3. Submitted To
CE PMU+P&I DEPARTMENT
Submitted By
Internee Name: Ahmad Masood
Registration #: Fa12-Bs(EE)-077
Department: ElectricalEngineering
Session:2012-2016
From: GEPCO
COMSATS Institute of Information
Technology, Sahiwal
4. Abstract:
The report is aboutmy internship tenure of 6 Weeks which made me learn the
basics of a power distribution. There are manydepartmentspresent in GEPCO
headquarter. Following departmentsin which I did work and get experience. A
very passionatemanagementanda highly skilled and disciplined man power
and most importantlytheir mutualcoordination makes GEPCO known all.
5. Acknowledgement:
First and foremost, thanks to “AlmightyALLAH” whogave me the strength and
will to go out in search of knowledgeand who is alwaysour greatest well-wisher.
I am thankfulto great Sir WajahitGill which belongs from Human Resources
department, especially ThanksXen. Muhammad Botta and sir Tahirbutt from
PMU (project managementunit) department
, Also special thanksof Sir Mian Irfan Deputy director of CS (customer services)
departmentand also greatly thanksXen. Imran butt and Mr. ZubairButt From
P&I (protection and instruments) departmentwho hasassisted me throughout
my internship tenure. Besides his skills and knowledgethey are thoroughlya
well-disciplined personality. I would alwaysremember their ditch efforts to make
me entangled in discussions thatultimately proved to be very fruitful .It was a
real feast being with him.
I am very obliged to all the personalities who were alwaysthere whenever I
asked for help. It was really a very good experience to be at GEPCO.
7. Chapter 01
Introduction
WAPDA:
Water and power development authority. The Water and Power
DevelopmentAuthority (WAPDA) is a government-owned public
utility maintaining powerand waterinPakistan, although it does not
managethermalpower. WAPDA includes Tarbela and Mangla damsamong
its resources. Its headquartersare in Lahore.
History:
WAPDA was established in February1959 to unify the maintenance
of infrastructure previously overseen by provincial agencies. Its Chairmen
included outstanding civil servants like Ghulam Ishaq Khan,GhulamFaruque
Khan and Aftab Ghulam NabiKazi who were subsequently President of Pakistan,
Minister for Commerce and Economic Adviser, respectively. In October 2007,
thermal power managementwassplit into the newly formed Pakistan Electric
Power Company(PEPCO).
WAPDA Water vision 2025:
WAPDA has formulated a
comprehensive $25–33 billion NationalWater Resource and Hydropower
Development Programme, entitled Water Vision 2025. TheWater Vision 2025
projects are expected to generate 16,000MW of hydroelectricity. Other goals are
to prevent water shortages, limit droughtand increase water storage for a
growing population. Five massive hydropower projects have been announced by
the President of Pakistan;these are to be completed by 2016, with a generation
capacity of 9,500 MW. Twoof the projects are ready for construction, while three
are in the stages of feasibility studies and preparation of tender documents.
8. Water Vision 2025 consists of three phases. PhaseI was expected to start in 1993
but wasdelayed. Thepriority of water sector projects underPhaseI of Water
Vision 2025 are GomalDam (NWFP), MiraniDam and Mithan Kot
Barrageat KachhiCanal(Balochistan)raising of Mangla Dam (Azad Kashmir),
Greater ThalCanalphaseI (Punjab) andThar/RaineeCanalsphaseI (Sindh).
The total cost of these PhaseI projects will be $2.467billion with a construction
period of five years. UnderPhase II, HingolDam,BalochistanDam and Satpara
Dam (Northern Areas), Chashma RightBankCanaland KhurramTangi
Dam (NWFP), phaseII of the Greater ThalCanal Akhori Dam and Sanjwal
Dam (Punjab), phaseII of Thar/RaineeCanals, Gajnaiand SehwanBarrage
(Sindh) willbe completed in 3–6 years, except Basha Dam, which will take 8–10
years for its completion. The total cost of PhaseII projects will be $8.94 billion.
These 11 projects will have a storage capacity of 12,790,000acrefeet (15.78
km3
), would generate over 3362 mW of power, and would irrigate 14000 square
kilometres of land. UnderPhaseIII, Yugo Dam, Skardu Dam, DhokDam, Rohtas
Dam,NaulangDam and KhadjiDam will be completed.
Gujranwala Electric Power Company:
Gujranwala
Electric PowerCompany (GEPCO)is an electric distribution companywhich
supplies electricity to Gujranwala,Punjab, Pakistan.
9. Chapter 02
Safety
The basic need of the safety is to prevent humanbeing from any type of injury.
2.1 General Safety:
Security is first stage of safety.
When we working in the plantarea we should use PPE’s(Personal
Protection Equipment’s)
They are mention as below:
Helmet:
It prevent us from the head injury.
Overall:
It’s a special type of dress and this dress is fit to body. Loose dress may be cause
of any accident.
10.
11. Safety Shoes:
They are prevent us from slipping and if something fell down they can bear25kg
weightby its toe and prevent us by feet injury.
Goggle:
It is used to save our eyes from dust.
Ear Plugs:
An earplug is a device thatis meantto be inserted in the ear canal to protect the
user's ears from loud noises produced by the heavy machines, dust or excessive
wind.
12. Gloves:
Gloves protect and comfort handsagainstcold or heat, damagebyfriction,
abrasion or chemicals, and disease; or in turn to provide a guard for whata
bare hand should not touch. They prevent us from hand injury.
13. Chapter 03
Transformer Protection
The high importanceand cost of transformers make it crucial to maintain these
assets. SEL hasdeveloped a wide variety of advanced transformer protection
relays for all your transformer applications, providing top-of-the-line protection
and control. Choose the relay and other equipmentthatbest suits your
transformer needs.
3.1 Current transformer:
measurement of alternating electric
voltage (or potential) transformers
instrument transformers.
A current transformer (CT) is used for
current.Current transformers, together with
(VT or PT), are known as
3.2 Potential transformers :
Potential transformers (PT) (also
called voltagetransformers (VT)) are a parallel connected type ofinstrument
transformer. They are designed to present negligibleload to the supplybeing
measured and have an accurate voltageratio and phaserelationship to
enableaccurate secondary connected metering.
3.3 Buchholz relay:
In the field of electric power distribution and
transmission, a Buchholz relay is a safety device mounted on some oil-filled
powertransformers and reactors, equipped with an external overhead oil
reservoir called a "conservator". TheBuchholz relay is used as a protective
device sensitive to the effects of dielectric failure inside the equipment.
3.4 Circuit Breaker:
A circuit breaker is an automaticallyoperated electrical
switch designed to protect an electricalcircuit from damagecaused by overload or
shortcircuit. Its basic function is to detect a fault condition and interrupt current
flow.
3.5 Surg arrester:
14. A surge arrester is a device to protect electrical equipmentfrom over-
voltage transients caused by external (lightning) or internal(switching)
events.
15. Chapter 04
Transformers
A transformer is a static machine used for transforming power from one circuit to
another without changing frequency. This is very basic definition of transformer.
132Kv to 11kv
4.1 Working Principle of transformer:
16. The working principle of transformer is very simple. It dependsupon Faraday’s
laws of Electromagnetic Induction. Actually mutualinduction between two or more
winding is responsible for transformation action in an electrical transformer.
4.2 Faraday’s laws of Electromagnetic Induction:
According to these Faraday’slaws,
"Rate of changeof flux linkage with respect to time is directly proportional to
the induced EMF in a conductor or coil".
e= M dI / dt
where
e = Induced voltage
M = mutualinductance
dI = rete of changein the current
dt = rate of changein time
If the circuit of the second coil is closed, current flows in it and so in this way
electric energy is transferred from one coil to the coil. The first coil in which
electric supplyis connected is called the primary coil and other coil to which
the power is supplied is called the secondary coil. In a brief transformer is a
device that
4.3 Transfers electric power form one circuit to the other:
It does so without changein frwquency.
It accomplishes it by the electromagnetic induction.
Where two circuits are electrically isolated butmagneticallycoupled.
4.4 Voltage Ratio of Transformer:
This above said ratio is also known as voltage ratio of transformer if it is
expressed as ratio of the primary and secondary voltages of transformer.
4.5 Turns Ratio of Transformer:
As the voltages in primary and secondary of transformer is directly proportional to
number of turns in the respective winding, the transformation ratio of transformer is
sometime expressed in ratio of turns and referred as turns ratio of transformer.
4.6 Types of the transformer GEPCO:
17. In all types of transformer, the core is constructed of transformer sheets,
steel laminationsto provide a continuousmagneticpath with minimum air
gap. Transformers are classified by several means,
According to Construction
According to Function
According to Consumer
According to Connections
4.6.1 According to Construction:
Construction ally, transformers are of two general types.
Shell type.
Core type.
4.6.2 According to functions:
Power tranformers
4.6.2.1 Power transformer:
Two windingstransformer
Three windingstransformer
Auto transformer
4.6.2.2Special transformer
(Current Transformer)
20. 4.6.3 According to consumer:
Transformers are also classified by means thathow a consumers uses it.
Step up transformer
Here turns of secondary are large then that of primary. i.e. outputvoltage is
greater than inputvoltage but on the other hand, primarycurrent is large than
that of secondary.
Step down transformer
Here reverse process takes place than thatof the step up transformer. Generally
above type of transformers are used in our power house.
21. Chapter 05
Switch Yard
5.1 Inside the switch yard:
Mainly there are different but most importantthingsfor the protection,
measurement, metering and for the other purposes.
Circuit Breakers
Isolators
Insulator
Insulator Strings
Bus Bar
Current Transformer (CT)
Potential Transformer (PT)
Conductor
Control Switch
Relays
There are different type of schemes are used but in our block III one and half
scheme is used.
5.1.1 ONE AND HALF SCHEME:
The benefit of this scheme is that if for example any fault occurs on any bus
bar then the supplyof the feeder will not disconnect. Then the supply will go to
the second bus bar without an interruption.
5.1.2 CIRCUIT BREAKER:
As we know circuit breaker is an on load device it meansthat it can do proper
work and do ON and OFF with safety due to supply. In these circuit breaker
we used SF6 for arc quenching medium andthese circuit breaker are air
operated. And the air pressure becomes 18 bar.
22. 132Kv to 11kv Transformer Circuit breaker
5.1.3 ISOLATERS:
While isolators are off load device means that it just like work as a fuse it do
work only at off supply. Becauseit did not keep any arc quenchingmedium if we
use at an on load supply then it will become damage,Soevery bay consists of six
isolators three circuit breaker and three current transformers, which measure the
current and give protection. One isolator is used for generator protection it is
installed in start of the bay.
25. We also use the current transformer in Series of every bay. There are five coils
of CT and three basic purposes of using CT.
Measurementof the current.
Protection of the relays and breakers etc.
metering
for the breaker failure
5.1.5 POTENTIAL TRANSFORMER:
We also use the potential transformer in parallelof the bus bar. It is used to
measure the voltages and it has been installed with the bus barto measure
the voltage across the bus bar.
We are checking for high voltage and low voltage but carefully for the low voltage
because the auxiliaries which we are running from this voltage will draw very
high current if the voltage is very low and this can damage our equipment.
So, we keep on checking for the low voltage and the high voltage. We have to use
P.T. because we can’t design such a big voltmeter.
5.1.6 BUS BAR:
Now we discussed aboutthe bus bars we are using two busbars in GEPCO power
plant, first of all we will define bus bar
“Busbar is a conducting piece of barwhich connect among the source and
the distribution circuit”
It work as a medium between feeder and source. The busbar voltages remain
same. So the six feeders go out from the GEPCO powerplantof 220KV and thesix
are 132KV.
26. 5.1.7 Relays:
These are operated by taking information from C.T. and P.T. Each and every
thing of the system even in the switchyard is being protected by relays because
they are madevery much sensitive for the faults. They sense every fault for which
it has been designed and then some other important devices are operated from the
signalof the relay.
There are manytypes of the relays,
Differential over current relay.
Over current relay.
Over and undervoltage relay.
Differential over current relay.
27. Chapter 06
Battery Room
6.1 PURPOSE: The purpose of the battery room is to provide dc supply
needed for the relay action (mostly for protection purposes).
They are also source of excitation in case of blackout thud havevital use as
dc backup supply.
6.2 THE BATTERIES:
Outputvoltage of 220V
They are of led acid type having sulfuric acid (H2SO4)asthe electrolyte.
6.3 Ring System:
In Pakistan all Power station are interconnected through ring system NPCC is the
main head, which control all the power Stations, and tells control the process of
demand and supply. Mr. Ghulam Ishaq Khan, Presidentof Pakistan on 20 January
1990, inaugurated theNationalPower Control Centre Islamabad.Thisis first
phaseof the giantproject. It envisages implementation of the modern
computerized load dispatch facilities for operating WAPDA's power system, by
setting up of one NationalPower Control Centre (NPCC) atIslamabad and two
RegionalControl Centers at Islamabad andJamshorofor northern and southern
parts of the network respectively. The main functions of these Power Control
Centers are NationalPower Control Centre system ensures supply of energy to
every consumer at all times at rated voltage, frequency and specified waveform, at
lowest cost and minimum environmentaldegradation. Theswitchgear, protection
and network automation are integral parts of the modern energy management
system and nationaleconomy. Themodern 3-ph, 50 Hz, AC interconnected system
has several conventional and non-conventionalpower plants, EHV AC and HVDC
Transmission system, Back to Back HVDC coupling stations, HV Transmission
network, substations, MV and LV Distribution systems and connected electrical
loads. Theenergy in electrical form is supplied to various consumers located in
vast geographicalarea, instantly, automatically, and safely with required quality
at all times. The service continuity and high qualityof power supplyhave become
very important.
For fulfilling the foresaid purpose, a state of the art, scientifically and
28. technologically advanced SUBSTATION is required. Sub-Station is the load
control center of the thermalplantwhere power at rated voltage, frequency
and waveform is exported/imported as per requirements.
31. Chapter 07
Annual Shutdown (P&I)
In annualshutdowndifferent feeders are off becausethere is a transformer test like
transformer oil field test, if the transformer oil result is more than 50%then it is
useable, transformer buckle test, transformer insolation test, transformer breaker
test, control room relays test, current transformer and potential transformer test .
Some pictures during annualshutdown.
32.
33. Chapter 08
Neutral and Ground
Neutral:
A reference connection in a power distribution system.
Ground:
A connection to the earth or to a conductive object such as an equipment
chassis. There are two objectives to the intentionalgrounding of electrical
equipment:Keep potential voltage differentials between different parts of a
system at a minimum to reduce the shock hazard. • Keep impedanceof the
ground path to a minimum. Thelower the impedance, the greater the current is
in the event of a fault. Thegreater the current, the faster an over.
![INTERNSHIP REPORT [2015]
GEPCO INTERNSHIP REPORT
(15 July 2015 to 31 August 2015)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)