Training report

INDUSTRIAL TRAINING REPORT
SHARJAH ELECTRICITY AND WATER AUTHORITY, UAE
Submitted in partial fulfilment of the requirements for the
award of the degree of
BACHELOR OF TECHNOLOGY
in
ELECTRICAL AND ELECTRONICS ENGINEERING
SUBMITTED BY
SHARON SAM KODUNTHARA
ST. JOSEPH'S COLLEGE OF ENGINEERING & TECHNOLOGY, PALAI.
DEPARTMENT OF ELECTRICAL & ELECTRONICS ENGINEERING
CHOONDACHERRY P. O., KOTTAYAM - 686579
NOVEMBER 2016

INDUSTRIAL TRAINING REPORT
SHARJAH ELECTRICITY AND WATER AUTHORITY, UAE
Submitted in partial fulfilment of the requirements for the
award of the degree of
BACHELOR OF TECHNOLOGY
in
ELECTRICAL AND ELECTRONICS ENGINEERING
SUBMITTED BY
SHARON SAM KODUNTHARA
(Reg. No: 13018834)
ST. JOSEPH'S COLLEGE OF ENGINEERING & TECHNOLOGY, PALAI.
NOVEMBER 2016

ST. JOSEPH’S COLLEGE OF ENGINEERING & TECHNOLOGY, PALAI
CERTIFICATE
This is to certify that the industrial training report on “SHARJAH ELECTRICITY AND
WATER AUTHORITY, SHARJAH, UAE” is the bonafide report of the training presented by Ms.
SHARON SAM KODUNTHARA (Reg. No: 13018834) to the Department of Electrical &Electronics
Engineering, St. Joseph’s College of Engineering & Technology, Palai, in partial fulfillment of the
requirements for the degree of Bachelor of Technology in Electrical & Electronics Engineering
from Mahatma Gandhi University, Kottayam, Kerala under our supervision and guidance.
Ms.Lallumol K Johny Prof. P V Varkey
Training Co-ordinator HoD, EEE

PREFACE
An excellent training report by Sharon Sam Kodunthara, much beyond the expected level
of a third year Electrical and Electronics student. By God’s grace, let her continue this
enthusiasm in all her life. The corrections I made are very minor for the perfection of this
report. Wish her a bright future.
-Professor PV Varkey

i
ACKNOWLEDGEMENT
First and the foremost, we thank God Almighty who gave us the inner strength,
resource and ability to complete the work successfully, without which all our efforts would
have been in vain. This internship/training consumed huge amount of work, research and
dedication. Still, implementation would not have been possible if I did not have support of
many individuals and organizations. Therefore I would like to extend my sincere gratitude
to all of them. First and foremost let me thank my Head of Department Professor P.V.
Varkey in granting me the permission to carry out this training and for giving me the
necessary and appropriate guidance.
I thank the Station Manager and Operations Superintendent of Layyah Power Station for
permitting me to carry out the training at SEWA’s Layyah Power Station. I’d also love to
thank Mr Padma Kumar, Head of the Electrical department of Layyah Power Station for
guiding, enhancing my knowledge about the plant. I express my gratitude to all the
operators, engineers and technicians at Layyah Power Station.
Also I express my heartfelt thanks to industrial training co-ordinator Ms.Lallumol K
Johny Asst, Professor, Dept. of Electrical and Electronics Engineering and other
supporting faculty from the department for their valuable inputs.
I thank my dear parents and all my friends for their support and co-operation.
Once again I extend my gratitude to all those, who had directly or indirectly influenced on
the work.

ii
ABSTRACT
Sharjah Electricity & Water Authority has witnessed consecutive huge development since
its inception as a private company called Sharjah Electricity & Water Resources Co., then
its ownership was transferred of to Sharjah Government as (Sharjah Electricity & Water
Department).
With the tremendous economical, industrial and civilization development boom witnessed
in the Emirate of Sharjah, His Highness Sheikh Dr. Sultan Bin Mohammed Al-Qasimi,
Member of Supreme Council and Ruler of Sharjah issued his visionary decree on
establishment of Sharjah Electricity and Water Authority (SEWA) as financially and
administratively independent entity, to generate and distribute electricity, water and gas to
the nationals and residents of the emirate.
Under the guidance of His Highness Sheikh Dr. Sultan bin Mohammad Al Qassimi, the
Ruler of Sharjah, ambitious expansions and development projects were implemented by
SEWA to cope pace with the comprehensive development process coupled with
tremendous constructional expansions witnessed in the Emirate of Sharjah.
Electrical Power: Several new generation units, transmission and distribution substations
were installed to raise the power generation, transmission and distribution capacities.
Water Supply: Similar growth trend was witnessed in field of water supplies with the
commissioning and development of more desalination plants and well fields. In 1995,
SEWA established "Zulal Water Factory" as an unprofitable government organization to
produce quality bottled fresh water with best international standards and specifications.
Piped natural Gas Service was introduced by SEWA for domestic, commercial and
industrial purposes as First of its kind in the region. Introduction of piped gas supply in the
Eastern Zone Gas is also in progress.

iii
CONTENTS
Sl.No. TITLE Pg.No.
PREFACE i
ACKNOWLEDGEMENT ii
ABSTRACT iii
CHAPTER 1 HIERARCHY OF POSITIONS HELD 1
CHAPTER 2 INTRODUCTION 2
CHAPTER 3 WORKING OF STEAM TURBINE 5
CHAPTER 4 STEAM UNIT(CONTD) &CONTROL ROOM 11
CHAPTER 5 PLANT VISIT AND LOW VOLTAGE 15
CHAPTER 6 UPS AND PROTECTION 23
CHAPTER 7 PROTECTION 29
CHAPTER 8 RO PLANT 35
CHAPTER 9 TRANSFORMERS AND FIRE FIGHTING 40
CHAPTER 10 MOTOR TESTING 44
CHAPTER 11 INSTRUMENTATION 47
CHAPTER 12 DESALINATION PLANT AND EARTH MAT 55
CHAPTER 13 GAS TURBINE 58
CHAPTER 14 GAS TURBINE (CONTD) 65
CHAPTER 15 MOTOR WS AND TRANSMISSION 69
CHAPTER 16 CONCLUSION 73
PERSONAL NOTE 74

Internship Report on SEWA, Sharjah, UAE
Dept. of Electrical & Electronics Engineering, SJCET, Palai Page 1
CHAPTER 1
HIERARCHY OF POSITIONS HELD
The Hierarchy of positions held by Persons and their qualifications.
Generation Manager
|
Station Manager
|
Deputy Station Manager
| |
Maintenance Superintendent Operations Superintendent
| |
Section Heads Senior Shift Charge Engineer
| |
Engineers Shift Engineer
| |
Asst. Engineers Asst. Engineers
| |
Supervisors Unit Operators
| |
Foreman Asst Unit Operators
|
Technician
Hierarchy
The positions held by supervisors, foreman and technicians are diploma or ITI, but all
other positions demand an Engineering degree. Now as the standards of education
have increased, employees with MS/Mtech are more preferred.

CHAPTER-2
INTRODUCTION
SEWA has a total generating capacity of 2500 MW which is generated through three
generating stations located at strategic locations in Sharjah namely, Layyah Power
and Desalination Station (900MW), Wasit Power station (1100MW) and
Hamariya Power station (440MW), of which Layyah Power station generates power
in the most economical manner. The training was at Layyah Power Station.
Heat recovery Boiler

Desalination Plant
Layyah Power and Desalination station was built in several stages, beginning in 1977.
It is still undergoing expansion. It is located in Sharjah near the Sharjah Sea Port
(Khalid Sea Port). Its 6 km away from the city and the area of the whole of the plant
extends up to 2 km. It is certified to ISO-9001:2000, is the major plant that provides
the most electricity and water requirements in Sharjah. It has Thermal units, Gas
turbines and Desalination plants (Multistage flash (MSF), Multi Effect
Desalination (MED)).
 Steam Power Generation:
Layyah has 8 Thermal units (steam turbine) with total generating capacity of 432
MW. The fuels used in steam turbine are CNG and heavy fuel oil.
 Gas turbine Power Generation:
Layyah has 9 Gas Turbines with total capacity of 464 MW and the fuels used in gas
turbines are Natural Gas, light fuel oil (LFO) or diesel.

 Waste Heat Recovery Boilers: Seven heat recovery boilers are connected to
gas turbines. They are used to reduce the flue gas emission temperature and
produce steam for desalination units.
 Desalination Units: Layyah has 10 distillers with a total capacity of 59
million gallons per day. Five of the distillers are multi stage flash evaporation
and four distillers are Multi Effect Desalination and one distiller Reverse
Osmosis.
 Nano Filtration Unit: It is installed with Desal 9 to improve production of
distillate water.
Generating Capacity-Diagram

CHAPTER-3
WORKING OF STEAM UNIT AND CONTROLS
Knowledge acquired:
 Familiarization of the plants and its generating capacity.
 Working of Steam Turbine and its important elements
 Control of turbines using the DCS system
In detail:
Thermal Units
There are eight steam turbines which are divided into three phases. Phase 1 consists of
4 steam units, Phase 2 consists of 2 steam units and Phase 3 consists of 2 steam units.
Phase 1:
 Units: 4 steam units.
 Generating capacity of each: 33.6 MW
 Generator voltage of each: 10.5 kV
Phase 2:
 Generating capacity of each: 75 MW
Phase 3:
 Generating capacity of each: 75MW

The total generation capacity of steam turbines is: 432MW
Gas Units:
There are 9 gas turbines named as A, B, C, D, E, F, G, H, and K.
A, B has 22 MW each.
C, D 33 MW each.
E, F, G 36 MW each.
K, H 123 MW each.
In Detail about Steam Turbines:
Since its winters in the UAE, and load requirement is less and hence Phase 1 of steam
units are shut down. Below the details of Phase 1 units are provided. (Details, SLD)
Working of steam turbine:
The details of the generator and turbine used in the phase 1 unit are: The make of
generator is ELIN with 33MW capacity each. Working of steam turbine is explained
showing the phase 1 unit which has four steam units in total.

Make and details of the Turbine of Phase 1

Make and details of the Generator of Phase 1
 Initially boiler drum should be maintained at normal working level that is the
water used is demineralised water whose pH is 9.4.
 Using the FDF (force draft fan) air is sucked from the atmosphere, this air
should be maintained in 450 mmwg. In consists of an Inlet damper that
controls the amount of air to be taken and a Discharge damper that controls

the air to be discharged. Then one of the burners is combusted to heat up the
Boiler, this is called cut-in of burner, here the mixture of air and fuel (Natural
Gas) of ratio 1:10 is combusted using the ignition system.
 When the boiler starts heating up and when steam pressure reaches 5 bar the
manual vents are closed and automatic start up vent is opened and pressure and
temperature must be maintained through the start-up vent (pressure is 35 bar
and temperature 350 degree Celsius). This is done by passing the steam
generated through the inbuilt system in the boiler that consists of cyclone
separator, primary super heater, de super heater and secondary super heater.
 Now it begins to charge the steam line through drains and traps, this is called
Cold start up, so before charging, the trap, drains are kept open and the water
in this cold condition will be released through the opened trap and drains.
 The turbine should not be in standstill state so before cold start up rolling
turbine should be on turning gear with 225 rpm.
 Turning gear system is operated through the hydraulic system and turbine
vacuum to be maintained -.95 bar pressure.
 The turbine has stop valve and control valve, when system is in service and
when unit suddenly trips stop valve will be closed. In the cold start-up it takes
about 45-60 minutes for the turbine rpm to reach 3000 rpm and this condition
is called synchronising stage.
 Once synchronised turbine’s inner flange temperature is to be maintained 70-
80 degree maximum and the turbine has 5 bearing which is to be maintained at
60 degree Celsius.
 The generator here is water cooled generator.
 Burners are combusted as per load demand, through governors.
 The maximum temperature and pressure of steam is 510 degree Celsius and 75
bar at full load.

 The steam is then passed through the steam line where it is then used to rotate
the turbine blades; this is coupled to the generator.

CHAPTER-4
STEAM UNIT (CONTINUED) AND CONTROL ROOM
The explanation of SLD is given below:
 The generator excitation is provided by exciter which is governed by AVR.
 The generator then produces 10.5 kV which is stepped up to 33 kV. Then by
using the Synchroscope, the voltage produced and the voltage on the bus bars
are synchronised and then supplied to the grid.
 The domestic voltage is 400 V for three Phase supply and 230 V for single
phase.
 Now to start the working of a generator, we will require supply from outside
for the working of various elements required for its start up for that we either
take supply from the currently working generator unit or from station
transformer. If not we can take supply from diesel generator too. (in case of
Phase 1 Unit)
 Once the generator starts working to produce 10.5 kV (in phase1 unit) and it’s
stepped up to 33kV through the generator transformer and it goes to the 33kV
bus bar.
 For unit transformer which is used for internal supplies it steps down to 3.3kV,
this 3.3 kV intermediate voltage is required in order to work the motors and
other machines at a normal rating.
 If it’s directly stepped down to 400V then rating will be very high and the
machinery would require better insulation and greater costs. Hence we require
this intermediate section. Using the auxiliary transformer we step down 3.3kV
to 400V for supplying station and unit auxiliaries working in low voltage side.
 The SLD is given below.

SLD OF PHASE 1

About AVR
 Automatic Voltage Regulator (AVR) Excitation systems are those fitted on
steam, gas or hydro turbines or diesel or gas engines.
About Synchroscope :
 For two electrical systems to be synchronized, both systems must operate at the
same frequency, and the phase angle between the systems must be zero (and
two poly phase systems must have the same phase sequence).
 Synchroscopes measure and display the frequency difference and phase angle
between two power systems.
 Only when these two quantities are zero is it safe to connect the two systems
together.
 Connecting two unsynchronized AC power systems together is likely to cause
high currents to flow, which will severely damage any equipment not protected
by circuit breakers.
Control Room:
 DCS is distributed control system (DCS) it’s a control system for a process or
plant, wherein control elements are distributed throughout the system for a
process or plant.
 The operators explained about the various commands, operations done in this
system through computers.
 There are different kinds of alarms in the control room. There are yellow
alarms, red alarms, sirens, audible alarms, trip alarms.
 Once an alarm is recognized the operator has to give an Alarm
Acknowledgement signal and do further checking.

Analog System
DCS system
 The control room also employs the analogue system of controls.
 The control panels of circuit breakers like Air Circuit breakers, SF6 breakers,
of which SF6(132 kV, 33kV) has the most arc quenching and dielectric
properties.
 Air Circuit breakers are used mainly for 3.6 and 6.6 kV; Oil Circuit breakers
are used for 33kVand SF6 for 132 kV.

CHAPTER-5
DAY 4-PLANT VISIT AND LOW VOLTAGE SECTION
Phase 2 and 3 of the steam unit (Phase 1 was shut down). Boilers, air drums, FD
fans, Burners, etc. The pictures are below:
Burner Tubes
Boiler Top of Unit 5 and 6

Water Storage tank
Plant Images

Chimney
FDF motor Motor of coolant

Generator -Unit 6 Auxiliary transformer
Auxiliary transformer details of unit 7

LOW VOLTAGE SECTION:
There are 2 sections in boiler boards and three sections in turbine boards.
380 V Turbine Board 380V Boiler Board
The whole unit
 As in the boiler board SLD below: the two transformers are of 160 kVA rating
on each section. They step down to 400 kV.

SLD
 In the boiler board there are two sections, in each section there are two groups
of current transformers (one at the neutral and other set on the lines ie. 4
numbers in total) where the current transformers together act as REF
(restricted earth fault) and the other single CT in the neutral acts as Standby
earth.
 The standby earth gives protection to the whole system whereas the REF
protects only the restricted region. Then the breaker with overload and
magnetic protection (short circuit) closes, and the supply goes to withdrawable
cubicle units called the Motor Control Centre (MCC) through the bus bars.
 If any one of the transformers fails then the bus section is closed manually and
continues its working, and hence the transformer is designed such that it can
carry such full loads.

About MCC
Each MCC unit with cubicle door open
Coil inside the contactor A contactor
 In this section each MCC unit has one contactor for Direct on Line and two
contactors for forward reverse function.
 Starting methods of motor are Direct on line method, Star Delta Method,
Autotransformer method etc. The simplest method is Direct on Line method
as it is simple and voltage here applied is full voltage (400V).
 Once the start button is pressed the stepped down auxiliary voltage of 110V is
given to the contactor, once the contactor coil is magnetised, it completes the

circuit and motor is turned on and this contactor is in series with the overload
relay. But the current would be very high, so the MCC will be designed such
that it can withstand this high current (5 to 7 times).
 In order to control the motor in two directions we modify the MCC using the
Forward and Reverse contactors and its control.

CHAPTER-6
UPS AND PROTECTION
UPS (Power Electronics-EMD):
Automatic Voltage Regulator (AVR)
AVR
 The AVR as mentioned previously is the control system of the exciter of a
generator. The UPS system consisted of rectifiers, inverters and other
components.
 The UPS system is required for continuous power supply to the generator and
turbine components.

UPS System
 The inverter was explained to me, it consisted of thyristors, capacitors, cards,
cooling fans, and capacitors to adjust the power factor of the produced sine
wave.
CARD

Inverter
Working of a UPS system

 It consists of four units and a stand by unit. If any one unit fails, the stand by
unit comes into action. Now in the figure below one of the unit is clearly
explained.
 Once the breaker is close the AC supply from the mains is given to the ac to dc
converter(rectifier). This dc supply from rectifier helps to recharge the battery
bank connected across it, this dc supply is again converted to ac in the inverter
and through a static switch is then synchronised from the ac coming from the
transformer, once its synchronised and given to the feeders.
 If the breaker from the main ac supply for inverter rectifier is not closed then
the battery bank provides the necessary DC supply for the inverter. The battery
bank image is below:
Battery Bank

Protection Department:
After seeing the UPS system an engineer from the protection department guided me to
his department. He explained to me that there are three kinds of protection relays
namely Electromechanical, Static and Digital relays, of which digital are the most
compact and electromechanical is the oldest kind. Suppose anything from the normal
occurs the relay will sense and trip the unit, also will send an alarm that the unit has
tripped and requires urgent maintenance.
Different Kind of relays employed in Phase 1 unit.

Testing of a digital relay
Under voltage relay was being tested, if the voltage level goes below 50% of 110 V
the relay would trip the unit. However after the test was conducted it was seen that the
relay successfully gave the alarm, and hence was approved to be used in the required
area.

CHAPTER-7
PROTECTION (MAINTENANCE WING)
EMD Protection. There are other maintenance departments like Mechanical (MMD),
Instrumentation (IMD), and Chemical (CMD).
Relay Testing Unit
The tests of the following relays were being carried out:
 Transformer Protection relay kept in the primary side(6.6 KV)
 Standby Earth Fault relay kept in the secondary side (380 KV)

 Restricted Earth fault relay kept in the secondary side (380 KV)
The relays were being tested in SVERKER 780-Relay Test Unit (Meggar). Initially
the details of the relay, its brand, code number, previous tested values, Test Unit are
all noted in the computer system.
Earth Fault Relay-Static type
 During the testing, the time range is first set. When current value exceeds the
normal capacity of the relay, it holds the value for the time range that’s set and
then the unit trips, Then there is instantaneous time, for which the unit trips
within milliseconds once overload or fault is recognized.
 Once the unit trips, the time, its current, instantaneous time are all noted in the
computer system and compared with the previous tested values, if there’s not
much difference its is approved as tested and is placed back in service.
 After testing these relays and being approved as Tested, these has to be put
back into service. In the Phase 4 low voltage side room. Here the Standby
Earth fault relay and Restricted Earth Fault relay were placed back on the 380
V Lighting and HVAC board. In the 6.6 KV room the spare SF6 breakers kept

outside. In 6,6 KV room all the breakers used are SF6 Breakers, and all the
relays are either Digital or Static.
380 V room of Phase 4
 Inorder to place back the Transformer Protection relay we came to the 6.6 KV
room. The images are below.
 Once the relay is placed back in the unit, the control breaker is switched on.
6.6 KV Room

Before keeping the relay The relay being placed
Sf6 circuit breakers

 The two transformers of 33KV/6.6KV and auxiliary transformer of
6.6KV/380V. In the control room of Phase 4 and the cable gallery. The cable
gallery cables are those that go to the control room and other parts.
33KV/6.6KV Transformer-Phase 4
Cable Gallery

About Phase 4
Phase 4 consists of:
Desalination units -9, 10, 11, 12.
Pump House
Nano filters
7 HRSG (Heat Recovery Steam Generator)

CHAPTER-8
RO PLANT
 The usable drinking water produced by the RO plant is 5 million gallons per
day. It has two 33KV/6.6KV (15MVA) transformers and two auxiliary
transformers of 6.6KV/400KV (3000 KVA).
 If any one of the main or auxiliary transformer fails then the bus section is
closed and working is continued unhindered. Therefore the transformers are
designed such that it can accommodate full load.
 There are five pumps of which the two High pressure pumps are of 6.6KV
Variable frequency Drive type. It is variable frequency because N=120f/P. As
the frequency changes speed can be controlled.
Main transformers and Auxiliary transformers

 The red pipes seen in the image above is the Fire Fighting System employed in
transformer called the Deluge system.
In the 6.6KV room and then to the 380 V switch gear room where the VFD, Bus
Section, and Incomer etc are seen on the corresponding boards. The pictures are given
below:
380 V Switch Gear
6.6KV room-HV section

RO TRAIN
Plant Overview

 As in the figure, initially sea water is taken from the sea through pumps. Sea is
almost 500 m away from the plant and pumps laid are 40-50m deep in the sea
and it pumps the sea water to the plant.
 The sea water is then allowed to go through a band screen (works like a
strainer) which takes off all the contaminants. Then the debris is cleaned from
it.
 After which the electro chlorination process takes place, here the sea water is
passed through cells which consists of titanium. The plated part is positive and
the other is negative from here hypochlorate solution is formed from which
chlorine is obtained. This chlorine is dosed on to the sea water which helps to
remove unwanted contaminants like sea growth, jellyfish etc.
 Then it goes to the DAF where chemicals like Ferric Chloride and Sulphuric
acid are added in order to remove the oil content and other matters.
 From DAF it goes to clarified water tanks.
 Then Sodium Bisulfate and Antiscalant are added in order to remove chlorine
then passed to the RO Trains A and B, each of capacity 2.5 million gallon,
 Finally Lime and Sodium Hypochlorate are added so as to make it drinking
water and is stored in the storing tank.
Storing tank

Terminal Inspection of a transformer. It is done yearly in order to check if
any oil leakage or loose connections are there.
Terminal Inspection of Transformer

CHAPTER-9
ABOUT TRANSFORMERS AND FIRE FIGHTING SYSTEMS.
Transformer
Transformer has a core and windings are mounted over it, first LV winding then
insulation is given, over it HV winding is placed. This is placed in a tank which
consists of oil in case of oil filled transformers. Oil serves two purposes: as cooling
medium and as insulation. All the three phase transformers used here are core type
which consists of three limbs.
Electrical tests:
 Commission testing: This testing is done when a brand new transformer is
installed in a plant. This is done in order to see if it has the required
specifications, if any changes or damages occurred during shifting or
installation. All the transformers in this plant are commissioned. There are
about 32 tests and it can vary from company to company and as per
requirement.
 Diagnostic Testing: This testing is done during the service of the transformer
at specific durations to prevent faults. It’s also called Preventive Maintenance
Test. It consists of 18 tests.
 Acceptance Testing: After a repair on transformer is done in order to know if
the repair is successful, we do acceptance test. It’s about 4 tests.
If any physical abnormality like high water content, low break down voltage occurs,
it can be rectified using transformer filtration. If any chemical abnormality like
acidity occurs, it can be rectified using oil regeneration. Depending on the rating and
previous values these tests are conducted on transformers at successive intervals.
Generator, transformer, motor and switch gears have common tests (Commission
testing, Diagnostic Testing, Acceptance Testing).Vector Group: The arrangement of
windings in the primary and secondary of transformer is called the Vector Group.

 The three phase transformer windings can be connected several ways. Based
on the windings’ connection, the vector group of the transformer is determined
 The transformer vector group is indicated on the Name Plate of transformer by
the manufacturer. The vector group indicates the phase difference between the
primary and secondary sides, introduced due to that particular configuration of
transformer windings connection.
 The determination of vector group of transformers is very important before
connecting two or more transformers in parallel.
 If two transformers of different vector groups are connected in parallel then
phase difference exist between the secondary of the transformers and large
circulating current flows between the two transformers which is very
detrimental. (Yyo; Dy ||; Dy1 etc)
Fire fighting system:
 The fire fighting system employed in this plant is by the US Company
Secutron.Inc.
 It has 8 loops that go to various parts of the power station.
 Initially a 230 V supply is given and its stepped down to 24 V DC which goes
to all the loops.
 If anything is detected, a bell system is arranged in order to alarm those in the
control room.
 It has no automatic actuator that will put out the fire, instead must be put out
manually.
There are two kinds of detectors: Conventional and Addressable.
Addressable detectors shows the exact address of the place where there is an issue
whereas conventional gives which area is under problem and each component has to

be tested. In fact there exist many different kinds of modules that convert the existing
conventional systems into addressable system.
Secutron.Inc Fire Alarm system
Deluge fire fighting system:
 Deluge systems are connected to a water supply through a deluge valve that is
opened by the operation of a smoke or heat detection system. The detection
system is installed in the same area as the sprinklers.
 When the detection system is activated water discharges through all of the
sprinkler heads in the system. Deluge systems are used in places that are
considered high hazard areas such as power plants, aircraft hangars and
chemical storage or processing facilities.
 Deluge systems are needed where high speed suppression is necessary to
prevent fire spread.

 Deluge Fire Sprinkler Systems differ from conventional Fire Sprinkler Systems
in the sense that all nozzles employed in the system are open and when water is
released into the system it flows from all discharge devices.
 As such, this special type of system is generally found within industrial type
hazards that require the application of water over a large hazard or area.
 The control of water is accomplished by the use of a Deluge Valve which is a
device that prevents water from entering the system piping until required.
 A detection system which may incorporate the use of heat, smoke, or flame
detectors is used to open the Deluge Valve when a fire or its products of
combustion are detected.
 All system piping is filled with water which discharges from the open
sprinklers and nozzles used in the system.
Maintenance manuals in the EMD

CHAPTER-10
MOTOR TESTING
Motor Testing

About Motor Testing:
The auxiliary boiler 32 used to produce steam of Phase 4 had a combustion fan whose
motor got damaged due to high starting current. The current through each phase that is
R, Y and B should be same, if any miss match occurs then the fan damages. Here the
same problem occurred. The motor now used here was double the rating of the
previous motor used and hence the belt ratio had to be adjusted. It was an experimental
approach. The fan in this boiler has a discharge damper. Initially its 20% opened and
then its 100% opened in order to purge out the unburnt gases after purging again
keeping 20% open ignition is done.
ABOUT INCOMER.
 An incomer in order to be earthed it must be first racked out; not only that but
also from where the supply is coming to the incomer, there also it must be
racked out else the wire will be live and if it is earthed, short circuit happens.
 Only if it’s racked out from the supply too it can be earthed. In case of Bus
section also called bus coupler has two live wires.
 There is an interlock system called Castle Interlock system which is
provided for safety within the system. Only if it is locked it allows to be
earthed.
Castle Interlock

Incomer
Switch gear of desal 13

CHAPTER-11
INSTRUMENTATION
Instrumentation department.
 In order to control various process parameters like Flow, Pressure,
Temperature, Oxygen etc. we use control systems.
 Control System helps to measure, monitor and control these parameters.
 For e.g. in order to measure and control flow.
 Initially the differential pressure of water flowing is measured and is passed
through a differential pressure transmitter.
 The signal coming from the transmitter can range from 4-20mA.
 This current coming can be used for recording, indication, Alarm, Protection,
control.
 In case of Alarm, the signal is passed through a Limit Value Monitor.
 If the current reaches 75% then the alarm gives a yellow signal.
 The operator in this case in the control room must make the necessary changes
either manually or automatically.
 If it reaches 80% then there will be red signal, if there is no necessary action
taken then logic gate is designed such that it will trip the unit if two or more
alarms are activated.
 Suppose if necessary action is taken by the operator then the signal goes to a
pneumatic converter where the current is converted in the range of 3-15 psi.
 Then it will go through a positioner where a boost signal is given, then
accordingly the valve will be positioned and flow will be controlled.

 The operator controls each unit distributed along the C-net through the
Programmable Control Unit (PCU).
 A control logic diagram also called as CLD was then explained.
 The figure is given below
 The signal 4-20mA is given to the Low Set Point Block. If it’s below 15 then
there is a time delay of 120 seconds.
 If for 120 seconds the value is below 15 then a RED alarm is given.
 Similarly there are various set points, if any of the value goes above or below
the permissive limit for a time range of 120 seconds then an alarm is given.
 This is same in case of pressure, flow and all other process units.
Why we use 4-20 mA as standard signal?
When we use 0-20mA and if there is a power failure we will not know. But in case of
4-20mA, when there is a power failure the value indicated will be 0 mA and hence we
understand there is failure in the supply. When it is at 4mA it is called Live Zero.
There are different kinds of measuring instruments.
 Dial type.
 Thermocouple
 RTD- Resistance Temperature Device
There are two kinds of errors:
 Span Error
 Zero Error
Some instruments may have compound error; these errors can be removed by using
calibration.

Type of Instruments:
 Dial type instruments will have a dial inside that moves as per the changes in
the parameters sensed by it.
 A thermocouple is an electrical device consisting of two different conductors
forming electrical junctions at differing temperatures.
 A thermocouple produces a temperature-dependent voltage as a result of the
thermoelectric effect, and this voltage can be interpreted to measure
temperature.
 Thermocouples are a widely used type of temperature sensor. There are
different type J,K, R type etc.
 RTD stands for Resistance Temperature Detector
 RTDs work on a basic correlation between metals and temperature. As the
temperature of a metal increases, the metal's resistance to the flow of electricity
increases. Similarly, as the temperature of the RTD resistance element
increases, the electrical resistance, measured in ohms (Ω), increases. RTD
elements are commonly specified according to their resistance in ohms at zero
degrees Celsius (0° C). The most common RTD specification is 100 Ω, which
means that at 0° C the RTD element should demonstrate 100 Ω of resistance.
 Platinum is the most commonly used metal for RTD elements due to a number
of factors, including its :(1) Chemical inertness
(2) Nearly linear temperature versus resistance relationship,
(3) Temperature coefficient of resistance that is large enough to give readily
measurable resistance changes with temperature and
(4) Stability (in that its temperature resistance does not drastically change with
time).

 Other metals that are less frequently used as the resistor elements in an RTD
include nickel, copper and Balco.
Dial Type
Standard Digital Thermometer
Comparator used for calibration

Dial Type-Pressure Measurement Gauge with Glycerine
(Glycerine-used for accurate measurement due to vibration)
Pneumatic Positioner

Solenoid Valve Pressure Transmitter
A pressure transmitter in olden days was a four wire system, but this was considered
not to be a good method as it involved more cost and more loss. Hence now the 2 wire
system is widely used. To demonstrate this, an experiment was set up by the Engineers
for me.
Experimental Set up

Here the pressure transmitter had 0-30 bar pressure rating, so for each value of
pressure applied the current was shown in the multimeter. Here they used the two wire
system. For pressure applied corresponding value were shown, when 100% pressure
was applied, the maximum value was 20mA. The instrument used could calibrate up
to 0-1 bar pressure.
Two Wire System:
 A two-wire transmitter draws current from a remote dc power supply in
proportion to its sensor input. The actual signal is transmitted as a change in
the power supply current.
 Specifically, a thermocouple input transmitter will draw 4 mA of current from
a dc power supply when measuring the lowest temperature of the process.
 Then, as the temperature rises, the two-wire transmitter will draw
proportionally more current, until it reaches 20 mA. This 20 mA signal
corresponds to the thermocouple’s highest sensed temperature.
 The transmitter’s internal signal-conditioning circuitry (powered by a portion
of the 4-20 mA current) determines the temperature range that the output
current signal will represent.
 Physically, only two copper wires are necessary to connect the transmitter
output signal in a series circuit with the remote power supply and the process
equipment. This is made possible since the signal and the power supply line are
combined (one circuit serves a dual function).
UNDERSTANDING DCS
 Each operator workstation consists of two computers.
 There are eight workstations.
 As the operator adjusts the set point value in the system, corresponding
changes occurs in the required unit.
 It communicates via the C-net to the corresponding PCU and then to the desal
unit.

DCS screen
PCU Controller
Above is the PCU from where the instructions and commands are given to the field
and received from the field. The latest system of controller is shown above too.

CHAPTER-12
DESALINATION PLANTS and EARTH MAT
The hot gas produced in the Gas turbine plants go to the heat recovery steam
generators and then to the desal plant to produce steam. Desalination plants are of two
types Multi Stage Flashing and Multi effect distillation.
MULTI STAGE FLASHING
Overview
In multi stage flashing - high temperature and low pressure. Eg are Desal 5,6,7,8,9

Seventeen stages in MFD
Here almost 2500 tonnes sea water is taken and 1200 tonnes of drinkable water is
produced. It passes through seventeen stages. Stages 15-17 are rejection stages. Stages
1-14 we get the drinkable water.
MULTIEFFECT DISTILLATION:
Five cells in MED
Multi Effect Distillation Plant. In Multi Effect Distillation Plant-Low temperature
and high pressure. Eg: Desal-10, 11, 12, and 13. In this there are five cells out of

which water is passed through and out of 5000 tonnes of sea water taken and 1500
tonnes of drinkable water is produced.
Earth Mat
In an electrical substation a ground (earth) mat is a mesh of conductive material
installed at places where a person would stand to operate a switch or other apparatus;
it is bonded to the local supporting metal structure and to the handle of the switchgear,
so that the operator will not be exposed to a high differential voltage due to a fault in
the substation.
Lightning Arrester
A lightning arrester is a device used on electrical power systems and
telecommunications systems to protect the insulation and conductors of the system
from the damaging effects of lightning. The typical lightning arrester has a high-
voltage terminal and a ground terminal. When a lightning surge (or switching surge,
which is very similar) travels along the power line to the arrester, the current from the
surge is diverted through the arrestor, in most cases to earth.

CHAPTER-13
GAS TURBINE
Gas Turbine-K
There are nine gas units in this power plant.
Gas Turbine A
Gas Turbine B
Gas Turbine C
Gas Turbine D
Gas Turbine E
Gas Turbine F
Gas Turbine G

Gas Turbine H
Gas Turbine K
 Gas Turbines A-G produce 11KV voltage and H,K produce 15 KV.
 GT-A and B use aircraft engines. The advantage of using aircraft engine is
that it makes the unit start in less than three minutes with a speed of 3000 rpm.
 Except A and B all other GT units (its generator, transformer, exciter) are of
GEC Alstom make. A and B make is Brush.
 The gas turbine uses LFO or CNG as fuels.
 Each gas unit has an air filter that cleans and filters the air.
 A few GT units are started using 6.6 kV starting motor.
 Air is taken from the atmosphere and through the guide vanes it goes to the
engine, and when certain speed reaches ignition takes place.
 The exhaust gases from the engine go to the turbine blades and are coupled to
the generator and when its 3000 rpm, excitation is given and generator
produces 15 kV.
 The hot flue gases produced from the firing is used to rotate the turbine.
 In normal cases the hot gases are then released to the atmosphere via chimney.
But here it is fed into the boiler where it is used to produce steam. This
produced steam is carried to the Desalination plant.
 The generated voltage is 15 KV (in case of unit K and H). This is then stepped
up to 132 KV and fed to the 132 KV substation via the bus bars to the feeders.
 In case of black start the unit is started using diesel generator or outside supply.
 The transformers uses ONAN cooling method and employ on load tap
changers.
 The bus bars connected go to the substation rooms.
 The name of the panel in transformer is called Marshalling panel.

 The unit requires uninterrupted power supply too for continuous working.
 Suppose when the generator is out of service then the space heater is turned on
in order to prevent any moist in the generator.
Generator End of GT-H Turbine End of GT-H
Bus Bars of GT-H (Bus bar trunking)

15/132 KV trfr
In the transformer above, we can see an oil reserve; this oil is used for cooling the
transformer, if it goes below the required level an alarm is given,
Marshalling Panel of a transformer

Transformer name plate
Cooling fans

The green tubes carry water for cooling the gas turbine unit
Pipelines that carry hot gases to HRSG produced from GT units

 The yellow tubes carry natural gas.
 The blue tubes carry air.
 The green tubes carry cooling water.
 The red structures in the plant are mainly fire fighting systems.

CHAPTER-14
GAS TURBINE
Overhead cables and pipelines carrying fuel, air, cooling water of Gas Turbines
The generator is of GEC ALSTOM make; a France company.
Specifications are:
GENERATOR
Apparent Power: 35575 kVA
Voltage: 11000 V
Current: 1875 A
ECXITER

Apparent Power: 91 kW
Voltage: 211 V
Current: 431 A
Exciter
Generators require direct current to energize its magnetic field. This is obtained from
exciter.

The field visit was with the ALSTOM specialist when they were working on the
generator. The images are below
Stator Windings of a generator
Boiler

Chimney

CHAPTER-15
MOTOR WS AND TRANSMISSION
Maintenance
In the EMD department there is:
 Breakdown maintenance
 Routine or Preventive Maintenance
 Trouble shooting
There are 17 units and timely maintenance is done throughout the year. Over hauling-
Preventive/ Predictive Maintenance tests are done based on equipment. We keep
history of all maintenance and troubleshooting works done in the plant so that if
similar problem occurs in the future we can keep in track of the measures used
previously in this.
Motor Workshop
Here motors were repaired and tested. The AC motors, its stator, core and the
equipment used to separate them in order to carry out repair work. Once the repair is
done the motors are tested and their current, voltage values etc. are noted.
Motor

Stator and Rotor
STATOR ROTOR
Boiler Testing-Few major testing in Boilers are:
 Hydraulic Testing: In this testing the steam valve to the turbine valves are
closed and boiler’s hydraulic pressure is increased upto 110 bar. This test is
done in order to check if there are any inside or outside leakages, Other testing
are safety valve testing, commision testing etc.

Fire Extinguishers:
The fire extinguishers are either compressed CO2 or compressed water stored under
very high pressure and is released when there occurs a fire fighting situation.
Compressed CO2
SF6 Circuit Breakers
The working of SF6 CB of first generation was quite simple it is to some extent similar
to air blast circuit breaker. Here SF6 gas was compressed and stored in a high pressure
reservoir. During operation of SF6 circuit breaker this highly compressed gas is
released through the arc in breaker and collected to relatively low pressure reservoir
and then it pumped back to the high pressure reservoir for re utilize.

In the manual working of SF6 CB during closing and tripping. When the circuit trips
the sound is higher that when it is closed. The chance of arcing to occur is because
when circuit breakers are tripped, they trip when a very high current is there. But SF6
has high arc quenching properties.
SF6 CB
132 KV Substation (Transmission)
Here 132 kV goes to the feeders.From there voltage is stepped down to 66kV, 11kV
and passed to different substations and feeders. For domestic purposes its stepped
down to 380V.

CHAPTER-16
CONCLUSION
SEWA is one among the largest, most vibrant, and productive Public Sector
undertaking, and is fully owned by the Government of Sharjah.
Electrical Power: Several new generation units, transmission and distribution
substations were installed to raise the power generation, transmission and distribution
capacities.
Water Supply: Similar growth trend was witnessed in field of water supplies with the
commissioning and development of more desalination plants and well fields. In 1995,
SEWA established "Zulal Water Factory" as an unprofitable government organization
to produce quality bottled fresh water with best international standards and
specifications.
Piped natural Gas Service was introduced by SEWA for domestic, commercial and
industrial purposes as First of its kind in the region. Introduction of piped gas supply
in the Eastern Zone Gas is also in progress.

Personal Note…..
“You will become a good Engineer” these were the last words I heard before leaving
the power station after completing my training. Hearing this from my trainer really did
not satisfy me but rather it laid a huge responsibility on me. I am indeed happy to have
made the choice of taking training in Layyah Power Station. It was one of the biggest
exposures I got to the world of power generation.
I want to thank the authorities for granting me this opportunity and all the department
heads for spending their valuable time on me in helping me learn more about the plant.
Let me thank Mr. Padma Kumar, Mr. Ahmed Kamal, Mr. Ahmed Samsi.
Also Mr Rajangam, Mr. Niyas, Mr. Abdul Kareem, Mr. Ravindran, Mr. Rameshan
and Mr. Noushad.
I’d like to my Dad too for helping me come to this power house.
A huge vote of thanks to everyone who were directly and indirectly involved in this.

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