electrical power distribution & utilization - ned university

PRACTICAL WORK BOOK

For Academic Session 2013

ELECTRICAL POWER DISTRIBUTION & UTILIZATION (EE-357)

For TE (EE)

Name:

Roll Number:

Class:

Batch: Semester/Term:

Department :

Department of Electrical Engineering NED University of Engineering & Technology

SAFETY RULES

1. Please don t touch any live parts. 2. Never use an electrical tool in a damp place. 3. Don t carry unnecessary belongings during performance of practicals (like

water bottle, bags etc). 4. Before connecting any leads/wires, make sure power is switched off. 5. In case of an emergency, push the nearby red color emergency switch of the

panel or immediately call for help. 6. In case of electric fire, never put water on it as it will further worsen the

condition; use the class C fire extinguisher.

Fire is a chemical reaction involving rapid oxidation (combustion) of fuel. Three basic conditions when met, fire takes place. These are fuel, oxygen & heat, absence of any one of the component will extinguish the fire.

If there is a small electrical fire, be sure to use only a Class C or multipurpose (ABC) fire extinguisher, otherwise you might make the problem worsen.

The letters and symbols are explained in left figure. Easy to remember words are also shown.

Don t play with electricity, Treat electricity with respect, it deserves!

Figure: Fire Triangle

A(think ashes): paper, wood etc

B(think barrels): flammable liquids

C(think circuits): electrical fires

Electrical Power Distribution & Utilization Contents

NED University of Engineering and Technology Department of Electrical Engineering

Prepared by: Muhammad Mohsin Aman 2012

CONTENTS

Lab.

No. Dated Title of Experiments

Page No

Remarks

1 Parts of power cable. 1 - 3

2 Cable Size Calculation for the given load.

4 - 7

3 Measure the High Level Voltage, Current and Resistance using Instrument Transformers & Megger.

8 - 9

4 Operation and constructional features of a Distribution Transformer.

1 0 - 1 1

5 Substation Equipments and its one-line diagram.

1 2 - 1 5

6 Power Factor Improvement 1 6 - 1 9

7(a)

7(b)

Using Calculux

First project on design of general lighting scheme for an office.

20 - 2 2

23-24

8(a)

8(b)

Second project on design of general lighting scheme for an office. To design a task & accent lighting for an office (optional).

2 5 - 2 7

2 8 - 2 9

9 Different types of lamps & comparing the Illuminance level.

30 - 3 2

10 Calculate the charges in Industrial/commercial bill.

3 3- 36

11 Captive Power Generation (DG Set-Diesel Generating Set). optional

3 7 - 40

12 Home El ectrical Wiring 4 1 - 4 3

13 Earth Resistance and Soil Resistivity Measurment

4 4- 50

Electrical Power Distribution & Utilization Lab Session 01


- 1 -

LAB SESSION 1

Power Cable

OBJECTIVE

To dissect the power cable into it s distinguished parts.

APPARATUS

Dissected Cables

Vernier Calliper

Screw Gauge

THEORY

A cable is defined as an assembly of conductors and insulators used for the transfer of power in densely populated urban areas. Cables are mostly laid under the ground in order not to disturb the land beauty and to avoid using the land for power transmission purposes.

Figure: Parts of cables

PARTS OF CABLE A cable is composed of the following parts;

Core All cables either have a central core (conductor) or a number of cores made of strands of Copper or Aluminum conductors having highest conductivity. Conductors are stranded in order to reduce the skin effect.

Insulation It is provided to insulate the conductors from each other and from the outside periphery. The common insulating materials are Poly Vinyl Chloride (PVC) and Polyethylene.

Metallic Sheath Metallic Sheath protects the cable against the entry of moisture. It is made of lead, some alloy of lead or Aluminum



- 2 -

Bedding In order to protect the metallic sheath from injury, bedding is wound over it. It consists of paper tape compounded with a fibrous material.

Armoring It consists of one or two layers of galvanized steel wires or two layers of steel tape, to avoid the mechanical injury. Armoring provides mechanical strength to the cable.

Serving A layer of fibrous material, used to protect the armoring.

Figure: Cross Sectional View of Cable

S. No

Properties Copper Aluminum

Annealed

Hard Drawn

Annealed Hard

Drawn

1 Resistivity at 20 C (ohm-m × 10-8)

1.72 1.78 to 1.8

2.8 2.3

2 Temperature coefficient of electrical resistance at 20 C

0.00393 0.00393 0.00403 0.00403

3 Coefficient of linear expansion per unit per C

17.0 x 10-6 17.0 x 10-6 23.0 x 10-6 23.0 x 10-6

4 Thermal conductivity W/mK

384 384 209.4 209.4

5 Density kg/m3 8.89 x 10-3

8.89 x 10-3

2.71 x 10-3

2.71 x 10-3

6 Specific heat kJ/kg K 0.394 0.394 0.904 0.904

PROCEDURE

Practical demonstration

RESULT

Cables have been studied and their operation is understood.



- 3 -

EXERCISE:

You are given three cables of unknown cross section: find out the following information about each cable.

S. No

No. of Cores

No. of Strands

Diameter (m)

Cross Sectional Area (mm2) Nomenclature

1 2 3

Give the definition of following terms: 1. Coefficient of linear expansion 2. Temperature coefficient 3. Thermal conductivity 4. Resistivity 5. Ampacity

Explain the following processes: 1. Annealing & Importance 2. Galvanizing 3. Vulcanizing

Give short answers to the following questions: 1. What will be the difference in size of Cu & Al conductor for same installation?

(Hints: refer table) 2. Why do we use ACSR conductors for transmission not in distribution? 3. Mostly Aluminum is used in transmission system as a conductor, why not Cu as a

conductor?

______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________



- 4 -

LAB SESSION 02 Select the Appropriate Cable Size

OBJECTIVE

Select the appropriate cable size for the given load.

APPARATUS

Given Load

Cable Tables Book

THEORY

The cable selection procedures set out in this LAB SESSION will give the basic guidelines to be followed to determine the minimum size of cable required to satisfy a particular installation condition.

The following three main factors influence the selection of a particular cable to satisfy the circuit requirements:

(a) Current-carrying capacity dependent upon the method of installation and the presence of external influences, such as thermal insulation, which restrict the operating temperature of the cable. (b) Voltage drop dependent upon the impedance of the cable, the magnitude of the load current and the load power factor. (c) Short-circuit temperature limit dependent upon energy produced during the short-circuit condition.

TASK: Determine the size of cable required & voltage drop in the cable.

SITUATION: A 150kW, three phase load is supplying from a 400V, 50Hz supply. The circuit is protected using BSEN 60898 Type B circuit breaker and is situated 150m away from the distribution board. It is run with two other power circuits and is buried in the ground at a depth of 0.8m. There the soil resistivity is 1.2 ºC.m/W. The temperature within the installation can be assumed to be 30 C. Calculate the size of cable required, assume armored Cu cable is used here.

DB

150 kW LOAD

150m



- 5 -

METHOD:

STEP #01

Determine the current requirements of the circuit. This current is known as Design current, either specified by the manufacturer or can be calculated by the formulae.

Design Current (IN) = kilo Watt Power (For 1 phase) Single Phase Voltage x power factor

Design Current (IN) = kilo Watt Power (For 3 phase) 3 x Line Voltage x power factor

If kVA power is given the above formula will change accordingly. If motor power is given in hp then use the conversion 1hp=746 Watts.

Here,

Design Current (IN) = _______________________ = Amps

STEP #02

Determine the method of cable installation to be used.

Installation Conditions: The current-carrying capacity of a cable is dependent on the method of installation to maintain the temperature of the cable within its operating limits. Different methods of installation vary the rate at which the heat generated by the current flow is dissipated to the surrounding medium.

Specific conditions of installation are there like cables installed with or without wiring enclosures in air, in the ground or embedded in building materials.

STEP #03

Determine the environmental conditions in the vicinity of the cable installation, where applicable, like

(i) the ambient air or soil temperature (ii) the depth of laying rating factor (iii) the soil thermal resistivity rating factor

Use any cable s table book to find out the correction factor values.

Here, the correction factors from the tables:

Grouping Factor (Cg): _______

Ambient Temperature (Ca): _______

Soil Resistivity Factor (Cr): _______

Depth of laying factor (Cd): _______

STEP #04

Apply the correction factors to determine the current carrying capacity (Ic) of the cable by using the formula.

Current carrying capacity of cable = Design current .



- 6 -

Correction Factors The above factors should be applied according to the design situation.

Current carrying capacity of cable = ____Design current .

Cg x Ca x Cr x Cd

Here, Current carrying capacity of cable = ________________________

Current carrying capacity of cable = ______________

Minimum cable size = _____________ mm2

Finding the Protective Device Size (IF).

The design current should be no greater than the fuse rating. The fuse rating must be no greater than the current carrying capacity of the cable. The current carrying capacity of the cable should not be greater than the tabulated capacity of the cable i.e.

IN IF IC

The Worst-Case Scenario

A cable may experience various different environments along its route. For example it may start at a switchboard, run through the switch room in a trench with a lid or steel flooring, pass through a duct in a wall and under a roadway, run a long way directly buried and finish on a ladder rack at the consumer. At each of these environments the thermal resistivity and ambient temperature will be different. The environment that causes the most derating of the rated current should be taken and used for the whole cable.

DETERMINATION OF VOLTAGE DROP FROM MILLI VOLTS PER AMP -METRE

According to IEE Regulation 522-8 of the 15th edition, it is stipulated that: The voltage drop within the installation does not exceed a value appropriate to the safe functioning of the associated equipment in normal service. For final circuits protected by an over current protective device having a normal current not exceeding 100A, this requirement is deemed to be satisfied if the drop in voltage from the origin of the circuit to any other point in the circuit does not exceed 2.5 percent of the nominal voltage at the design current, disregarding staring conditions.

The voltage drop can be determine using the following formula 50 for applications where only the route length and load current of balanced circuits are known.

Voltage Drop (Vd) = L x IN

x Vc .

1000 where Vc = the millivolt drop per ampere-metre route length of circuit, as shown in the tables for various conductors, in millivolts per ampere metre (mV/A.m)

Vd = actual voltage drop, in volts L = route length of circuit, in meters IN = the current to be carried by the cable, in amperes.

Here, L = 80m



- 7 -

IN = __________ Amps Vc= __________ mV/A.m

Voltage Drop (Vd) = _________________

1000

Voltage Drop (Vd) = _______ i.e. % of 400V.

Hence the selected cable of mm2 is suitable for normal current of Amps & cable length of 80m.

EXERCISE:

Repeat the above task (i) With load 20kW at power factor 0.9. (ii) With L = 130 m (iii)Assume unarmored cable is used here installed in air.

Answer:

(i) mm2

(ii) mm2

(iii) mm2



- 8-

LAB SESSION 03

Measure the High Level Voltage, Current and Resistance

OBJECTIVE

Using measuring instruments measure the high level of voltage, current and resistance.

APPARATUS

Current Transformer

Potential Transformer

Megger

Clip on Ammeter

THEORY

Current Transformers Ammeters are employed for measurement of current in circuits. In high voltage transmission lines, it is more feasible to use Current Transformers for measurement of current owing to its higher range of measurement. High values of currents flowing in the transmission lines serve as the primary circuit of a current transformer. The high current is stepped down to a much lower value (normally not more than 5A) which is then measured by an ordinary ammeter. This way, an ammeter is not exposed to high currents and voltages.

Potential Transformers For measurement of high voltages, potential transformers are commonly used. Difference between the potential transformers and current transformers is that Current Transformers are connected in series whereas Potential Transformers are connected in parallel.

Among the available range of PTs and CTs, the selection is based on the following factors

Insulation Class

Primary to Secondary ratio

Continuous thermal rating

Service conditions

Accuracy

Clip On Ammeter Current is measured only when an ammeter is connected in a circuit in series. What if the current in any wire connected to a load is required to be measured. Using an ammeter, we shall first need to disconnect the load from the source, insert an ammeter and then measure the current. Instead of doing all this, a clip on ammeter allows current measurement without disconnecting the line. It operates on the concept of transformation, as in transformers where flux linkages produce voltages.



- 9-

Megger Megger is a name given to an instrument used to measure large values of resistance. Measuring resistance of machines and devices is very helpful in determining faults like short circuits etc. Once a machine faces a fault, its internal resistance gets changed. Machine resistance is regularly monitored in order to detect any internal faults occurring in the machines and other devices.

OBSERVATION

Using Clip on Ammeter measure the current of a single phase load.

Load Measured Value (A) Using Clip on Ammeter

Calculated Value(A) Using Formula

Pedestal Fan ( W)

100W bulb

Tube light ( W) with ballast ( W)

Two 100W bulbs in parallel

Desktop PC (Personal computer) ( W)

Using CT (current Transformer) measure the current of a given load.

CT ratio: ________

Load Primary Current (Using Clip On Ammeter)

Secondary Current of CT

1000W

2000W

3000W

Using Megger find the insulation Resistance of 1. A new cable _____________________ found to be___________________

2. An old cable______________________ found to be___________________

3. Across Burnt Motor Terminals______ found to be___________________

4. _________________________________ found to be___________________

RESULT

Working of measuring instruments practically demonstrated.

Electrical Power Distribution & Utilization Lab session 04


- 10-

LAB SESSION 04

Distribution Transformer

OBJECTIVE

To study the operation and constructional features of a Distribution Transformer

APPARATUS

Distribution Transformer

THEORY

Distribution transformer is used to convert electrical energy of higher voltage (usually 11-22-33kV) to a lower voltage (250 or 433V) with frequency identical before and after the transformation. Its main application is mainly within suburban areas, public supply authorities and industrial customers. With given secondary voltage, distribution transformer is usually the last in the chain of electrical energy supply to households and industrial enterprises.

Power Transformer

CONSTRUCTION There are 3 main parts in the distribution transformer:

Coils/winding

where incoming alternating current (through primary winding) generates magnetic flux, which in turn induces a voltage in the secondary coil.



- 11-

Magnetic core

material allowing transfer of magnetic field generated by primary winding to

secondary winding by the principle of electromagnetic induction.

A transformer s core and windings are called its Active Parts. This is because these two are responsible for transformer s operation.

Tank

serving as a mechanical package to protect active parts, as a holding vessel for

transformer oil used for cooling and insulation.

Transformer Accessories

Breather

Pressure relief device

Temperature Indicator

Tap Changer etc

SIGNIFICANCE OF VECTOR GROUPS Three phase machines, such as transformers, are allotted symbols representing the type of phase connection and the phase angle between the HV and LV terminals. The angle is described by a clock-face hour figure. The HV vector is taken as 12 o clock, the reference, and the corresponding LV vector is represented by the hour hand.

For example, a Dy11 represents; D = HV winding is delta connected y = LV winding is star connected 11 = clock-face reference indicating that the LV vector is at 11 o clock (30o lead) with reference to the HV vector.

PROCEDURE

Practical demonstration.

RESULT

Complete working of the distribution transformer has been understood.

EXERCISE:

Give the purposes of following parts of Distribution Transformer

1. Bushings 2. Conservator or expansion tank 3. Breather 4. Pressure relief device 5. Tap Changer (OFF Load)



- 12-

LAB SESSION 05

Substation Equipments & One Line Diagram

OBJECTIVE

To study the major equipments of the substation and make a one-line diagram.

APPARATUS

A visit will be arranged to a sub-station.

THEORY

An electrical substation is a subsidiary station of an electricity generation, transmission and distribution system where voltage is transformed from high to low levels using transformers. Electric power may flow through several substations between generating plant and consumer, and may be changed in voltage in several steps.

Feeders The electrical distribution system begins with a source of electrical energy that must be distributed to each and every electrical load. The starting point of this system, which feeds electrical energy into it, is known as a Feeder. The electricity delivered by a feeder is actually distributed to different loads in the system.

Distributors A distributor is a conductor from which tapings are taken to the consumers. The current through a distributor is not constant due to the tapings taken off at various places along its length. While designing a distributor, voltage drop along its length is the main consideration as the voltage variation limits are about 6% of the rated voltage at the consumer terminals.

Switch Gears The term switchgear, used in association with the electric power system, or grid, refers to the combination of electrical disconnects, fuses and/or circuit breakers used to isolate electrical equipment. Switchgear is used both to de-energize equipment to allow work to be done and to clear faults downstream Panels are the compartments used for switchgear arrangement.

Switching Devices A device designed to close, open, or both, one or more electric circuits. These include

HRC fuses

Magnetic contactor

Circuit Breaker (Molded Case Circuit Breaker)

Load Break Switch



- 13-

Figure: Fuse

Figure: Contactor

Figure: Circuit Breaker

One line diagram of a typical distribution system

EXERCISE:

1. Using Magnetic Contactor design and implement the DOL circuit for three phase Induction Motor. Also explain working.



- 14-

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ __________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________

2. Using Magnetic Contactors design a Star Delta Scheme for three phase Induction Motor. Also explain working.

______________________________________________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________



- 15-

______________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________________



- 16-

LAB SESSION 06

Power Factor Improvement OBJECTIVE

To improve the power factor of distribution load

APPARATUS

Delta Connected Capacitor Bank (Module AZ-191b)

Multimeter

Energy Analyzer

Resistive Load Bank

Inductive Load Bank

THEORY

The ratio of the actual power consumed by equipment (P) to the power supplied to equipment (S) is called the power factor.

S

P

werApparentPo

alPowerCosrPowerFacto

Re

Where; 22 QPS

The power factor correction of electrical loads is a problem common to all industrial companies. Every user which utilizes electrical power to obtain work in various forms continuously asks the mains to supply a certain quantity of active power, together with reactive power. This reactive power is not transformed or used by the user, but the electricity supply company is forced to produce it, using generators, wires to carry and distribute it, through transformers and switching gears.

Power factor correction reduces the Joule losses of the transformers and the cables upstream of the installation point; reduction in losses, transmitted power being equal, is greater the lower the power factor value before applying the power factor correction.

The capacitor provides the necessary leading current (-ve Q) which results in reduce line current flowing in the system. The amount of reactive power needed is given by the following formula.

)tan(tan 21PQC

2V

QC

221 )tan(tan

V

PC

Where,

1tan = tan component of initial power factor

2tan = tan component of improved power factor



- 17-

Applying a star or delta-connected (three-phase load) group of three capacitors of suitable capacity in parallel to the resistive-inductive load terminals, the capacitive current Ic absorbed by them, which is in leading quadrature compared to the voltage Vt, opposes the component in lagging quadrature IL reducing it to I1 or even annulling it, with consequent decrease in the circulating line current, which takes on the value IR; the best situation is obtained when IC = IL and I is therefore reduced to the only in-phase component IR.

Using the above relations we can show that

CCY *3

Star connected and Delta connected capacitors, both have advantages/disadvantages too.

PROCEDURE:



- 18-

Delta Connected Capacitor Banks (Module AZ-191b):

A 2 F three-phase capacitor bank.

B 4 F three-phase capacitor bank.

L1-L2-L3 Three-phase capacitor bank input terminals, (delta connected three capacitors with voltage rating 450 V~).

C 3 single-phase inductors with rated current 1A and inductance of 100 mH.

D 3 x 100 k

2W resistances.

Resistive Load Bank (Module RL-2/EV):

R = 360

V = 220V I = 0.6A P = 132W R = 180

V = 220V I = 1.2A P = 264W R = 90

V = 220V I = 2.4A P = 528W.

Inductive Load Bank (Module IL-2/EV):

Z = 720

L = 2.3H V = 220V

f =50Hz I = 0.3A Pa = 66VA Z = 360

L =1.15H V = 220V

f =50Hz I= 0.6A Pa = 132VA Z = 180

L =0.58H V = 220V

f =50Hz I =1.2A Pa = 264VA



- 19-

OBSERVATIONS:

Follow the connections shown in figure below and fill up the table:

Load Combination

Active Power

Reactive Power

Apparent Power

Initial Power Factor

P.F Correction Using 3 x 2µF

P.F Correction Using 3 x 4µF

New Power Factor

New Line

Current

New Power Factor

New Line

Current

RESULT

The method of power factor correction has fully understood.

Electrical Power Distribution & Utilization Lab Session 07(a)


- 20-

LAB SESSION 07(a) Introduction to Lighting design software Calculux

OBJECTIVE

To become familiar with the basic environment of lighting design software

Calculux

THEORY

This Lab session will introduce the main feature of lighting design software and with the environment of Calculux. Calculux Indoor is a software tool which helps lighting designers in selecting and evaluating lighting systems for offices and industrial applications.

What can you do with Calculux Indoor?

Perform lighting calculations (including direct, indirect, total and average illuminance) within orthogonal rooms;

Predict financial implications including energy, investment, lamp and maintenance costs for different luminaire arrangements;

Select luminaires from an extensive Philips database or from specially formatted files for luminaires from other suppliers;

Specify room dimensions, luminaire types, maintenance factors, interreflection accuracy, calculation grids and calculation types;

Compile reports displaying results in text and graphical formats;

Support Switching modes and Light regulation factors;

The logical steps used for project specification save you time and effort, while the report facility gives you the opportunity to keep permanent records of the results.

Installing the program In order to install Calculux correctly, please stop all other applications before starting the installation.

To install the program: 1. Start Windows. 2. Connect the USB to your USB port [Let suppose drive (K:) of your computer]. 3. Follow the path K:\Calculux 4. Run the setup in the Indoor5.0b 5. Follow the instructions on screen.

Installing the database 1. Here in the folder DB, there is a database of Philips Luminaries 2. Install the database from the DB folder.

Environment of Calculux Indoor Software

When you start Calculux, the Calculux main window is displayed. This window always contains the menu bar, and if selected, it may also contain a tool bar and/or status line. When a project file is open and data has been entered, a 2D top view or 3D layout is shown.



- 21-

The menu bar contains the following menus:

1. File 2. Data 3. Calculation 4.Report 5. Finance 6. View 7. Options 8. Window 9. Help

Before Starting your First Project:

Installation of Calculux Indoor has been successful;

Vignettes have been installed;

Phillum files have been installed;

Database has been installed.

Before you start 'My First Project' first you should check the default settings of Calculux.

Checking the default settings

For 'First Project' you are going to check the following default settings:

Environment (options) (default settings concerning the program environment)

Report Setup Defaults (default settings concerning the contents and layout of the report)

Calculation Presentation Defaults (default settings concerning the Calculation Presentation)

Environment Select Environment from the Options menu.

Select the Directories tab. Check the directory settings of the Project files, Phillum files and Vignette files.

Select the Database tab. Check the directory settings of the Database files.

Click OK to return to the Main View. The Environment Options only have to be set after installing Calculux.

Report Setup Defaults Select Report Setup Defaults from the Options menu.

Select the Contents tab. In the Included box, select the chapters to be included in the report.

In the Presentation Forms box, select the presentation forms of the calculation presentation result views. Select Textual Table, Iso Contour,Filled Iso Contour

Select the Layout tab. In the Project Luminaire Information box, select in which way the luminaire luminous intensity information is to be shown.



- 22-

Select Show Polar Diagram

In the Installation Data box, select which elements are to be displayed in chapter 'Installation Data' of the report.

Select Show Aiming Angles

In the General box, select which additional information is to be displayed and in which language the report is to be created.

Click OK to return to the Main View.

Calculation Presentation Defaults Select Calculation Presentation Defaults from the Options menu.

Select the Presentation Forms tab. In this tab you can select the elements to be displayed in the calculation presentation result views. Select Textual Table, Iso Contour, Filled Iso Contour

Select the General tab.

In the Show box, select the elements to be displayed by default in the calculation presentation and report. Select Luminaires, Luminaire Code, Luminaire Legend, Drawings,Fill Color Legend, Room,Connected Field,Connected Grid

In the Iso Contour Method box, select which Iso Contour Method will be used by default for the calculation presentation.

Select Relative

Select the Scaling tab.

In the Minimum Report Scale box. Select 10

In the Sizing box, select the default sizing of the calculation presentation result views, select:

Zoomed Relative to Grid: Factor 1.000

By setting the above scaling, the size of the defined objects in the calculation presentation result overviews will be based on the size of the grid and the field. The size is determined by the 'Zoom Factor'.

Click OK to return to the Main View.

Now start your first project.

Electrical Power Distribution & Utilization Lab session 07(b)


- 23-

LAB SESSION 07(b)

Your First Project on lighting design using CALCULUX

OBJECTIVE

First Task of First project: Design a general lighting scheme of an office using CALCULUX. This will be your first task of this Lab.

The details are as under: Room Specifications

Room dimensions Width 3.50 m Length 5.60 m Height 2.70 m Working Plane Height 0.80 m

Reflections Ceiling 0.50 Walls 0.30 Floor 0.10

Position (of Left Front side of the room) X = 0.0 Y =0.0

Required illuminance level

General lighting 300 lux on working plane

Luminaire Specifications

Luminaire type TBS600/135 C7-60 Lamp type TL5 35W

Project Maintenance Factor 0.80

AA

AA

Fig: 1st Task



- 24-

Second Task of the First Project:

Let suppose there is a window in the back wall of the room, two luminaries of the Room Block arrangement have to be moved.

Add a table in the center of the room & write text on table TABLE .

table

AA

AA

Fig: 2nd Task

OBSERVATION:

Attach the Self generated Report with each task.

In each report following details should be there 1) Title Page 2) Table of Contents 3) Top project overview 4) Summary 5) Luminaries Details 6) Calculation Results

a) Filled ISO Contour

INSTRUCTION:

All the observation reports should be maintained in a separate file, do not staple the report with the workbook.

Electrical Power Distribution & Utilization Lab session 08(a)


- 25-

LAB SESSION 08 (a)

Your Second Project on lighting design using CALCULUX

OBJECTIVE

First Task of Second Project: The purpose of this lab is to measure the LUX level on the given working plane. This will be your first task of this Lab.

The constructional details are as under: Room Specifications



Position (of Left Front side of the room) X= 0.0 Y = 0.0

Illuminance level

To be measured

Luminaire Specifications

Luminaire type Lamp Type Color FBS331/218 M6 2xPL-L18W 840 TBS300/236 M1 2XTL-D36W 840

Project Maintenance Factor 0.80

Luminaires Location

Red Lamps (12 in Number) Spacing X- Spacing = 1.2m Y- Spacing = 1.6m Position X=1.20 Y=1.60 Z=3.66

Blue Lamps (20 in Number) Spacing X- Spacing = 1.5m Y- Spacing = 1.6m Position X=1.45 Y=2.20 Z=3.66



- 26-

-3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10X(m)

-0.5

00.

51

1.5

22.

53

3.5

44.

55

5.5

66.

57

7.5

8Y

(m)

AAAAA

AAAAA

AAAAA

AAAAA

BBBB

BBBB

BBBB

Second task of Second Project: In your second task

1. Group the luminaries in three separate blocks. 2. Make rectangles. 3. Make two separate grids, one for working plane & one for Table. 4. Now calculate the results. 5. Generate & Print the report. 6. Save the project.



- 27-

-4 -3 -2 -1 0 1 2 3 4 5 6 7 8X(m)

01

23

45

67

Y(m

)

Table 2

Table 1

BBBB

BBBB

BBBB

BBBB

AAAAAAA

AAAAAAA

OBSERVATION:

Attach the Self Generated Report with each task of the Project.



INSTRUCTION: All the observation reports should be maintained in a separate file, do not staple with the workbook.



- 28-

LAB SESSION 08(b)

Third Project on lighting design using CALCULUX

OBJECTIVE:

Design a task and accent lighting for an office.

The constructional details of the office are as under:

Room Specifications



Position (of Left Front side of the room) X 0.0 Y 0.0

Luminaries Used

TBS600/135 C7-60 MASTERLINE PLUS 20W 24D [13672]

Project Maintenance Factor

0.80



- 29-

-4 -3.5 -3 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 6 6.5 7X(m)

-0.5

00.

51

1.5

22.

53

3.5

44.

55

5.5

6Y

(m)

OBSERVATION:

Attach the Self Generated Report with each task of the Project.



INSTRUCTION: All the observation reports should be maintained in a separate file, do not staple with the workbook.



- 30-

LAB SESSION 09 Luminescence

OBJECTIVE

Verifying the Inverse Square Law and compare the difference in output luminescence of incandescent, fluorescent and compact fluorescent lamps.

APPARATUS

A wooden board

Connecting wires

Fluorescent Light

Incandescent Light

LUX Meter

TYPES OF LAMPS

INVERSE SQUARE LAW

The inverse-square law, which states that the illuminance at a point on a surface perpendicular to the light ray is equal to the luminous intensity of the source at that point divided by the square of the distance between the source and the point of calculation.

2D

IE

Where:

E = Illuminance in footcandles I = Luminous intensity in candles D = Distance in feet between the source and the point of calculation

INCANDESCENT LIGHT BULBS Incandescent light bulbs consist of a glass enclosure (the envelope, or bulb) which is filled with an inert gas to reduce evaporation of the filament. Inside the bulb is a filament of tungsten wire, through which an electric current is passed. The current heats the filament to an extremely high temperature (typically 2000 K to 3300 K depending on the filament type, shape, size, and amount of current passed through). The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off in the near-infrared wavelengths.



- 31-

Figure: Types of Incandescent Lamps

FLOURESCENT TUBE LIGHT A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light.

Compared with incandescent lamps, fluorescent lamps use less power for the same amount of light, generally last longer, but are bulkier, more complex, and more expensive than a comparable incandescent lamp.

Figure: Types of Fluorescent Lamps



- 32-

COMPACT FLOURESCENT LIGHTS A compact fluorescent lamp (CFL), also known as a compact fluorescent light bulb (or less commonly as a compact fluorescent tube [CFT]), is a type of fluorescent lamp. Many CFLs are designed to replace an incandescent lamp and can fit in the existing light fixtures formerly used for incandescent.

Compared to general service incandescent lamps giving the same amount of visible light, CFLs use less power and have a longer rated life, but generally have a higher purchase price.

PROCDUERE & CALCULATIONS

Place different lamps on the wooden board & calculate the LUX level at different point (Approx Results only due to some unavoidable problems).

S. No.

Type of Lamp Distance from

the source LUX

1 Incandescent 2

3 1

Fluorescent Lamp 2 3 1

Compact Fluorescent Lamp

2 3

RESULT

On wooden board, make the circuitry of Fluorescent tube.

EXERCISE

Draw the circuit diagram of a fluorescent lamp showing fluorescent tube, ballast & starter.



- 33-

LAB SESSION 10

Calculating the Total Cost in a Residential and

Commercial or Industrial Bill.

OBJECTIVE

You are given an Industrial or commercial Bill

Calculate the total energy cost of the utility bill.

Explain the terms used in the bill

Perform Exercise in the end of the Lab Session

Theory:

The rates of utility companies are based upon the following guidelines: 1. The amount of energy consumed [kW.h] 2. The demand rate at which energy is consumed [kW] 3. The power factor of the load.

The amount of energy consumed is measured by Energy meter and the demand of the system during the demand interval is measured by Demand meter.

What is The Difference Between Demand and Consumption?

Demand is how much power you require at a single point in time, measured in kilowatts (kW).

Consumption is how much energy you use over a period of time, measured in kilowatt-hours (kWh).

Example: assume ten lights are turned on each with a 100-watt bulb. To accomplish this, you must draw - or demand - 1,000 watts, or 1 kW of electricity from the power grid. If you leave all ten lights on for two hours, you would consume 2 kWh of electricity.

Demand Measurement

Demand varies by customer and month. To record demand, a special meter tracks the flow of electricity to a facility over a period of time, usually 30-minute intervals.

Over the course of a month, the 30-minute interval with the highest demand is recorded and reflected on a monthly bill.

Minimum Charges

means a charge to recover the costs for providing customer service to consumers even if no energy is consumed during the month.

Fixed Charges

means the part of sale rate in a two-part tariff to be recovered on the basis of Billing Demand in kilowatt on monthly basis.

Variable Charge

means the sale rate per kilowatt-hour (kWh) as a single rate or part of a two-part tariff applicable to the actual kWh consumed by the consumer during a billing period.

Maximum Demand

where applicable , means the maximum of the demand obtained in any month measured over successive periods each of 30 minutes duration.



- 34-

Sanctioned Load

where applicable means the installed load in kilowatt as applied for by the

consumer and allowed/authorized by the Company for usage by the consumer.

Power Factor

shall be to the ratio of kWh to KVAh recorded during the month or the ratio of

kWh to the square root of sum of square of kWh and kVARh,.

Formulae to be used:

1. Energy Charges (Rs) = No. of Units x energy charges (Rs/kWh)

2. Fuel Adjustment Charges (Rs) = No. of Units x energy charges (Rs/kWh)

3. Fixed Charges (Rs)

If MXD>50% of connected load

then Fix Charges (Rs) = Fix charges rates x MXD

If MXD<50% of connected load

then Fix Charges (Rs) = Fix charges rates x 50% of connected load

4. Additional Surcharge

Additional Surcharge (Rs) = No. of Units x Additional surcharge (Rs/kWh)

5. Income Tax

Applicable on Taxable Amount

Taxable Amount = Energy Charges + Fuel Adjustment Charges + Additional Surcharge + Fixed Charges + Electricty Duty + Meter Rent + P.f Penalty

6. Sales Tax

Sales Tax = some percent of Taxable amount (See Tarrifs)



- 35-

EXERCISE:

Attach the bill here:



- 36-

Calculations: _____________________________________________________________________________________________

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- 37-

LAB SESSION 11

Diesel Generating Set OBJECTIVE

To study the various components of a Diesel Generating Set

THEORY

It is common practice to provide the standby emergency source of supply at all important installations such as large factories, railways, airports & other essential services. This is usually achieved with the use of a captive Diesel Generator Set (DG Set).

Main Components of A Diesel Generating Set

DG Set comprises of three main parts.

Engine This is the main prime mover (PM) for the generator and may be a gas, petrol or diesel engine, depending upon the availability of fuel. In this LAB we will discuss the Diesel generating Set, being used more commonly for captive power generation.

The control of power output is obtained through this PM only. It has a drooping characteristic.

Governor This senses the speed of the machine and performs extremely fast and accurate adjustments in the fuel supply to the PM. In turn it regulates the speed and output of the PM within predefined limits, depending upon the droop of the PM. The governor may be a mechanical (manual), hydraulic or electronic (automatic) device.

Generator Generator is responsible for changing engine power (hp or kW) into electrical power (kVA). They also must satisfy high magnetizing current draws (kVAR) of electrical equipment.

NEMA suggests 0.8pf for standard generator.

Engine & Generator Sizing Engines are sized according to the actual power in kW required to meet the need of the facility. The generator on the other hand, must be capable of handling the maximum apparent power which is measured in kVA. Thus engine provide power (kW) and frequency control, generator influence kVA and voltage control.



- 38-

Fig: A Complete DG Set

Fig: Auxiliary Fuel Tank



- 39-

Fig: A front View of a Diesel Generating Set

Fig: Air Ducting

Fig: Batteries & Battery Charger



- 40-

Fig: Vibration Isolator

Fig: Batteries

EXERCISE:

Household Equipments Ratings:

Fill the following table;

S. No.

Item Rating (kW) 1 Ceiling Fan 2 Computer Monitor (Size= inches) 3 Refrigerator 4 Split AC (1 ton) 5 Split AC (1.5 ton) 6 Window Type Split AC (1 ton) 7 Window Type Split AC (1.5 ton) 8 Washing Machine 9 Electric Iron

10 Microwave Oven 11 Television (Size = inches) 12 Available Fluorescent Tubes 13 Available CFL 14 Printer (Laser jet or dot matrix) 15 Tape Recorder

This chart is very useful in calculating the size of the generator required for your home. Question: Explain the following parts or terms of Diesel Generating Set:

1. Radiators 2. Fuel Tank & Base Frame 3. Canopy 4. Main Tank & Auxiliary Tank 5. Silencer & Exhaust System 6. Drain Valve & Shut-off Valve 7. Shock Vibrators 8. BHP 9. Ducting 10. Standby, Prime & Continuous Ratings 11. Batteries & Battery Chargers 12. Generator Amperage 13. Crank 14. Blower Fan



- 41-

LAB SESSION 12 Home Electrical Wiring

OBJECTIVE

To make connections in home electrical wiring from services main to different distribution boards and electrical points for appliances in a room.

APPARATUS

A large wooden board

Kilo Watt-hour Meter

Wires & Cables

Switches & Sockets

Bulbs & Fans

THEORY

Designing the home electrical wiring needs careful consideration because of safety. For wiring in residential buildings or industrial buildings, wiring layout should be first prepared on the drawing board.

The number of light and power points in a building is determined not only by its size, but is also a matter of individual preference especially in the case of residential buildings and as such the owner should be consulted for this.

The number of outlets should be adequate to ensure convenient hooking up of the various electric operated gadgets & appliances. Minimum four outlets one per wall should be provided in each room. Lamps & motors should normally be wires on different circuits.

Figure: Typical Domestic Intake Arrangement



- 42-

Yellow Phase Blue Phase

EXERCISE

Make connection of the three phase watt hour meter with the service main and distribute the three-phase incoming service main & neural wire to different distribution boards & electrical points (for appliances) in different rooms of the house.

Select cables for them.

Measure the total energy.

Also draw the circuit diagram on AUTOCAD using the standard symbols of switch fan bulb etc.

R+N

Y+N B+N

In Room 1,2,3 &4 1 Tube Light is there on any one of the walls. 1 Ceiling fan is there. 1 DB is there (with three switches & one socket).

In each washroom, Only one light is there, controlled from outside the washroom.

Red Phase is feeding Room 1 & Room 2; Yellow Phase is feeding Room 3, while Blue Phase is feeding Room 4.

ROOM NO. 01

KWh Meter

R

Y

B N Wash

Room

ROOM NO. 02

Wash Room

ROOM NO. 03

Wash Room

ROOM NO. 04

Wash Room



- 43-

On AutoCAD/Microsoft Visio, draw the SLD of your house showing Electrical & Civil work (Stairs, Rooms, Kitchen etc).

Make an extension board with & without fuse with three sockets & one switch in it and show the wiring diagram with color pencil.

Phase Neutral

Phase Neutral

1 2 3

FUSE SWITCH SOCKETS

5A

1 2 3

SWITCH SOCKETS



- 44-

LAB SESSION 13

Earthing OBJECTIVE

To measure Earthing Resistance and Soil resistivity.

APPARATUS

Earth Resistance Tester

Hammer

Measuring Tape

THEORY

Earthing provides protection to personnel and equipment by ensuring operation of protective control gear and isolation of the faulted circuit in the following cases.

Insulation puncture or failure

Breakdown of insulation between primary & secondary windings of a transformer.

Lighting stroke

Ensuring low earth resistance is important in earthing process. In case where protection against the faulted list is provided by mean of fuse or a circuit breaker, the total resistance of the earth path must be low enough to enable the operation of the protective device.

The earth electrode resistance depends upon the electrical resistivity of the soil in which the electrode is installed, which in turn is determined by the following factors:

1. Nature of soil 2. Extent of moisture 3. Presence of suitable salts dissolved in moisture.

TYPES OF EARTH ELECTRODES

Rod & Pipe Electrodes

Plate Electrodes

Strip or Round Conductor Electrodes

Plate Electrodes: Plate electrodes consist of copper, cast iron or steel plate. The minimum thickness of plate is recommended as

For cast iron - 12mm

For GI or steel - 6.3mm

For Copper - 3.15mm And size not less than 600mm x 600mm.



- 45-

Figure: A typical layout of Plate Electrode

The approximate resistance to ground in a uniform soil can be expressed by

AR

24

where p = resistivity of soil, considered uniform in m. A= area of each side of the plate in m2

Rod & Pipe Electrodes: This type of earthing is more suited for a soil possessing high resistivity and the electrode is required to be longer & driven deeper into the soil to obtain a lower resistance to ground.

The diameter, thickness and length of the pipe is recommended as follows:

Cast iron (CI) pipes - 100mm (internal diameter), 2.5 to 3 m (long), 13mm thick.

MS pipes - 38 to 50mm (internal diameter), 2.5 to 3 m (long), 13mm thick

Copper -13,16 or 19mm diameter, 1.22 to 2.44m long.



- 46-

Figure: A typical arrangement of pipe electrode grounding In this case, the approximate resistance to ground in a uniform soil can be expressed by:

18

ln**2

100

d

l

LR

where R= Resistance in

l = length of pipe in cm d = internal diameter of pipe in cm Resistivity of Soil: Type of soil Average resistivity( )

1. Wet organic soil 10 2. Moist Soil 100 3. Dry Soil 1000 4. Bed rock 10000

It has been found that the resistivity of the soil can be reduces by a chemical treatment with the following salts.

Normal Salt (NaCl) and a mixture of salt & soft coke.

MgSO4

CuSO4

Economical and most commonly used salts



- 47-

CaCl2

Na2CO3

Usually the mixture of NaNo3 + sea salt + coal is used in the ratio of 1:3:5

MEASURING THE SOIL RESISTIVITY:

Soil resistivity is the key factor that determines what the resistance of a grounding electrode will be, and to what depth it must be driven to obtain low ground resistance. The resistivity of the soil varies widely throughout the world and changes seasonally. Soil resistivity is determined largely by its content of electrolytes, which consist of moisture, minerals and dissolved salts. A dry soil has high resistivity if it contains no soluble salts (Figuer 1).

4 POLE METHOD

A simple way to measure the resistivity of soil is a four-pin method in which four probes are drilled into the ground along a straight line at equal distances a and depth b. Then a voltage V is applied to the two inner probes and a current, If, is measured in the two outer probes (Figure 22.16). This test can also be conducted with the help of a ground tester as discussed in Section 22.3, which normally also has a provision for this test.

The formula for measuring soil resistivity is given below;

For accurate results 20

ab

Where: a = distance between the electrodes in centimeters

More common salts



- 48-

b = electrode depth in centimeters = Soil resistivity (ohm-cm)

Since generally

a >> b (for accurate results keep 20

ab

)

gaR2

For Example After inspection, the area investigated has been narrowed down to a plot of ground approximately 75 square feet (7 m2). Assume that you need to determine the resistivity at a depth of 15 feet (450 cm). The distance A between the electrodes must then be equivalent to the depth at which average resistivity is to be determined (15 ft, or 450 cm). Using the more simplified Wenner formula (

gaR2 ), the electrode depth must then be 1/20th of

the electrode spacing or 8-7/8 (22.5 cm).

For example, if the reading is R = 15 = Soil resistivity (ohm-cm) = 6.28 x 15 x 450 = 42,390 -cm

OBSERVATION:

MEASURING SOIL RESISTIVITY Length and Resistance of Wires

Red (ft)

Blue (ft)

Green (ft)

Black (ft)

Test 1: Spacing Between the Rods = S = (ft) Depth of Rods = 1/20 of S = (cm) Value of Resistance Measured: (ft) Calculated Value of Resistivity:





- 49-

MEASURING THE GROUND RESISTANCE:

The resistance of a grounding station can be measured with the help of a ground tester, which generates a constant voltage for accurate measurement. The tester has two potential and one current probe. The procedure of measurement is illustrated in Figure.

3 POLE METHOD

The method for measuring earthing resistance is given below. One of the potential probes A is drilled into the ground at about 15 m from the grounding station G, whose resistance is to be measured. The second probe B is placed between the two. The current lead of the meter is connected to the grounding station. The meter will indicate some resistance, which may be noted. Two more readings are also taken by shifting the centre probe B by almost 3 m on either side of the original location. For an accurate due of the ground resistance, the values obtained must be same. If they are not, the probe B is still within the resistance area of the grounding station G. Shift away probe A by another 6 m or so and place probe B between G and A, and repeat the test. If the three readings are now the same, consider this as the actual ground resistance of station G, otherwise shift probe A farther away until a constant reading is obtained.

Effect of Ground Electrode Size and Depth on Resistance

Size: Increasing the diameter of the rod does not materially reduce its resistance. Doubling the diameter reduces resistance by less than 10%.

Depth: As a ground rod is driven deeper into the earth, its resistance is substantially reduced. In general, doubling the r od length reduces the resistance by an additional 40% (Figure 11). The NEC (1987, 250-83-3) requires a minimum of 8 ft (2.4 m) to be in contact with the soil. The most common is a 10 ft (3 m) cylindrical rod which meets the NEC code. A minimum diameter of 5/8 inch (1.59 cm) is required for steel rods and 1/2 inch (1.27 cm) for copper or copper clad steel rods (NEC 1987, 250-83-2). Minimum practical diameters for driving limitations for 10 ft (3 m) rods are:

1/2 inch (1.27 cm) in average soil 5/8 inch (1.59 cm) in moist soil 3/4 inch (1.91 cm) in hard soil or more than 10 ft driving depths

Measuring the ground resistance with the help of a ground tester

Measuring the ground resistance with the help of an ammeter and a voltmeter



- 50-

MEASURING EARTH RESISTANCE Length and Resistance of Wires

Red (ft)

Blue (ft)

Green (ft)

Black (ft)

Test 1: Depth of Rod =

(cm)

Distance of Current Electrode = (ft)

Color of Wire Used=

Distance of Voltage Electrode = (ft)

Color of Wire Used=

Value of Resistance Measured:

Test 2: Depth of Rod = (cm)


Color of Wire Used=


Color of Wire Used=


Test 3: Depth of Rod = (cm)


Color of Wire Used=


Color of Wire Used=


RESULT

Earthing process has fully understood.

electrical power distribution & utilization - ned university

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