1. VACATION EMPLOYMENT REPORT
NAME: SIKANA KELVIN
COMPUTER NUMBER: 11016931
DEPARTMENT: EMERGENCY POWER AND MECHANICAL SYSTEMS
SUPERVISOR: MR MUBABE BWALYA
DURATION: FROM 19TH
AUGUST 2014 TO 26TH
SEPTEMBER 2014.
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I. Contents
II. EXECUTIVE SUMMARY.....................................................................................................................2
III. DEDICATIONS...................................................................................................................................3
IV. ACKNOWLEDGEMENT......................................................................................................................4
V. COPPERBELT ENERGY CORPORATION MISSION .............................................................................5
VI. COPPERBELT ENERGY VISION STATEMENT.......................................................................................5
VII. COPPERBELT ENERGY VALUES..........................................................................................................5
VIII. INTRODUCTION ...............................................................................................................................6
IX. EMERGENCY POWER AND MECHANICAL SYSTEMS DEPARTMENT....................................................8
X. FUNCTION OF EMERGENCY POWER AND MECHANICAL SYSTEMS DEPARTMENT.............................9
XI. REMOTE CONTROL THROUGH SCADAs SYSTEMS............................................................................10
Various process and analytical instrumentation ..........................................................................11
XII. DESCRIPTION OF A GAS TURBINE ALTERNATOR (GTA)....................................................................12
A. WORKING PRINICPLE OF A GAS TURBINE ALTERNATOR.............................................................14
XIII. GAS TURBINE ALTERNATOR AT McLAREN LUANSHYA.....................................................................17
XIV. COPPERBELT ENERGY GTA CONTROL PANELS.................................................................................18
XV. ENVIRONMENTAL IMPACT OF GTAs AND MONITORING.................................................................20
XVI. RESULTS OBTAINED FROM GAS ANALYZER AT McLAREN GTA LUANSHYA......................................21
XVII.FIRE PROTECTION AND SUPRESSION SYSTEMS AT CEC ...................................................................22
A. COPPERBELT ENERGY FIRE DETECTION SYSTEM .........................................................................22
B. THE DEVICES USED IN FIRE SUPRESSION AND OPERATION .........................................................23
C. HEAT SENSOR ............................................................................................................................24
D. SMOKE DETECTORS....................................................................................................................24
E. FIRE CONTROL PANEL ................................................................................................................25
F. CYLINDERS FOR FIRE PROTECTION SYSTEMS ..............................................................................26
XVIII.........................................................................MAINTAINANCE OF THE GAS TURBINE ALTERNATORS
28
XIX. RECOMMENDATION ......................................................................................................................30
XX. CONCLUSION.................................................................................................................................31
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II. EXECUTIVE SUMMARY
The purpose of this report is to fulfill the internship requirement for the bachelor’s degree in Electrical
Engineering. While I was working at Copperbelt Energy corporation, I worked at the department of
Emergency Power and Mechanical Systems under the section of Gas Turbine Alternator control (GTA)
and Instrumentation. Where I learnt the operations of the Gas Turbine Alternators (GTA), there
maintenance and system protection at Copperbelt Energy Corporation sites which were at McLaren GTA
in Luanshya, Luano GTA and substations in Chingola, Bancroft in Chilibombwe and Frontier in Ndola.
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III. DEDICATIONS
The dedication of this work is firstly, to God the father, the son and the Holy Spirit for the
unfailing and everlasting love towards me. Secondly, I dedicate this work to my parents Mr
Nahum Sikana and Mrs Fortunator Sikana whose words of encouragement and wisdom have
been a driving force to excellence in my endeavors.
Lastly, I dedicate this work to my brothers and sister who have given me the required support
throughout the entire period of my internship.
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IV. ACKNOWLEDGEMENT
The internship could not have been completed without the help and knowledge of different
sources of people through there working experiences at copperbelt Energy Corporation. I would
like to thank Section Engineer Mr Leonard Lufungulo for giving me an opportunity to work
under his section to gain the knowledge and experience that is required in the field of study. My
gratitude goes to my Foreman GTA Instrumentation Mr Bwalya Mubabe for his continuous
guidance in electronic devices and systems. My appreciation goes to Mr Mbindo kalowa, Mr
Nzima Mortforts, Mr Ngombe Philip, Mr Mayaba tresfird and Mr Mulenga Vincent for their
mentoring and advice in the Gas Turbine Alternators, Instrumentation and fire suppression
systems. I would like to give thanks to Mr Tiza kofi and Mrs Franchesca Malumbe for the help
rendered in acquiring the necessary information and practical application.
Last but not the least, and most importantly, I thank God and my family members who have been
on my side at all times and supportive during my attachments.
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V. COPPERBELT ENERGY CORPORATION MISSION
We are committed to supply reliable energy and high quality services to meet our
customer’s unique and changing needs sufficiently and proactively
Increase value for our shareholders
VI. COPPERBELT ENERGY VISION STATEMENT
To be the leading Zambian investor, Developer and operator of energy infrastructure in
Africa by providing innovative solutions and building strategic partnerships through
committed professional teams
VII. COPPERBELT ENERGY VALUES
Be honest in our dealings
Supporting each other
Building good team relationships
Being open to new ideas
Developing a’ can do’ attitude
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VIII. INTRODUCTION
The coppperbelt energy corporation’s core business is transmission and distribution of power
purchasd from state owned utility Zesco , to Zambia’s privitiized mining companies on the
copperbelt province. Copperbelt energy is a profitable , Zambian company which accownts for
approximately half of Zambia’s power sales, its core business consists of
Operation and maintaining a network comprising transmission , distribution and
generation assets and a control centre on the copperbelt
Supply secure and reliable power to copperbelt mining companies , which include the
provision of generation back up for mining company emergency power requirements
Wheeling power within and through the copperbelt for other users, principally ZESCO
Wheeling power internationally through interconnector with the DRC into the SAPP
Copperbelt energy corporation buys electrical energy from Zesco of which 25% is sold back
to Zesco and the 75% of the electricity Copperbelt Energy Corporation supplies it to its
customers. This agreement is effective until the year 2020, under this agreement , tarrifs are
adjusted annuallyin accordance the US,PPL. CEC also earns revenue from the operations of its
inter-connector with thr DRC and from wheeling power through the system for distribution by
ZESCO to its customers within and outside of the copperbelt. The major customers are the
mining companies on the copperbelt.
This electricity is received from Zesco at 330 KV, this is stepped down to 220KV, depending
on the systems of equipment of the recipient companies of the electricity , it is further stepped
down to 66KV, 33KV, 11KV, 3KV.
This electricity is used for the daily running of the companies, to pump out from underground
to reducing the flooding of the mines, it is used for ventilation in the mines by supplying oxygen
underground, since workers need to be transported from the surface to underground and vice
versa the electricity is supplied to the lifts to provide transport for the workers. The minerals as
well require to be transported from underground to the surface via hoists, electricity is supplied
to the hoists.
In the event that Zesco fails to supply or rather has a problem in delivering the power to
Copperbelt energy corporation, the company has eight (8) gas turbine alternators ( GTAs) all
around the copperbelt of which one is capable of producing about 10MW. These gas turbines
alternators are located in Chingola at Luano (has two GTAs), Mufulira in kankoyo, Luanshya at
McLaren, chililabombe at Bancroft (has to GTAs)
To meet the demand on power Copperbelt energy corporation, owns 835.7 Km of 220KV and
66KV transmission lines, 540 Km of optic fiber on power lines, 41 high voltage substations of
which there 36 major ones , electricity carrying capacity of 700MW and 80MW of gas turbine
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generation. To ensure high quality of supply, reliability enhancing features include a high degree
of network redundancy , standby generation, a well-equipped control center and multiple
electricity sourcing points at Kafue Gorge (Zesco power station) and one in the DRC through
interconnectors. CEC interconnects with Zesco at Luano and Kitwe 330/ 220KV substations.
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MANAGER
ELECTRICAL
ENGINEER
SENIOR
ASSISTANT
ENGINEER
FOREMAN
TECHNOLOGIST
TECHNICIAN
ARTISAN
MECHANICAL ENGINEER
SENIOR ASSISTANT
ENGINEER
FOREMAN
TECHNOLOGIST
TECHNICIAN ARTISAN
INSTRUMENTAION
ENGINEER
SENIOR
ASSISTANT
ENGINEER
FOREMAN
TECHNOLOGIST
TECHNICIAN ARTISAN
IX. EMERGENCY POWER AND MECHANICAL SYSTEMS DEPARTMENT
(1) DEPARTMENT STRUCTRE
In order for the department to function effectively and efficiently, the department has been
divided into fields with a specific function, this ensures co-ordination among workers and helps
establish team work.
The department is divided into sections , GTA Instrumentation, GTA electrical and GTA
mechanical these subdivided sections are headed by a manager who makes sure these sections
carry out all their works smoothly and orderly, each section is headed by a section engineer and
has an assistant called a senior assistant engineer, these two supervise works through the
foreman. The foreman implements these works through Technicians, Artisans and Technologists.
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X. FUNCTION OF EMERGENCY POWER AND MECHANICAL SYSTEMS
DEPARTMENT
Electricity is an important input for all forms of mining and households. It is a major source of
energy source for transport of personnel, materials and ore movement, production machines ,
mineral processing and equipment monitoring and protection systems. In addition it is an
exclusive power source for vital health and safety related applications such as the pumping of
water, ventilation and refrigeration.
ii) Since CEC receives is its electrical energy from Zesco, there times where Zesco fails
to supply CEC to supply the electrical energy due to faults or systems failures, CEC
under the department of Emergency Power and Mechanical Systems is obligated to
keep the supply of electrical energy to its customers this is accomplished through the
use of Gas Turbine Generators which are put on standby in the event such a situation
occurs. These machines can be turned on/off manually or can be turned on/off
remotely through the use of SCADAs. The customers have selected the loads to
supply power with in this emergency situation, but priority goes to the ventilation of
the ventilation systems, some underground mines are wet, therefore without power
they begin to flood, which in turn results to the loss of lives and the damaging of
mining equipment, therefore the CEC makes sure power goes to the pumps so that the
mines do not flood. Transportation of personnel from underground using lifts which
without power cannot operate. This situation is given a code name and is referred to
as a CAT3 situation. Therefore the department supplies emergency power.
iii) Demand control through peak lopping, this refers to a situation whereby the consumer
chooses to cut the peak demand that they require in order to avoid paying the
penalties associated.
iv) Power factor correction, the power factor of an ac electrical power system is defined
as the ratio of the real power flowing to the load, to the apparent power in the circuit.
Real power is the capacity of the circuit for performing work at a particular time,
apparent power is the product of the voltage and the current. In an electric power
system, a load with lower power factor draws more current than a load with a high
power factor for the same amount of useful power transferred. CEC does power factor
correction by running the generator separately without synchronizing it with the Avon
engine, this process is usually referred to as pushing in MVA. The alternator acts a
motor by using its inductive property. When the power factor is low causes high
currents to flow thereby becoming very costly as the system requires thicker wires
and systems that can handle high currents, therefore this is avoided by power factor
correction.
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XI. REMOTE CONTROL THROUGH SCADAs SYSTEMS
SCADA (supervisory control and data acquisition) is a system operating with coded signals
over communication channels so as to provide control of remote equipment (using typically one
communication channel per remote station). The supervisory system may be combined with a data
acquisition system by adding the use of coded signals over communication channels to acquire
information about the status of the remote equipment for display or for recording functions. It is a
type of industrial control systems (ICS).
A SCADA system usually consists of the following subsystems:
Remote terminal unit (RTUs) connect to sensors in the process and convert sensor
signals to digital data. They have telemetry hardware capable of sending digital
data to the supervisory system, as well as receiving digital commands from the
supervisory system. RTUs often have embedded control capabilities such as ladder
logic in order to accomplish boolean logic operations.
Programmable logic controller (PLCs) connects to sensors in the process and
converting sensor signals to digital data. PLCs have more sophisticated embedded
control capabilities, typically one or more IEC 61131-3 programming languages,
than RTUs. PLCs do not have telemetry hardware, although this functionality is
typically installed alongside them. PLCs are sometimes used in place of RTUs as
field devices because they are more economical, versatile, flexible, and
configurable.
A telemetry system is typically used to connect PLCs and RTUs with control
centers, data warehouses, and the enterprise. Examples of wired telemetry media
used in SCADA systems include leased telephone lines and WAN circuits.
Examples of wireless telemetry media used in SCADA systems include satellite
(VSAT), licensed and unlicensed radio, cellular and microwave.
A data acquisition server is a software service which uses industrial protocols to
connect software services, via telemetry, with field devices such as RTUs and
PLCs. It allows clients to access data from these field devices using standard
protocols.
A human–machine interface or HMI is the apparatus or device which presents
processed data to a human operator, and through this, the human operator monitors
and interacts with the process. The HMI is a client that requests data from a data
acquisition server.
A Historian is a software service which accumulates time-stamped data, boolean
events, and boolean alarms in a database which can be queried or used to populate
graphic trends in the HMI. The historian is a client that requests data from a data
acquisition server.
A supervisory (computer) system, gathering (acquiring) data on the process and
sending commands (control) to the SCADA system.
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Communication infrastructure connecting the supervisory system to the remote
terminal units.
Various process and analytical instrumentation
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A. WORKING PRINICPLE OF A GAS TURBINE ALTERNATOR
A gas turbine also called a combustion turbine., it is a type of internal combustion engine, the
engine takes in fresh air from the inlet, which flows through to the compressor, what really
happeans at the compression stage is that the volume of the air is reduced, the effect of the
reduction in volume is that, the particles will move faster in that space, thereby increasing the
kinetic energy of the air, since kinetic energy is related to the temperature, therefore rise in
kinetic energy causes rise in temperature and pressure, since for combustion to occur there must
be the presence of air (oxygen), a fuel (diesel) and fire, spark plug. Therefore after compression
has occurred the compressed air mixed with the fuel being diesel and then ignited to produce
energy, this generates a high temperature flow. This high temperature high pressure enters the
turbines in form of a gas, some of the gas is expelled through the exhaust and some pressure is
used to drive the turbine.
The turbine has a rotor, this rotor has field windings attached to it, field windings these are
electrically conducting circuits, usually a number of coils would on individual poles and
connected in series, that produce a magnetic field in a generator.an alternator also contains a
stator this contains armature windings, armature winding are the main current carrying windings
the electromotive force or counter emf of rotation are induced.
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For the system to run effieciently and effectively there generator speed should synchronize
with the turbine speed.What happens is that when the turbine is turning, it turns the rotor, the
rotor is like a flywheel having alternating N and S poles fixed in the outer rim, the magnetic
poles are excited (or magnetized) from direct current supplied from a dc source. In most cases ,
necessary excitation current is obtained from a small DC shunt generator which is belt or
mounted on the shaft of an alternator itself. When the rotor rotates , the stator conducts (being
stationary) are cut by the magnetic flux, hence they induce e.m.f and hence current in armature
conducts , which flows in one direction and then in the other. Hence , an alternating e.m.f is
produced in the stator conductors, whose frequency depends on the number of N and S poles
moving past a conductor in one second. This induced current alternating current is transmitted in
a 3 phase system into the GTA grid for consumption by customers.
The transmission and distribution of the electrical energy is done through overhead transmission
lines which run all over the copperbelt and are continuous maintained by copperbelt energy
corporation.
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XIV. COPPERBELT ENERGY GTA CONTROL PANELS
GTA DIRECT CURRENT (DC) CONTROL PANEL
GTA ALTERNATING CURRENT (AC) CONTROL PANEL
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HUMAN MACHINE INTERFACE , ANALOGUE SYSTEM DISPLAY AND PLCs
CONTROL PANEL
GTA SCREEN DISPLAY ON HUMAN MACHINE INTERFACE
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XV. ENVIRONMENTAL IMPACT OF GTAs AND MONITORING
Gas turbine alternators use fossil fuels which are the largest greenhouse emitters in t2he world
contributing to ¾ of all carbon dioxide, methane, and other greenhouse gas emissions , burning
coal, petroleum and other fossil fuels at extremely high temperatures( combustion) is the primary
means by which electricity is produced, but leads to heavy concentrations of pollution in our air
and water. CEC monitors gas emissions of their gas turbines under the section of
instrumentation, and are assessed if at all they are producing a high pollution on the
environment, such checks are done using a gas analyzer
.
A probe is connected to the gas analyzer which is inserted into a small pipe/ tube where the gas
enters and is analyzed, this process takes a few minutes, because the equipment is already
calibrated, to indicate the amount of emissions the gas turbine releases into the environment and
these finding are further submitted
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XVI. RESULTS OBTAINED FROM GAS ANALYZER AT McLAREN GTA
LUANSHYA
REULTS FROM GAS ANALYZER SLIP
THE MAGNITUDE OF EMISSIONS ARE COMPARED BY
COMPARISON.
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XVII. FIRE PROTECTION AND SUPRESSION SYSTEMS AT CEC
Fire protection systems are those systems put in place to prevent or mitigate the unwanted effects
of fire. Fire can cause damage to equipment and most these equipment’s are too expensive and
can take a really long time to replace hence slowing down production and the efficiency of the
company, it can also be responsible loss of lives. The aim of these fire suppression systems is to
detect any form of fire, even of the smallest magnitude and take the necessary responses to
prevent it from spreading and quenching it before it becomes a problem for both equipment’s
and human lives.
A. COPPERBELT ENERGY FIRE DETECTION SYSTEM
Since a fire is identified by three main components which are, smoke, heat and light, these
detections can be used as inputs to detect a fire .The copperbelt energy corporation uses smoke
and heat detectors to detect the presence of a fire.
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Each zone has a heat and smoke detector which make up one knock (input), a knock can only
be considered as a fire if and only if both the smoke detector and heat detector in a zone have
verified the presence of a fire.
BEHAVIOUR OF ZONE WHEN COMFIRMING FIRE IN ONE ZONE BY DETECTORS
INPUT SMOKE DETECTOR INPUT HEAT DETECTOR OUTPUT FOR ZONE
0 0 0
0 1 0
1 0 0
1 1 1
The behavior looks like that of an AND GATE integrated IC when a fire is confirmed in one
zone the bell rings and the air ventilation systems are should down ( this is to prevent oxygen
from further fueling the fire), this bell is used to confirm that a fire has been detected and if there
is any personnel in the affected zone or area they a required by protocol to rush through the
emergency exit doors, to the fire assembly point, when the second fire is picked up in another
zone, the siren is activated, this siren gives an indication that the gas will soon be released in
those zones and it is given a time delay of 30 seconds before being delivered to the zones, in that
time all personnel should have exited the buildings.
B. THE DEVICES USED IN FIRE SUPRESSION AND OPERATION
MANUAL CALL POINT (RED IN COLOUR)
This is used when you want to warn personnel in the building of the presence of a fire, this is
activated by breaking the glass on the manual call point. This immediately sounds the bell.
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MANUAL CALL POINT (YELLOW IN COLOUR)
This is only activated when you want the gas to be released to the affected zones by the fire, this
is activated by breaking the glass, on the gas control unit.
C. HEAT SENSOR
This detects fire, or rather responds when the temperature reaches 57 degrees Celsius, this
operates when the heat sensitivity eutectic alloy reaches a point changing state from solid to
liquid. Thermal lag delays the accumulation of heat at the sensitive element so that the fixed
temperature device will reach its operating temperature, sometimes after the surrounding
temperature exceeds that temperature and sends an input signal, this is electrically connected to
control panel
D. SMOKE DETECTORS
A smoke detector is a device that senses smoke, typically as an indicator of a fire. These are of
two types optical and ionization smoke detectors used by copperbelt energy corporation.
IONIZATION SMOKE DETECTOR
Ionization smoke detector contains a small amount of radioactive material , americium
embedded in the gold foil, this gold americium foil is then sandwiched between a thick silver
backing and a palladium laminate, this is enough to completely retain the radioactive material
but enough to allow the alpha particle to pass,
The ionization chamber is basically a two metal plates a small distance apart. One of the plates
carries a positive charge, the other a negative charge, between the two plates , air molecules
made up mostly of oxygen and nitrogen atoms are ionized when electrons are kicked out of the
molecule by alpha particles from the radioactive material (alpha particles are big and heavy
compared to electrons). The result is oxygen and nitrogen atoms that are positively charged
because of one short electron, the free electrons are negatively charged.
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The positively charged atoms flow towards the negative plates, as the negative electrons flow
towards the positive plate. The movement of the electrons registers as a small but steady flow of
current. When smoke enters the ionization chamber, the current is disrupted as the smoke
particles attach to the charged ions and restores them to a neutral electrical state. This reduces the
flow of electricity between the two plates in the ionization chamber, when the electric current
drops below a certain threshold, the alarm is triggered.
OPTIC/PHOTOELECTIC SMOKE DETECTOR
Optical smoke detectors, also referred to as photoelectric smoke detectors, use a light source to
detect smoke. The Infra –Red LED is a lens that shots a beam over a large area. If smoke is
present in the room. It enters the optical chamber, having smoke particles scatter and sensor sets
of the alarm.
E. FIRE CONTROL PANEL
This is where all the processes are communicated in the fire protection and suppression system,
this is also where all the controls are located, it indicates, which zone(s) have a fault, where the
fire is being detected, which areas are isolated, the sirens, bells alarm system, it more like the
command center for the fire protection system.
EXTERIOR OF CONTROL PANEL INTERIOR OF CONTROL PANEL;
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In the event that there is a CAT3 situation and there was no power supply to the fire suppression
system, there are DC batteries to back the system up in such a situation, therefore the fire
protection system is always active.
F. CYLINDERS FOR FIRE PROTECTION SYSTEMS
These are the gases that are used to suppress the fire , the main gases used are Carbon dioxide,
FM 200, HCF, FM 200 is used where people occupy spaces, so as not to have any human lives
lost in the event of a fire.
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XVIII. MAINTAINANCE OF THE GAS TURBINE ALTERNATORS
There are two types of maintenance, these are Preventive maintenance and Routine maintenance.
PREVENTIVE MAINTENANCE
This is done every two weeks in all gas turbine plants. It involves checking for any problem that
may arise either in control room, pump house or turbine hall and is the time for good
housekeeping of the GTA plant.
PURPOSE OF PREVENTIVE MAINTENANCE
I. To check the equipment if it has at all any faults
Listed below are Instrumentation equipment’s
a) AVR panel
b) Local control panel (LCP) indication and Enunciator panel
c) Generator protection panel
d) Bently Nevada 3500 vibration equipment
e) Auto synchronize
f) Temperature indicator
g) Invertor
h) Local control panel (LCP) human machine interface (HMI)
i) Pressure gauge and transmitter
ROUTINE MAINTENANCE
The maintenance is conducted every three months and it involves all three sections from
emergency power, instrumentation, electrical and mechanical
THE INSTRUMENTATION SECTION
Ensure that flow control transmitters, pressure m transmitters, flow and indicators are all
working correctly and are in good condition
THE MECHANICAL SECTION
Ensures that there are no leakages (lubrication oil system is operating okay) both the AC and the
DC pump, that pump the fuel to the Avon air filter are clean, if not are changed.
THE ELECTRICAL SECTION
Ensures that all electrical motors both AC and DC is in good condition , the transformer oil being
used is okay and no leakages are found on the GTA.
Below is the check list of instrumentation equipment
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a) Reactive power indicator
b) Active power indicator
c) Power factor indicator
d) Gas generator speed indicator
e) Power turbine speed indicator
f) GG exhaust gas temperature (EGT) indicator
g) Excitation voltage indicator
h) System frequency indicator
i) Generator voltage indicator
j) Generator current indicator
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XIX. RECOMMENDATION
In the one month I have been with the emergency power and mechanical system, I have found
that there is a great need for the University of Zambia, School of Engineering under the
department of Electrical and Electronic Department and Copperbelt energy corporation to
partner in helping student get insight in technological advances that the company is using in
electricity distribution and transmission as well power generation systems
In the fire system protection, there is a great need for Copperbelt energy cooperation, to install
sensors that will be able to detect the presence of people in the zone where there still some
personnel working especially for gases like Carbon dioxide before the cylinders are detonated
especially in the turbine halls.
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XX. CONCLUSION
The vacation employment was impactful; it helped realize the practicality of electrical and
electronic engineering, it brought about the exposure to electrical power generation, transmission
and distribution, the use of digital electronics in the applications of Programmable logical
controllers, in telemetry and how a power plant operates and the importance of instruments for
data analysis
