ceb training report 3

PREFACE

This report is based on the in-plant training of the first six month of National Diploma in

Technology- University of Moratuwa.

My training place was Sri Lanka Railway workshop Ratmalana. They are doing locomotive

repairing and maintenance and manufacture locomotive parts. I was in four electrical workshops.

When I was there I could be able to get vast knowledge. Mainly locomotive and industrial electrical

works. This report gives a brief description of working experience with theoretical things which I

got in my training period.

This report contains four chapters. The organizational structure of the Sri Lanka Railway

Department is described as the introduction in first chapter. Second chapter describes my

experience I had gained during my training period. Then I was added the suggestions I have made

to maximize the efficiency of the workshops and the conclusion which includes a summary of the

training period as the third chapter. Finally the leave record form, training schedule and annex G are

added as in chapter four.

1

ACKNOWLEDGEMENT

My special thank must go to,

All of the academic staff members of Department of Electrical Engineering Technology of

ITUM for afforded with theoretical knowledge in myself and my colleagues.

Mr.R.Perera, Training Engineer of Industrial Training Division of ITUM

Staff of National Apprentice & Industrial Training Authority (NAITA)

Mr.Budhdhadasa, Training Operation Manager of Ceylon electricity board.

And also I thank to the Engineers, Superintends and other staff members in CEB, who helped us sharing their knowledge.

All of the workers and technicians who supported to me for completed my training period

successfully.

W.L.Mahesh

Instutute of Technology

University of Moratuwa.

2

CONTENTS

Preface..................................................................................................................................... i

Acknowledgement .................................................................................................................. ii

Index ....................................................................................................................................... iv

CHAPTER 1

Introduction …………………………………………………………………..…….……….. 05

CHAPTER 2

Grid Substation-Horana......................................................................................................... .. 07

Waskaduwa Substation...................................................................................... 08

CHAPTER 3

Construction Branch.................................................................................................................. 10

CHAPTER 4

Meter testing laboratory .......................................................................................................... 13

CHAPTER 5

Projects and Heavy maintenance .........................................................................…............... 16

CHAPTER 6

Tariff & Billing………………………………………………….........…………….............. 20

Experiences at area office.................................................................................................... 22

CHAPTER 7

Conclusion …………………………………………………...…………............................... 23

CHAPTER 8

Annex D........................................................................................................................ 24

Annex F......................................................................................................................... 25

Annex G........................................................................................................................ 26

3

INDEX

Fig 1: Auto Recloser ……………………………………..………………………......................... 08

Fig 2: Signal trap ………………………………………………………………….....…………... 09

Fig 3: surge arrester ……………………………………………………………............................ 09

Fig 4: pin type insulator …………………………………………………………………..……... 10

Fig 5: Suspension type insulator …………………………………………………………....…… 11

Fig 6 Aerial bundled conductor ……………………………………............................................. 12

Fig 7: single-phase meter test rack and bench………………………………………………….. 14

Fig 8types of towers……………………………………………………………………................ 18

4

CHAPTER 01

INTRODUCTION

Ceylon Electricity Board, which is commonly known as the CEB was established by the Ceylon

Electricity Board act in 1969 under the Ministry of Irrigation and Power. Later on, the CEB was

transferred to the Ministry of energy and power. Currently this institute is governed by the Ceylon

Electricity Board act 1969 and Sri Lanka Electricity act 2009. The CEB has divided into three

divisions; Generation, transmission and Distribution. Currently, the license for generation and

distribution are issued for IPPs as well as the CEB and CEB is the only one who is having the

license for transmission.

Vision

“Be an internationally recognized efficient utility providing high quality service to all its stake

holders.”

Mission

“To provide reliable quality electricity to the entire nation at internationally competitive prices

effectively and efficiently through a meaningful partnership with skilled and motivated employees

using appropriate state-of-the-art technology for the socio economic development of the country in

an economically sustainable manner while meeting acceptable environment standards”

Present Performances of CEB

CEB is the largest organization related to the power sector in Sri Lanka and the main controller of

the power sector. 74% of the installed capacity in Sri Lanka is owned by CEB. And the current total

capacity which is owned by CEB is about 1902.1MW. And also, it serves more than 90% of area in

Sri Lanka through the transmission and distribution lines owned by CEB. Due to the large size and

the complexity of the organization, even though the organizational structure is well structured, the

management had become a problem. There are many inefficiency in CEB and it was categorized as

an institute, run in a loss state. To overcome this problem and to generate reliable operation out of

CEB, a restructuring for CEB was proposed. According to that, the CEB is supposed to divide into

5

three individual sectors and privatize them was proposed. But, due to the criticisms of the trade

unions, the proposal was failed from the parliament.

Weaknesses of CEB

CEB is an organization which is operated under the Sri Lanka Government. So the rights of the

employees are significantly strong. So the employees, who are not taking a part of the critical

decision makings and the critical issues, are acted in an unproductive manner. This makes CEB a

loss counting organization. And also, because of CEB is operated under the government, some

important decisions like building plants are taken through the government. So the control of the

CEB is gone out of its hand, sometimes to the people who are not having the proper understanding

of the field’s important areas. This makes the operation difficult to CEB.

Usefulness to the society

The electricity, as said above, is an essential service. Manipulating such a sector in a reliable

manner is a great social service to the country. Even though the distribution ends are having come

problems, as a macro scale picture, CEB provides a quality vice very good service through the

generation, transmission and satisfactory service through distribution. The staff in key positions of

the institute are always try to conduct a safe and reliable service to the country. As an example, the

number of blackouts is a minimum and the voltages in the transmission ends are usually kept within

the range.

6

CHAPTER 2

Grid Substation-Horana

We visit to Horana grid substation within our area office training period. Horana grid is placed

between Pannipitiya and Mathugama grids. Its high voltage side is a outdoor type and low voltage

side is a indoor system. There is a diesel power plant near to the grid and they join to the system

across the Grid. Grid has eight 33kv feeders.

Whole system is fully automatic and computer control system. Control system works using DC

current. It has an Alkaline battery bank for that purpose. Grid has two 31500KVA transformers.

SF6 circuit brakers are used.

Name plate data of step down transformer

T/F with on load tapping

2004/3 phase/31500 kva

Positions -3

Short circuit current – 1.7 kA

Oil temp – 50 C

Mask of Oil – 11.5 t

Total mask – 55 t

This is a indoor type fully protected, on load tapping transformer. A Zigzag transformer is used for

earthling system of the transformer.

Waskaduwa Substation

It is a 33kv, 11kv step down substation. It has two 33kv incoming lines and four 11kv feeders. 33kv

side is indoor system and 11kv side is a indoor system. It has two 500kva step-down transformers

and its cooling system is ONAN. Oil and vacuum cct breakers used. It has a remote controlling

system using DC , but it is not Computerize system like Horana Grid.

7

We observed special components units in these substations. They are used for various types of

purposes.

CT/PT Unit

The main purpose of the this unit is reduce current and voltage levels such as measurable to many

kind of electrical equipment such as measuring meters. Two lines of three phases are gone through

the unit while taking these lines as the primary of the current transformers. The secondary of the CT

will reduce the current to be measurable while voltage is also reduced by a voltage transformer.

Then measuring devices can be measured the load. The other phase of 3 phase line is kept as a

reference since CT/PT unit uses two watt meter method to measure the power.

Auto Reclosers & Sectionalizers

Auto reclosers have the facility of to sense over current conditions on phase fault and earth fault,

and interrupt such fault currents and to re-energize the line by reclosing automatically after a pre

determined time delay. If a fault is permanent, the reclose will lock open after a present number of

operations and isolate the faulty sections .Series coils inside the recloser tank sense fault conditions

and trip the recloser. Closing energy is provided by a high voltage closing solenoid which

simultaneously charges the opening spring in preparation for a tripping operation. The units are

capable of manual operation from ground level by means of an insulated fiberglass operating stick.

Usually in CEB, auto reclosers are mounted in the beginning of a feeder. But auto reclosers can be

mounted on a pole in the middle of a feeder.

Figure 1– Auto Recloser (left) a sectionalizer (right)

8

Signal Trap

Figure 2 – Signal trap

It is a capacitive transformer device. It used to filter the information signal from the load line. That

info signal is different from 50Hz.

Surge arresters

Figure 3- surge arrester

Surge arresters are used for ground the exceed voltage because of lighting and short circuit

problems. When pass the rated voltage of it, it become a conductor and exceed voltage grounded

across it.

It has two main rated voltage type

MCOV- maximum continuous operation voltage

TOV- temporary over voltage

We look following things for selection of arrester for different places

System voltage

Line to ground voltage

Grounding info

Protection level

Energy capability

9

CHAPTER 3

CONSTRUCTION BRANCH AT RATHMALANA

Introduction with experience

We were assigned to the Panadura construction gang. The depot consists of an Electrical

Superintendent, and some technicians and laborers under him. These construction depots do the

estimation of projects planned by the planning branch and then do the construction. Some examples

are providing supply to the bulk consumers and terminations. At there we attend to constructing a

pole mounted substation in Cancer Hospital, Maharagama. We also studied about earthling of LV

and MV lines. We familiarized with Identification of construction materials, equipments and tools.

We studied about construction standards too.

Types of insulators

We saw two type of insulators mainly.

01. Pin type

The pin type is secured to the cross arm on the pole. There is a groove on the upper end of the

insulator for housing the conductor. The conductor passes through this groove and it is bound by

the annealed wire of the same material or steel binding wire.

The cross section of a pin type insulator is shown in follows figure

Figure 4- pin type insulator

10

02. Suspension type insulator

Figure 5 - suspension type insulator

Construction materials and tools

I saw used following materials and equipment in the construction branch. The materials used for

constructing a pole mounted substation and HV, MV and LV lines can be categorized as follows.

Materials used forLV,HV & MV lines

Materials used forSub station

1. Poles (RC/ PS/ W)2. Shackle insulators3. Pin Insulators4. Shackle cross arm5. Pin cross arm6. Stays & Struts7. D-brackets8. LT insulators9. Shackle straps10.Parallel groove clamps11.Bimetalic line tap12.Earth pipe13.MCCB14.Flat iron15.Channel iron/ Angle iron16.Thimbles17.Nuts & Bolts

1.Transformer 2.RC/ PS poles (10m/11m) 3.Danger boards 4.DDLO fuses (33/11 kv) 5.Lightning arrestors(33/11 kv) 6.Shackle insulators 7.Shackle cross arm 8.Pin insulators 9.Pin cross arm10.Stays complete11.Bimetalic clamps & line taps12.12"×6"G.I. Earth pipe13.PVC conductors (Al/Cu)14.Cable socket amps15.LT PVC cables16.MCCB/ Fuse switch disconnector17.Metal enclosure18.Cutouts T.P. & N19.Substation- package type20.Polyphase meter21.Cable tiles22.Bolts & Nuts

11

Most used LT conductor types

Fly- 7/3.40 mm

Wasp- 7/4.39 mm

AAAC 7/4.25mm

AAAC 7/3.10 mm

In HT

AAAC (ELM) 19/3.76mm

ACSR (Racoon) 7/4.09mm

Aerial bundled conductor

Figure 6- Aerial bundled conductor

There are two types use in CEB. First one is three phase 4 wire bundle and another type is five

conductor bundle.5th one is street lamp conductor. For identify those conductors separately, it has

different no of ribs on the cable insulator.

line conductor -70 squire mm

neutral conductor -54.6 squire mm

street lamp wire – 16 square mm

12

CHAPTER 4

METER TESTING LABORATORY AT PILIYANDALA

Introduction with experience

Energy metering at distribution level is a most important function in commercial aspects. Meters

are used where CEB sell power to customers/LECO as well as it buys power from private sector.

Therefore the accuracy of the meters is most important; Kiribathgoda Piliyandala Kolonnawa and

Kurunegala Meter Testing Laboratories has been established by CEB. During our time, the

laboratories do certain tests on various types of electrical meters before they are installed in houses,

factories or other places where the electrical energy is consumed. The objectives of these tests are

to confirm the proper operation of the various parts of the meter, to set the percentage accuracy

according to the CEB standards etc. Apart from these tests, inspecting maximum demand and 3-

phase energy meters installed in factories and other places, carryout tests on domestic electrical

energy meters, which have been found to be defective, are also take place.

When installed meter for 3-phase supply very import think is how to connected CT’s. S1, S2, P1,

P2, Must connected correct direction. For the 3-phase supply we connected three CT’s. when

connecting the direction is change one CT the meter reading lack 66% form correct reading.

We can saw this problem because the meters are installed by the depot some time they change

direction of CT’s These days CEB installed new poly phase meter for bulk consumer. About this

meter we discuss later.

We saw following duties they doing:

1. Test and calibrate meters before installing

2. Repair of electricity meters & again calibrate them.

3. Routing inspections

4. Inquiries on complaint

5. Install energy meters and maximum demand meters according to the relevant tariff

structures.

13

Single Phase Meter Tests

When testing new single-phase meters, first of all they are placed on the test bench and the links

between current and voltage coils are removed. The rated voltage is supplied for 30-45 minutes.

Then both rated voltage and maximum current (shown in name plate) are supplied for 4-5 minutes.

After that following tests are carried out.

1. Wiring

2. Heating

3. Quality test

4. Full Load Testing

5. Low load test

6. Power Factor Testing

7. Starting current test

8. Creep Test

9. Dial test

Figure 7- single-phase meter test rack and bench

Three phase meter test

I could observe calibration of three phase meter test bench by national weighting and measuring

authority. They use k2006, three phase comparator as equipment for this calibration. first we

measured meter temperature, relatively humidity, and atmospheric pressure. Then connect reference

meter and comparator to test bench and observed percentage error. We got readings with varying

current and power factor. Test bench gives 0.1 percentage error and comparator gives 0.01

percentage error.

14

Power factor test

This test is also known as inductive load test .It is given the base current with 0.5 power factor. Test

is done for 10 rev at tolerance 2%. Power factor adjustment is done to avoid error.

Maximum demand meter

This meter we observed at the places of bulk consumers. Normally they are charged with a two rate

tariff for total energy consumption and maximum demand. Old meters are mechanical type and

modern meters readings included all other types of energy measurements.

15

CHAPTER 5

HEAVY MAINTENANCE AND PROJECT PLANNING BRANCH

Introduction

The Medium Voltage in Electrical Power system is 33 and 11 kVs.. The heavy maintenance branch

of the CEB is responsible for the maintenance of the medium voltage lines, especially the 33kV, in

the whole country.

Main tasks carried out by the heavy maintenance branch, Piliyandala is;

Routine maintenance.

Restoration of supply after major breakdowns in 33kV lines or

Primary Subs.

This branch has divided its functions in to three;

Substation Maintenance

This is mainly the primary substation maintenance.

Line Maintenance

This can be further divided into Hot line (Live line) maintenance and Cold line maintenance

Project planning

Planning all the think before installed new tower line

16

There is a Chief Engineer who is in charge of the whole activities. Under him there are three

Electrical Engineers who look after the Line maintance, project and the Substation section. There

are three Electrical Superintendents under each of the three EEs.

Protection of a grid substation is necessary. Because consumers expect continuous supply in any

condition. Therefore to protect grid subs expensive equipments are used. There are two types

protection methods called main and back up protection. Classification of a grid sub protection can

be split into three areas..

Lines

Distance protection & differential protection Over current protection & earth fault protection

Transformers

Differential protection & restricted earth fault protection Over current protection & earth fault protection. Buchoze relay and differential relay is very important.

Switch and bus bars

Differential protection Earth fault protection

System earthing

Earthing associated with current carrying parts of the equipment is called system earthing. The

system security, reliability, performance, voltage substitution, all relied on the system earthing.

17

I saw various types of towers. Some have single circuit. Some have double circuit. But today not

build single circuit tower always build double circuit tower because reduces the cost and land. MV

and HV lines used these type of tower I saw.

Single circuit tower

Double circuit single earth tower Double circuit double earth tower

Figure 8- tower types

Line Route Selection procedure

Sketch the proposed line path on 1:50000 map or on satellite image.

Find the shortest path between the start and end

18

Collect information about lands and properties.

Design the path with minimum problems

Take side-side dimensions and all vertical heights.

Soil testing of tower location and select the foundation type.

Foundation types

A- Good soil

B- Bad soil

C- Water logged soil

D- Dust

Prepare,

E- Notice - to give information to people

D- Notice - Mark 10 m of two side of line and issue d notice, attend land dispute with AGA

when required

Stub

Stubs are tower legs. Stub setting is very important. We visited to do stub setting of one tower

at Ambalangoda. Whole tower structure balance depend on the stub. The stub parts adjust using

two angles. Those angles are depending on the tower type.

Stringing

Place all conductors

Use sag board or tension gauge

Use crimping tools

Fixing vibration dampers and arching horns

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CHAPTER 6

Tariff & Billing

In the present, LECO & CEB have the same tariff rates effects onwards 1st of November 2008. There are several tariff rates for the several categories of consumers. Basically 2 factors are considered for dividing the consumers among those categories. They are,

1. Estimated Ampere requirement of the consumer

2. Consumer’s purpose

The present tariff categories using in Sri Lanka are,

1. Domestic purpose

2. Religious purpose

3. General purpose

4. Industrial purpose

5. Hotel purpose

6. Street lighting

Basically CEB has a billing cycle of 30 days and revenue officers visit each and every consumer

and take the meter reading and submit the bill to the consumer.

Tariff categoryDomestic Purpose

Unit charge

(Rs/kWh)

Fixed charge(Rs/month)

up to 30 units per month

in excess of 30 and up to 60 units per month




above 600 units

3

4.7

7.5

16

25

30

60

90

120

180

240

240

20

In the present domestic and religious tariff schemes, there is a large amount of increasing in the bill,

when the 30 days consumption exceeds 90 units. This is a weak point of this tariff system. It must

be highlighted that above all consumption unit margins are defined for 30 days. In a case of

increasing of decreasing of a billing cycle therefore there won’t be harm to the consumer. As a

example if the revenue officer comes after a 33 days then the above tariff table will be flow rated as

below.

Flow rated domestic tariff table for 33 days

Comparison of Domestic tariff when exceeding 90 units for 30 days

For 90 units,

Cost For 0 -30 units = 3x30 = Rs.90.00

Cost For 30-60 units = 4.70x30 = Rs.141.00


Fix cost = Rs.120.00

Discount (as no of units<90) = Rs.30.00

Total bill = Rs.546.00

For 91 units,

Cost For 0 -30 units = 3x30 = Rs.90.00

21



Cost For 90-91 units = 16x1 = Rs.16.00

Fuel adjustment charge = 0.3x (90+141+225+16)

= Rs.141.60

Fix cost = Rs.180.00

Total bill = Rs.793.50

Hence we can see that there will be a price difference of Rs.247.50 between 90 units

and 91 units.

Experiences at area office

During the week we had the chance to attend the reconnection visit. In this, five disconnections ate

reconnected. When disconnecting a supply, the phase line is removed from the meter, and seals it.

When the approval for reconnection is given, the removed phase line is connected to the meter

again. If the disconnection is difficult due to the consumer matters, the line is disconnected from the

pole. The maintenance gang uses an identical tool for the gang, to seal the meters. After all the

works with the meter sealing, a docked is issued. And also, we had the chance to attend a service

maintenance visit. In this, we had the chance to attend two meter shifting, service wire replacement

and a meter box replacement. The MCB which is used instead of the fuse in CEB is used to protect

the meter. Therefore, it should be connected before the meter. But, what we observed is, connect

the MCB after the meter to prevent stealing the electricity from the MCB position. And also, the

service wire should be placed in a clearly visible manner, to the revenue officer. We too had the

chance to prepare connections of the meter box. Furthermore, the maintenance personals worked in

the on-load. They removed the conductor in the live wire for some length for the safety purposes.

They used the electricity in the phase for the drilling purposes of the walls.

22

CHAPTER 7

Conclusion

I’ve got a good opportunity to have my second compulsory session of industrial training in Ceylon

electricity board. CEB is the Sri Lanka’s major power distributor in Sri Lanka. During this valuable

period I was able to take so many experiences about the transmission, and distribution network of

Sri Lanka and I could be able to collect faculty of knowledge with in these six months of my

industrial training. Here I should mention that I was able to get a special opportunity to work

together technicians as well as engineers and share their knowledge and experiences. All of the

workers were really helpful to me by guiding to get working experience and educating me to get

knowledge about some are new for me. Also the resources that were available to me were very

satisfactory.

In my training session I not only gained the technical knowledge and also got the knowledge about

how to dealing with working environment, how to dealing with the officers & the workers, how to

maintaining the stocks in the workshops and their importance.

Those things gave me a really good training as an engineering undergraduate. Since CEB directly

deals with consumers, I could be able to get the knowledge about how to deal with them. But it

would be better if CEB would change their training schedule a little bit in order to get more

practical knowledge on technical side in the sites etc.

However I had a good training session at CEB with in my final industrial training. So, it helps me to

gain a better experience and work made my training valuable and successful.

23

CHAPTER 8

Annex D

LEAVE RECORD FORM

To be sent by registered post to Head of Industrial Training, Institute of Technology, University of Moratuwa after completing each six month period.

1. Name of Trainee: W.L.Mahesh

2. Industrial Training: 2 nd six months

(1st six months / 2nd six months)

3. Training Establishment: Ceylon Electricity Board

4. Leave Record

1st Month 2nd Month 3rd Month 4th Month 5th Month 6th Month

No. of days on Leave

5. Has the leave been approved by the Establishment: Yes

Date:

Signature of Trainee

Note: This is mainly for the information of ITUM and not to replace the standard leave application form, which has to be forwarded to the organization.

24

Annex F

TRAINING SCHEDULE

Name of Organization: Ceylon Electricity Board

Address of Organization / Worksite:

Trainee’s Name with Initials: W.L.Mahesh

Registration No.: 07/IT/EE/123

DivisionDept /Section

Areas of Training ReceivedAs per Training guidelines

Duration

Signature of Trainee: Date:

This is to certify that the trainee concerned received the training stated above.

Name of the Officer in Charge of Training:

Signature: Contact Telephone Number:

Annex G

25

CONFIDENTIAL

NATIONAL APPRENTICE AND INDUSTRIAL TRAINING AUTHORITY 1 ST SIX MONTHS / 2 ND SIX MONTHS ASSESSMENT OF N.D.T. APPRENTICE 2010

Place of Assessment: …………………………………. Date of Assessment: ………………...... …………………………………. Time: ………………….

Field: ………………………………………………………

Serial

No.

Name

Assessment element

Remarks

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Pro

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15 10 20 40 10 05 100

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

NAME OF EXAMINER DESIGNATION SIGNATURE

1.

2.

3.

4.

5.

26

ceb training report 3

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