Chapter One
Background of EEP
1.1 History of EEP
Electric power was introduced to Ethiopia in the late 19th century, during the regime of Minilik. The
first generator was given to Atse Minilik around the 1898 to give light to the palace. In addition to the
use of generator, Atse Minilik constructed the first Hydro Power Plant on Akaki River in the year 1912 in
order to supply power to small factories that had been established in Addis Ababa. Consequently, the
power supply that had been limited to small factories, the palace and it was extended to the public
places and major roads in the vicinity of the palace. During this temporary occupation, the Italian
company called Coneil overtook the generation and distribution of electric power. The company
installed generators at different places and extended the power supply to the major towns. After the
Italian were driven out from Ethiopia in the year1941, an organization called Enemy Property
Administration was established and took over along with other activities the generation and
distribution of power to the public. In the year1948, an organization that had been vested with the
enemy property was evolved to an organization called Shewa Electric Power. This also with limited
capacity, managed to increase the power supply not only in Shewa but also other administrative regions.
In light of its function, its name was changed “Ethiopian Electric Light and Power” in the 1955. Soon
after its establishment, the supervision and management of the organization was vested in the Board of
Directors appointed by the government. After eight months of its establishment the Ethiopia Electric
light and power was transformed to the “Ethiopian Electric Light and power Authority”. The authority
was engaged in the business of producing, transmitting, distributing and selling of electric energy to the
people of Ethiopia and carry on any other lawful business incidentals or appropriate which is calculated
directly or indirectly to promote the interest of the authority or to enhance the value of its properties.
At that time the annual electricity production capacity of the authority was 35 GHz while the number of
customer was 12,500. One of the major changes in the economic sector was the transformation of
centralized command economy to the free market driven economy in the 1987.In order to
accommodate the new changes in the environment, the Ethiopia Electric light and Power Authority was
transformed to the Ethiopian Electric Power Corporation (EEPCo) in 1997 as public enterprise was
established for indefinite duration by regulation No.18/1997, and conferred with the power Authority.
The purpose of the corporation is to engage in the business of producing, transmitting, distributing and
selling electric energy in accordance with economic and social development policies and priorities of the
government and to carry on any other related activities that would enable it achieve its purpose.
Currently the annual electricity production capacity of the corporation is about 3112 GWH and number
of customer 1.1 million. The corporation has been increasing the number of customers by more than
15% annually, but this does not mean that the corporation has met demand for electric power. EEPCo is
required to think and work strategically to meet the power supply need of the socio-economy
development of country. The corporation has two electric power supplying systems: The Interconnected
System (ICS) and Self Contained System (SCS). The main energy source of ICS is hydropower plant, and
for the SCS mini-hydro and a number of isolated diesels power generators allocated in various areas of
the country are the energy sources. EEPCo is a government owned corporation and it has two
organizations one of this, EEP which is responsible for the generation, transmission service of electric
energy throughout Ethiopia. The second organization is Ethiopian Electric Utility (EEU) which is
responsible for distributing and selling power to customers. However, Dangila substation is installed in
1976 E.C, which is found in North West region of Amahara.
1.1.1
Vision, Mission, and Purpose of EEP’s Establishment
Vision
to be a first class providing quality universal electrification of the country and regionally connected as a
competitive export industry.
Mission
to provide adequate and quality electricity generation, transmission through continuous improvement
of management practice responsive to the socio-economic development and environmental protection
need of the public.
The purposes for which EEP is established are;
To undertake feasibility studies, design and survey of electricity generation, transmission and
substation; to contract out such activities to consultants as required; to undertake electricity generation,
transmission and substation construction and upgrading;





To contract out such works to contractors as required;
To handle electricity generation and transmission operational and maintenance activities.
To lease electricity transmission lines as required;
To sell bulk electric power;
To undertake universal electric access works;
In line with directives and policy guidelines issued by the Ministry of Finance and Economic
Development, to sell and pledge bonds and to negotiate and sign loan agreements with local and
international financial sources;
 To undertake any other related activities necessary for the attainment of its purposes.
1.2 Main Products and Services of EEP
EEP produces electric power from hydropower, diesel, geothermal, wind, solar, natural gas, biomass and
coal plants that provides the service of selling the electric power to its customers mainly the Ethiopian
people for house hold uses, factories, and the nearby countries like Kenya, Sudan, and Djibouti.
1.3 Main Customers of EEP
Numbers of customers are those who are connected to the electric energy produced from generation
station. The total number of connected customers at present is 1,900,000. Note: All our data about
EEP’s products, customers, and overall energy situations are up to 2012 GC
Table 1.1: Total numbers of customers .
Tariff group
2007\08
2008\09
2009\10
2010\11
2011\12
Domestic
144,304
144,304
1,649,062
1,652,310
1652,062
Commercial
Street light
Industrial LV
207,986
3,060
22,908
207,986
3,260
22,908
222,308
2,690
20,199
222,746
2,695
20,199
222,746
2,695
20,199
Industrial HV
242
242
149
149
149
1834
1900
1,900
1,900
Own
1834
consumption
1.3.1 Interconnection
Ethiopia is focusing on the development of the huge hydro potential it possesses in the Eastern African
Region. To get the required economy of scale to develop the big hydropower sites in Ethiopia, it is
compulsory to seek foreign demands for export purposes, especially, neighboring countries of Sudan,
Egypt, Djibouti, Yemen, Kenya, Eritrea, and Somalia. There are current and potential interconnections.
Ethiopia-Sudan (Current Interconnections) Currently, Ethiopia is supplying 100MW of power to Sudan A
link of double circuit 230 KV with transfer capacity of about 400 MW is Constructed. The link starts from
Bahir Dar
BDU/BiT/FECE Page | 4 substation passing through Gondar and Shehedi substations in Ethiopia and ends
at Gedaref substation in Sudan with a total length of 296 km(from Shehedi to gedarif) . Ethiopia-Djibouti
(Current Interconnections) Currently, Ethiopia is supplying 60MW of power to Djibouti a link of Double
circuit 230 KV with transfer capacity of about 400 MW is Construct .The link starts from Dire Dawa
substation in Ethiopia and ends at PK-12 substation in Djibouti with a total length of 283 km. EthiopiaKenya (Potential Interconnections) the export will, possibly, be based on firm energy. The link may start
from Gilgel Gibe-III power plant and passes through Mega substation in Ethiopia and ends at the towns
of Nairobi or Eldorate in Kenya. The link from Gilgel Gibe-III to Mega will be double circuit 400 KV HVAC.
HVDC link of at least 500 KV with transfer capacity of about 600 MW is anticipated from Mega
substation to Kenya (Nairobi or Eldorate)
1.4 Organizational structure of EEP
Management Board
Corporate Ethic and Anti
Corruption
Internal Audit
Chief Executive Officer
Corporate legal affair
Corporate planning
Corporate communication
Generation
Construction
Transmission and
Substation
Construction
Generation
Operation
Distribution system
Design and
Construction Case
team
UEAP
Transmission
operation
Corporate
Finance and
supply team
Corporate
and sales
Marketing and
sales
Figure 1.1: The Over All Organizational Structure of EEP
Under Engineering division there are four subdivisions which are redefined after the establishment of
EEP enterprise.
Figure 1.2: Block diagram of engineering structural organization
Servic
e
1.5 Work Flow in EEP
EEP is responsible for generating, transmitting, distributing and selling of electric energy throughout
the country. To fulfill this company, use a wide and interconnected work flow therefore by using
different mechanism power will be generated and this will be transmitted and will be distributed for
customers. We must consider this all system is interconnected by a system which is called load
dispatch center (LDC).
1.5.1 Generation Stations and Current Energy Situation
Ethiopia is a country endowed with abundant, natural recourses such as Hydro power; Geothermal,
natural gas, solar and wind energy etc. that could generate surplus electricity. Among these only
Hydro powers potential of the country is estimated to be up to 45,000 MW. Since almost all the
listed resources not yet tapped the prevailing energy source that constitutes about 94.1 is biomass.
The rest are petroleum 5.2% and electricity 0.8%.
Supply system: - The Ethiopian electric power corporation (EEP) is a sole electricity power supplier
in the country. The corporation has two electric energy supply system. These are the interconnected
system (ICS) and the self-contained system (SCS). The main energy source of ICS is hydro and also
the SCS are mini hydrous and diesel power generators allocated in various areas of the country. For
the record, most diesel power Generators are becoming out of service because they are too much
costly with little amount of power.
Inter Connected System (ICS): -The ICS consists of 12 hydro, 11 diesel standbys, one geothermal
and two wind from power plants with installed capacity of 1939.6MW, 112.3MW, 7.30MW and
81MW respectively which brought a total of 2140.2MW.
Self-Contained System (SCS): -The SCS consists of three small hydro and several diesel power
plants. Generation in this System is mainly by diesel power plants having an aggregate capacity of
26.80MW.The contribution from the small hydro power plants is only 6.15MW.
Page | 6 Self-Contained System (SCS): -The SCS consists of three small hydro and several diesel
power plants. Generation in this System is mainly by diesel power plants having an aggregate
capacity of 26.80MW.The contribution from the small hydro power plants is only 6.15MW.
1.5.2 Transmission and Substation
The electric energy generated from the main hydro power plants is transported through high
Voltage transmission lines rated 45, 66,132,230,400KV.The total length of the existing
Transmission lines is about 11,796.32 Km. the existing transmission lines status by voltage level is
categorized. Supply of the distribution network is provided by step down substation connected to
the respective transmission and sub-transmission voltages. Totally there are 143 substations of
which 127 are supplying the distribution system the rest 16 are located by the power house areas
(switch yard).The existing substation located in different areas of the country based on their voltage
level are categorized as:
Table 1.2: Transmission network distance (km) divide by voltage level.
Year
400kV
230KV
132KV
66KV
45KV
Total
2007/08
-
2,175.00
3,983.25
2,234.60
475.93
8,868.78
2008/09
-
2,175.00
3,983.25
2,234.60
475.93
8,868.78
2009/10
211.38
2,235.02
4,170.69
2,234.60
30.15
9,281.8
2010/11
686.701
3,550.90
4,033.21
2,234.60
475.93
10,981.34
2011/12
686.701
4,222.976
4,658.417
1,973.136
1,973.136
11,796.32
Table 1. 3: Distribution substations divided by voltage level
Year
400kV
230KV
132KV
66KV
45KV
Total
2007/08
-
12
55
30
23
120
2008/09
-
12
55
30
23
120
2009/10
-
12
55
30
23
120
2010/11
2
14
56
30
23
123
2011/12
5
17
57
30
30
127
1.5.3 Distribution
Power distribution is both ICS and SCS is effected at primary voltage of 33, and 15KV.Consisting
entirely of 3-phases, 3-wire feeders and is stepped down to a utilization voltage of 380\220 (3phase, 4-wire) using 3-phase transformers to customer’s level.
Chapter Two
Overall Internship Experience
2.1. Objectives of the Internship
An internship program has its own general and specific objectives. Both objectives are very
essential to get enough educated and skilled man power in all aspects of Engineering.
2.1.1. General Objective
Bahir Dar Institute of Technology targeted this internship program can enable Engineering
students at their faculty to relate their theoretical knowledge gained from their department to
practical knowledge, and develop their profession skills.
2.1.2. Specific Objectives
Intern students during internship program are aimed on
Improving their theoretical, practical, professional, industrial problem solving capability,
Developing interpersonal communication skills, team playing and leadership.
Also, knowing, understanding, practicing work ethics
Adapting and developing work environment conditions are also parts of specific
Objectives of internship.
2.2. How Do We Get in To the Company?
After we have taken the request paper of internship paper from the Industrial linkage of Bahir
Dar University Institute of technology at the end of June 2008 E.C, we distribute the request
paper to many companies related to our department. From those companies, Ethiopian Electric
Power Corporation, were the first company which accepted our requesting internship paper for
four months starting from February 15 to June 15 of 2009 E.C. and they announced us by calling
cell phone to Bahir Dar University Institute of technology industrial linkage. After we got the
phone number of the company from the EEP, and they told us that EEP is divided in to two main
organizations, Ethiopian Electric Utility and Ethiopian Electric Power then informed us that ours
name list is on Ethiopian Electric Power. And we submitted it to the wire business office, and
then we met Mr.Shimels, manager of wire business office at Bahir Dar and he welcomed us
tenderly and explains what their office performs and looks like. And he informed us that we are
going to stay the internship period at Super vision and design sub department and he gave us
paper that have been submitted to the supervision office with best wishes. Finally we met
Mr.Giwon, manager of the supervision office at Dangila substation, he welcomed us with full of
kindness and explained what we will work on the internship period and informed us that we will
be with his office for the next four months and introduces us to Mr. Fekadie, Mr. Serawdink and
other stuff members and we start our intern with eager on February 15. But to get this placement
in the company it was tedious we were spending a lot of times come and backs.
2.3. Work Section that we have been working
Dangila substation receives power from one incoming line. This incoming line is Gordema
substation (main supply from beles), so receives 66KV. The incoming 66KV stepped down into
66/33kv, 66/15kv (feeders). Gordema substation (No: 2 substation in Bahir Dar) receives power
mainly from two generations, Tis -sat and Tana Beles 132kv and 400kv respectively. In addition
to this the substation can be received or send through Alamata and Mota lines. Hence, Gordema
substation can be considered as ring system. Ring system is a system that can be received and
sent. In substation 400kv from beles step down into national grid (230kv) and then distributes
into the outgoing lines, these are Gonder-1,Gonder-2,Alamata,Mota and 400kv into markos,66kv
into Bahir Dar No:1 substation and Dangla as well as 33kv into Adet. Since Ethiopian Electric
Power Corporation, EEP is associated with generation, transmission and distribution system. In
fact that after the power is generated; it has to be distributed to the customers through high
voltage transmission lines. But it is impossible to provide the generated power from generation
station directly to the customer due to different reasons. The first and main reason is voltage
drop, because the voltage drop will be high when the transmission line becomes longer and
longer. So that substations have a great role to solve the occurrence of this problem. Since most
of distributions’ fault are occurred due to over loading and due to lacking of ability of
transmission lines to carry the required power when they are designed and constructed. So, we
selected this work section to solve such problems. As a result, customers such as residents,
companies, real estates, factories and interconnected countries can get enough and suitable
power.
2.4. Overall System Components and Operation
2.4.1. Transmission Line Design Considerations
An overhead transmission lines consists of conductors, insulators, support structures, and in most
cases, shield wires.
a) Conductors
Aluminum is the most common conductor metal for overhead transmission than copper, due to
its lower cost and lighter in weight properties, and its abundant whereas copper is limited. Most
common Al conductors are
All-Aluminum Conductor, AAC.
All-Aluminum Alloy Conductor, AAAC.
Aluminum Conductor Alloy Reinforced, ACAR.
Aluminum Conductor Steel Reinforced, ACSR.
From those Al conductors, Aluminum Conductor Steel Reinforced, ACSR, is the most common
conductor type, which consists of layers of Al strands surrounding a central core of steel strands.
Stranded conductors are easier to manufacture, since larger conductor size can be obtained by
simply adding successive layers of strands. Stranded conductors are also easier to handle and
more flexible than solid conductors, especially in large size. The use of steel strands gives ACSR
conductors a high strength to weight ratio, and for the purpose of heat dissipation, overhead lines
are bare (no insulator cover).EHV lines often have more than one conductor per phase, these
conductors are called a bundle. Bundle conductors have a lower electric field strength of the
conductor surfaces, thereby controlling corona. They also have a smaller series reactance.
b) Insulators
Insulators provide electrical insulation between live conductors and earthed structures under
operating and over voltage conditions. Insulators are mainly made of either glazed, porcelain, or
toughened glass.
Most Commonly used Types of Insulators are;
• Pin type
• Suspension type
• Strain insulator and
• Shackle insulator
Pin Type Insulators
Pin type insulators are used for transmission and distribution of electric power at voltages up to
33 KV. Beyond operating voltage of 33 KV, the pin type insulators become too bulky and hence
uneconomical.
Figure 2.1: Pin type insulator
Suspension Type Insulators
For high voltages (greater than 33 KV), it is mostly used suspension type insulators shown in
figure below, which consists of a number of porcelain discs connected in series by metal links in
the form of a string.
Figure 2.2:Suspension type insulator
Stain Insulators
When there is a dead end of the line or there is corner or sharp curve, the line is subjected to
greater tension. In order to relive the line of excessive tension, strain insulators are used. For
low voltage lines (less than 11 KV), shackle insulators are used as strain insulators. However, for
high voltage transmission lines, strain insulators consist of assembly of suspension insulators as
shown in figure below.
Figure 2.3:Strain type insulator