the REFERENCE VOLTAGE and LOAD CURRENT FEEDBACK to

minimum positions.


4. Increase the REFERENCE VOLTAGE until the motor reaches an intermediate

speed.

5. Gradually increase the LOAD CURRENT FEEDBACK. The motor speed will

increase because the positive voltage fed into the bias circuit advances the

trigger pulse.

6. Turn up the torque control to load the motor with fixed settings of reference

voltage and current feedback. Note that increased armature current advances

the trigger pulse and therefore increases the armature voltage. Increase of load

tends to stabilize the motor because there is less torque available for

acceleration.

7. Observe the following waveforms:

a. trigger pulse

b. armature voltage

c. armature current

Figure 6.3

ENEE512

--------------------------------------------------------------------------------------------------------

58

SHUNT MOTOR WITH ARMATURE VOLTAGE AND ARMATURE CURRENT FEEDBACK

Method: ( See Figure 4 for basic connections )

1. Add armature voltage feedback to the circuit of previous part, so that two

feedback signals are applied to the control circuits of the trigger module.

2. Connect FLYWHEEL diode.

3. Turn the REFERENCE VOLTAGE to the minimum position. Select a low

value of CURRENT FEEDBACK.


5. Gradually increase the REFERENCE VOLTAGE until the motor reaches top

speed or instability occurs. If stability does not occur increase the amount of

CURRENT FEEDBACK and repeat.

6. Carry out load testes, with constant reference voltage, at the two speeds

selected in previous parts. For each speed setting select the value of current

feedback which just allows stability at no load. Increase the torque in steps of

0.05 N.m until the motor stalls. Measure torque, speed, armature voltage and

armature current. Plot speed against torque for comparison with the results

already obtained.

Figure 6.4

ENEE512

--------------------------------------------------------------------------------------------------------

59

Experiment #7 Control of Conveyor System Using PLCs and

Sensors Object:

To learn how PLCs are used in automation systems.

To learn how to use sensors in automation systems.

Equipments Required:

SIMATIC S5-100U, PG 605U Programmer, simple conveyor belt, proximity sensor,

switch relays, DC power supply, DC motor.

Procedure: A) Controlling a conveyor belt.

The following figure shows a conveyor belt that can be activated electrically. Two

start buttons is used to move the conveyor belt in both directions, and one button is

used to stop it. The sensor is used to detect metallic items such that when the item

reaches the sensor, the conveyor belt stop.

Figure 7.1

Write the following program and use the proper connections using switch relays to

control the conveyor belt. Use absolute addresses instead of the symbolic addresses.

A START_RIGHT AN MOTOR_ON_LEFT S MOTOR_ON_RIGHT A START_LEFT AN MOTOR_ON_RIGHT

ENEE512

--------------------------------------------------------------------------------------------------------

60

S MOTOR_ON_LEFT O STOP O SENSOR R MOTOR_ON_RIGHT R MOTOR_ON_LEFT

B) Controlling Storage Area with Counter and Comparators. In this part, the conveyor belt is used to deliver items to a temporary storage area and

to transport these items from that storage area. Using a proximity sensor, we must

keep track of the number of items in the storage area. When the conveyor belt is on in

the right direction, it delivers items to the storage area, while when it is on in the left

direction, it transport items from the storage area.

Modify the following program and write it and test its operation.

ASTART_DELIVER

AN MOTOR_ON_TRANSPORT S MOTOR_ON_DELIVER A START_TRANSPORT AN MOTOR_ON_DELIVER S MOTOR_ON_TRANSPORT A STOP R MOTOR_ON_DELIVER R MOTOR_ON_TRANSPORT A SENSOR A MOTOR_ON_DELIVER CU COUNTER A SENSOR A MOTOR_ON_TRANSPORT CD COUNTER A COUNTER = ONE_ITEM L COUNTER L KC 2 >=F = TWO_ITEMS L COUNTER L KC 3 >=F = THREE_ITEMS L COUNTER L KC 4 >=F = FOUR_ITEMS L COUNTER L KC 5

ENEE512

--------------------------------------------------------------------------------------------------------

61

>=F = FIVE_ITEMS L COUNTER L KC 6 >=F = FULL A FULL R MOTOR_ON_DELIVER AN COUNTER R MOTOR_ON_TRANSPORT

ENEE512

------------------------------------------------------------------------------------------------------------

62

Experiment #9 Creating a Program with Function Blocks and Data

Blocks Using Siemens PLCs

Objectives: To learn how to create a PLC program with function blocks and data blocks using

step 7 software tools. And to test this program using Siemens PLCs.

To show you how to program a function block which can, for example, control and

monitor petrol or diesel engine using two different data blocks.

Equipment Required:

SIMATIC C7-621 PLC, STEP 7 programming software.

Procedure: Create new step 7 software project using SIMATIC Manager program.

Select the C7-621 hardware from SIMATIC 300>>C7

Open the S7 Program (1) folder and double click on the Symbols icon to open the

symbol table.

Fill the symbol table as follows:

Table 9.1

ENEE512

------------------------------------------------------------------------------------------------------------

63

A) Creating and Opening Function Blocks (FB)

The function block (FB) is below the organization block in the program hierarchy. It

contains a part of the program which can be called many times in OB1. All the formal

parameters and the static data of the function block are saved in a separate data block

(DB), which is assigned to the function block.

You will program the function block (FB1, symbolic name "Engine") in the

LAD/STL/FBD program windows.

Navigate to the Blocks folder and open it.

Click in the right-hand half of the window with the right mouse button.

The pop-up menu for the right mouse button contains the most important

commands from the menu bar. Insert a function block as a new object

Double-click FB1 to open the LAD/STL/FBD program windows

In the "properties --- Function Block" dialog box, select the language in which

you want to create the block, activate the check box "Multiple instant FB" and

confirm the remaining setting with OK.

The function block FB1 has been inserted in the Blocks folder.

ENEE512

------------------------------------------------------------------------------------------------------------

64

B) Programming FB1 in Ladder logic

We will now show you how you can program a function block which can, for example,

control and monitor a petrol or diesel engine using two different data blocks.

All "engine-specific" signals are passed on as block parameters from the organization

block to the function block and must therefore be listed in the variable declaration table

as input and output parameters (declaration "in" and "out")

You should already know how to enter a series circuit, a parallel circuit, and a memory

function with STEP 7.

Filling out the Variable Declaration Table

Your LAD/STL/FBD program windows is open and the option View>LAD(

programming language) is activated.

Enter the following declaration in the variable declaration table. To do this, click

a cell and use the corresponding name and the comment from the illustration

below.

You can select the type with the pop-up menu command Elementary Types using

the right mouse button. When you press Enter, the curser jumps to the next

column, or a new row is inserted.

Table 9.2

Programming an engine to Switch On and Off

ENEE512

------------------------------------------------------------------------------------------------------------

65

Build the following Circuit in FB1. this circuit controls the switching on and off

of the engine.

Figure 9.1

Programming Speed Monitoring Add a new network in FB1, and build the following circuit which monitors the

speed of the engine.

Figure 9.2

Then save your program and exit FB1.

C) Generating Instance Data Blocks and Changing Actual Values

You have just programmed the function block FB1 ("Engine") and defined, among other

thing, the engine-specific parameters in the variable declaration table.

ENEE512

------------------------------------------------------------------------------------------------------------

66

In order for you to be able to program the call for the function block in OB1 later on, you

must generate the corresponding data block. An instance data block (DB) is always

assigned to a function block.

The function block is to control and monitor a petrol or diesel engine. The different set

point speeds of the engines are stored in two separate data blocks, in which the actual

value (#Preset _Speed) is changed.

By centrally programming the function block only once, you can cut down on the amount

of programming involved.

Navigate to the Blocks folder and click in the right half of the window with the right

mouse button.

Insert a data block using the pop-up menu with the right mouse button.

Accept all the setting displayed in the "properties" dialog box with OK. The data

block DB1 is added to your project.

Double-click to open DB1.

Activate the option Data block referencing a function block in the "New Data

Block" dialog box.

Confirm the assignment "FB1, Engine" with OK. The LAD/STL/FBD program

window opens with the data from the variable declaration table for FB1. DB1 is

now to contain the data specific to a petrol engine. You still have to enter these

data. First set the Data View.

Next enter the value "1500" for the petrol engine in the Actual Value column (in the

row "Preset_Speed"). You have now defined the maximum Speed for this engine.

Save DB1 and chose the program window.

In the same way as for DB1, generate another data block, DB2, for FB1.

Now enter the actual value "1200" for the diesel engine.

Table 9.3

ENEE512

------------------------------------------------------------------------------------------------------------

67

D) Programming a block cell in the ladder Logic.

All the work you have done programming a function block is of no use unless you call

this block in OB1. A data block is used for each function block call, and in this way , you

can control both engines.

Figure 9.3

Navigate to the Blocks folder and open OB1.

Then navigate in them Program Elements catalog until you reach FB Blocks>>FB1

and insert this block. And complete the circuit as follows.

ENEE512

------------------------------------------------------------------------------------------------------------

68

Figure 9.4

Insert two new network in OB1, and use two move blocks to enter values to the

DE_Actual _Speed and the PE_Actual _Speed.

Navigate to the blocks folder and open it. Then download all the function and data

blocks, and also download OB1 on the SIMATIC C7-621 PLC, and test its

operation.

Note: To download any Block, right click on that Block, and select from the pop-up

menu PLC>> Download.

Enter several values of Actual Speeds, and see the effect on the output.

ENEE512

------------------------------------------------------------------------------------------------------------

69

Experiment 10 Bus bar Simulator

Switchgear system forms a central part in the distribution of energy. Their correct

functioning ensures uninterrupted supplies of electrical energy.

Introduction to the subject

ENEE512

------------------------------------------------------------------------------------------------------------

70

Busbars are an important part of switchgear systems. Their function is to provide a

collecting point for in-coming electrical energy and to distribute this energy to where it

nay be required. In this way, one supply can provide energy to several outputs. Large

switchgear systems often have two supply sources. These switchgear systems can be pure

distribution systems, or when transformers are included with the directly-served

consumers, they are then known as power transforming stations.

The safety in the supply of electrical energy is dependent, amongst other factors, on a

clear construction of the switch gear system and an orderly layout of the operator console

of the control unit. Switching errors must at all costs be avoided; then only power switch

modules can be used for switching voltage-carrying circuits; straightforward isolating

circuit breakers are not suitable here.

Larger systems and those for supplying particularly important switchgear systems,

employ double busbars.

Procedure

1) Manual Busbar Change (control the busbar simulator manually ).

Connect the Busbar simulator SE 2663-8G at the INPUT and socket N (blue) to a

source of 230 V AC having identical frequency, magnitude and phase to

termination 1 and 2.

Connect the d.c. input voltage ± to 24 V.

Connect the housing to the PE terminal.

The maximum power consumption in the a.c section is in the order of 23 VA and

approximately 0.5 A at 24 V (without PLC) (12 W).

The system is now ready for operation.

ENEE512

------------------------------------------------------------------------------------------------------------

71

Figure 10.1

A) Operating the switchgear system with 1 supply transformer, 2 Outputs

(Consumers) with only busbar.

Initial position of all circuit breakers and power switches in the off-setting.

All error acknowledge control switch in off-setting (i.e all levers are horizontal, all lamp

are off).

Switching on Test field 1

1. Switch Circuit breaker Q11 of Test field 1 On:

Turn lever of Q11, 900 cw; the Acknowledge lamp lights. Then allow the lever

to detent and turn a further 200 until the Acknowledge lamp in the lever is

extinguished. The circuit breaker is now switched on.

Circuit breaker Q12 remains initially open.

Switching sequence when selecting busbar 1

2. Switch on Circuit Breakers Q31 of supply field 1.

ENEE512

------------------------------------------------------------------------------------------------------------

72

Turn lever of Q31, 900 cw; the lamp lights. Allow the levers to detent and turn a

further 200 until the lamp is extinguished. The Circuit breaker is now switched on

and is connected to busbar I (SS I) .

Switching on Supply 1

3. Switch on power switch Q33 of supply field 1.

-Turn lever of Q33, 900 cw; the lamp lights. Allow the lever to detent and turn a

further 200 until the lamp is extinguished. The power switch is now switched on.

What indication of the bus bar voltage in the test field of busbar 1?

Switching Output 1 to busbar 1

Set the load potentiometer of output 1 in area 2 to a scale value of 5

4. Switch on circuit breaker Q21 of Output 1 in Area 2 to a scale value of 5

- Switching sequence as described above.

Switching output 1 to current consumption.

5. Switch on power switch Q23 of output 1:

- switching sequence as described above: turn by 900, detent, turn further, wait till

lamp is extinguished.

What does the ammeter indicate?

Switching output 2 to busbar 1

Set the load potentiometer of output 2 in area 5 to a scale value of 9

6. Switch on Circuit breaker Q51 of Output (consumer) 2

Switching output 2 to current consumption

7. switch on Power switch Q53 of Output 2

What are the new indications of the Ammeters?

ENEE512

------------------------------------------------------------------------------------------------------------

73

Figure 10.2

B) Inserting a second Supply to the same bus bar at switch state A

Switching sequence

1. Switch on circuit breaker Q61 of supply 2:

- Turn lever of Q61 by 900 cw, detent and turn further until the Acknowledge lamp is

extinguished. Circuit breaker Q61 is now connected to bus bar 1.

2. Switch on power switch Q63 of supply 2.

Now what are the new meters indications? What are the relation between these

readings?

ENEE512

------------------------------------------------------------------------------------------------------------

74

Figure 10.3

C) Switching off a Supply when operating B switching?

Switching sequence for switching off supply 1

1. Switch off power switch Q33 of supply 1:

- turn lever of Q33 by 900, ccw

The acknowledge lamp lights and indicates that the acknowledge switch is at the off

position, but the power switch is not. Therefore, detent the lever of Q33 and turn ccw

until the lamp is extinguished. The power switch Q33 is now switched off.

What are the new indication of the meters?

2. Switch of Circuit breaker Q31 of Supply:

- Turn lever of Q31 by 9000, ccw.

The Acknowledge lamp lights (analog to Q33). Detent the lever and turn ccw by 200

until the lamp is extinguished. The circuit breaker Q31 is now Switched off.

ENEE512

------------------------------------------------------------------------------------------------------------

75

Figure 10.4

D) Operating busbar II with Supply 1 and interruption-free change-over of

output 1 from busbar I to busbar II

Initial state: circuit C

Switching on the test field, busbar II

1. Switch on the Circuit breaker Q12 on the test field

Switch supply 1 to busbar II

2. Switch on Circuit breaker Q32 of Supply 1.

3. Switch on Power switch Q33 for Supply 1.

What new indications appear?

ENEE512

------------------------------------------------------------------------------------------------------------

76

Coupling busbar I and busbar II

Prequisite: Voltage on SS I and SS II are identical in magnitude, frequency and phase.

4. Switch on Circuit breaker Q41 of Coupling field 4.

5. Switch on Circuit breaker Q42 of Coupling field 4.

6. Switch on Power switch Q43 of Coupling field 4.

What are the new indication of ammeters?

Interruption-free change-over of Output 1 to busbar II

Since the coupling field switch is closed and thus, the samepotential is present on

busbars I and II, Circuit breaker Q22 of Output 2 may be switched on and its isolator

Q21, switched off. Although a current is present, no power is being switched, as can be

followed bellow:

7. Switch on Circuit breaker Q22

What is a new indication of coupling current?

8. Switch off Circuit breaker Q21

The coupling field must now be switched back to its neutral position.

The switching sequence described below must be followed:

9. Switch off power switch Q43 in the coupling field

10. Switch off Circuit breakers Q41 and Q42 of the Coupling field, one after the other.

ENEE512

------------------------------------------------------------------------------------------------------------

77

Figure 10.5

2) Automatic bus busbar Change, using a PC.(Control the bus bar simulator using

computer).

In this method we can switch on or off the bus bar components simply using the mouse

by clicking on the desired element.

Repeat section A and B using the automatic busbar change method.

512 manual

Documents