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 I thankour guideALLAH for giving me the opportunity to study at An-Najah
University and I thank my family for supporting me in every moment
whether it was bad or good.
 I also admit the hard work that have been done from my supervisor and
every doctor that I had the owner to study between their hands specially
doctor Maher Khammash and I hope to pay bake the favor for all of you,
whether in my work or in my country or even in any other country ,thankyou
all.

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This report was written by student at the Electrical Engineering Department,
Faculty of Engineering, An-Najah National University. It has not been altered or
corrected. Other than editorial corrections, as a result of assessment and it may
contain languageas well as content errors. The views expressed in it together with
any outcomes and recommendations are solely those of the students. An-Najah
National University accepts no responsibility or liability for the consequences of
this report being used for a purpose other than the purpose for which it was
commissioned.

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List of Contents
 List of contents ………………………………………………….………….…… 1
 List of figures ……………………………………………………………..…… 2
 List of tables ……………………………………………………….........….... 3
 Abstract …………………………………………………………..…….…… 4
 The one-line diagram …………………………………………….………..….…. 5
 1.1 General introduction …………………………………………..………….…..8
 1.2 Description of Ramallah network ………………………………………….….9
 1.3 Substation ………………………………………………………….……….…10
 1.4 Elements of network ……………………………………………..……….….. 11
 1.5 Load categories ……………………………………………………..…….….. 12
 1.6 Introduction to power system protection …………………………..……….… 12
 1.7 Constrains ……………………………………………………….……………. 16
 1.8 Standard /Code …………………………………………………………….…. 16
 1.9 Methodology …………………………………………………………………..17
 2.1 Analysis of maximum condition …………………………….……………….. 18
 2.2 Maximum improved condition ……………………………..………………… 22
 2.3 Maximum condition results …………………………..…………..……….…..26
 3.1 Analysis of minimum condition ………………………………….…………...28
 3.2 Minimum improved condition ………………………………………..……….32
 3.3 Minimum condition results ………….………….…………………...………..36
 4. Power system protection calculation..……………….……………………..…..38
 5. Economical study ….………………….…………………………….….……….45
 Conclusion and recommendation ………………………………………………….47
 Appendix …………………………………………………………………………..48

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List of Figures
 Fig “1.0” : one line diagram …………………………………………………7
 Fig “2.1”: Singel ,deer Jreer and biteen substation ………………………….18
 Fig “2.2”: Tahounah ,Ramallah north substation ……………………………19
 Fig “2.3”: Silvana ,Ramallah city and Kharbatha station ……………………19
 Fig “2.4”: Al-moalmeen substation ………………………………………….20
 Fig “2.5”: Nabi-Saleh substation …………………………………………….21
 Fig “2.6”: Atarot main con. point ……………………………………………21
 Fig “2.7”: improved Singel, deer Jreer and biteen sub. ………………………22
 Fig “2.8”: imp. Tahounah, Ramallah north sub. ……………………………..23
 Fig “2.9”: imp. Atarot main con. point ……………………………………….23
 Fig “2.10”: imp. Silvana, Ramallah city sub. ………………………………...24
 Fig “2.11”: imp. Moalmeen sub. ……………………………………………..25
 Fig “2.12”: imp. Nabi-Saleh sub. …………………………………………..…25
 Fig “3.1”: Singel ,deer Jreer and biteen substation ………………………….28
 Fig “3.2”: Tahounah ,Ramallah north substation ……………………………29
 Fig “3.3”: Silvana ,Ramallah city and Kharbatha station ……………………29
 Fig “3.4”: Al-moalmeen substation ………………………………………….30
 Fig “3.5”: Nabi-Saleh substation …………………………………………….30
 Fig “3.6”: Atarot main con. point ……………………………………………31
 Fig “3.7”: improved Singel, deer Jreer and biteen sub. ………………………32
 Fig “3.8”: imp. Tahounah, Ramallah north sub. ……………………………..33
 Fig “3.9”: imp. Atarot main con. point ……………………………………….33
 Fig “3.10”: imp. Silvana, Ramallah city sub. ………………………………...34
 Fig “3.11”: imp. Moalmeen sub. ……………………………………………..35
 Fig “3.12”: imp. Nabi-Saleh sub. …………………………………………..…35
 Fig “4.1”: Nabi-Saleh Tr-r. before protection …………………………………39
 Fig “4.2”: Nabi-Saleh Tr-r. after protection …………………………………..41
 Fig “4.3”: Moalmeen sub. before protection ………………………………….42
 Fig “4.4”: Moalmeen sub. after protection ……………………………………44

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List of Tables
 Table “1.1”: Rating of power transformers …………………………….…..11
 Table “1.2”: Load category …………………………………………….…..12
 Table “2.1”: The voltages before and after imp. the max cond. …………….26
 Table “2.2”: The power factor before and after imp the max …………...…27
 Table “2.3”: The total demand and losses for max cond. ……….……….…27
 Table “3.1”: The voltages before and after imp. the max cond. …..…...…..36
 Table “3.2”: The power factor before and after imp the max ……….…..…37
 Table “3.3”: The total demand and losses for max cond. …………….……37

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Abstract
The important aspects to be covered in this project are preparing the initial data for Ramallah &
Al-Bireh Governoratenetwork and subject to a load flow study using modern software like ETAP
to improve the voltage level and reduce the electrical losses in the network by improving the
power factor and increase the reliability of the network and deals with the protection of network.
 The objectives of the project are:
 To be familiar with Ramallah & Al-Bireh Governoratenetwork.
 To improve the voltage level and decrease the real power losses.
 To get an economic benefits.
 To increase the reliability of the network.
 To keep the network protected and stable by isolating only the components those are
under fault.
 In order to do these objectives these method will be followed:
 Built the line diagram for ETAP program.
 Collect the data for the network including all parameters.
 Load flow analysis and study for network under (max. min. and fault condition).
 Voltage control of the network by using T.F and reactive power sources.
 Increase the capability of the transformer and transmission line.
 Using the protective relay or circuit breaker or by using the batteries to keep the network
stable and under protection.
The idea of this project is known but its applied with different way by using modern software’s
and solving some real practical problems from which this network suffer by the cooperation
‘’Jerusalem District Electricity Company –‘JDECO’ which gives us the help we need to take any
decision to develop the network.

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The one line diagram
Fig 1.0

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1.1 Introduction
In power engineering, the power flow study, also known as load-flow study, is an important
tool involving numerical analysis applied to a power system. A power flow study usually uses
simplified notation such as a one-line diagram and per-unit system, and focuses on various forms
of AC power (i.e.: voltages, voltage angles, real power and reactive power). It analyzes the
power systems in normal steady-state operation. A number of software implementations of
power flow studies exist.
In addition to a power flow study, sometimes called the base case, many software
implementations perform other types of analysis, such as short-circuit fault analysis, stability
studies (transient & steady-state), unit commitment and economic load dispatch analysis. In
particular, some programs use linear programming to find the optimal power flow, the conditions
which give the lowest cost per kilo watt hour delivered.
Power flow or load-flow studies are important for planning future expansion of power
systems as well as in determining the best operation of existing systems. The principal
information obtained from the power flow study is the magnitude and phase angle of the voltage
at each bus, and the real and reactive power flowing in each line.
Commercial power systems are usually too large to allow for hand solution of the power
flow. Special purpose network analyzers were built between 1929 and the early 1960s to provide
laboratory models of power systems; large-scale digital computers replaced the analog methods.
The Power system is complicated electrical networks used to supply, transmit, and use electrical
energy. The networks that supply’s towns containing houses hospitals industrial region called the
GRID. The grid contains generators that supply the power, the transmission system that carries
the power from the generating centers to the load centers and the distribution system that feeds
the power to nearby homes and industries. The majority of these systems rely upon three-phase
AC power - the standard for large-scale power transmission and distribution across the modern
world. Specialized power systems that do not always rely upon three-phase AC power are found
in aircraft, electric rail systems, ocean liners and automobiles.

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1.2 Description of Ramallah network
About Al-Quds electricalcompany
Covering the concession area company is currently approximately 25% of the West Bank and the
equivalent of 366 square kilometers distributed as follows:
Jerusalemarea
47 villages and covers an area of 82 square kilometers (not including, of course, Jerusalem was
occupied in 1948)
Ramallah area: of the 72 villages and covers an area of 174 square kilometers.
The Bethlehem area: of the 43 villages, town and covers an area of 80 square kilometers. Jericho
area: of the 7 places and covers an area of 30 square kilometers.
The central station is located in Shu'fath about 2 km from the status of Jerusalem and built in
1956 on an area of 15639 square meters, was officially inaugurated in 17/8/1959.
The sub-stations at the basic constructionwere:
Station Bethlehem / Pincushion
Issuing the Ramallah / transmission
Main offices in Jerusalem
Jericho station
In 18/6/1985 the company took a land leased from the municipality of Jerusalem area 5000 m2
the value of 12500 thousand shekels annually has tried to abolish the municipal lease contract
from one party to that agreement was reached in the end to the rent increase to 15 thousand
dollars a year, the company used a piece of land in question as a repository of the pillars of iron,
wood and electrical cables a result of the steady expansion witnessed by the company.

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1.3 Substations
We have in Ramallah network 14 main substations that feed the city as follow
 Silvana which has two transformers (3311) KV of 15 MVA Capacity.
 Al Terah which has one transformer (3311) KV of 10 MVA Capacity.
 Ramallah north which has two transformers (3311) KV of 15 MVA and 10 MVA
Capacity.
 Biteen west which has one transformer (3311) KV of 15 MVA Capacity.
 Biteen central which has one transformer (336.6) KV of 3 MVA Capacity.
 Ras Al Tahounah which has one transformer (3311) KV of 10 MVA Capacity.
 Dar Al Moalmeen which has two transformers (3311) KV of 10 MVA and 15 MVA
Capacity.
 Singel which has one transformer (3311) KV of 10 MVA Capacity.
 Deer Jreer which has one transformer (3311) KV of 5 MVA Capacity.
 Silwad which has one transformer (3311) KV of 3 MVA Capacity.
 Al-Rehan which has one transformer (3311) KV of 5 MVA Capacity.
 Kharbatha which has one transformer (3311) KV of 15 MVA Capacity.
 Nabi-Saleh which has one transformer (3311) KV of 15 MVA Capacity.
 Tri-fitness which has two transformers (3311) KV of 10 MVA and 15 MVA Capacity.
There is transmission lines between the main buses is 33 KV, the network is ring configuration,
all Ramallah loads take power from these buses
These buses feed from 7 feeders as follows:
 Pereg has 20 MVA Capacity.
 Ofar has 20 MVA Capacity.
 Ramallah 20 MVA Capacity.
 Rama1 20 MVA Capacitiy.
 Al Ram 20 MVA Capacity.
 Nabi-Saleh 10 MVA Capacity.
 Qalandia 20 MVA Capacity.
These feeders come from the main connections point with the Israelis electric company.

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1.4 Elements of the network
I. Transformers
 The high voltage transformers on the main substations (33KV/11KV)
MVA # of transformers Total capacity(MVA)
15 8 120
10 6 60
5 1 5
3(33KV/6.6KV) 2 6
Total 18 191
TABLE -1.1- (Ratings of power transformers)
All transformers has tap changer with load= ±10%
II. Transmissionlines
 33KV transmission
Overhead transmission lines ACSR (3X120+1X50) mm
Underground CABLE COPPER XLPE single core 150mm
 11KV transmission
Overhead transmission lines ACSR (3X50+1X50) mm
Underground CABLE COPPER XLPE (3X95 +1X50) mm

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1.5 Load categories
The nature of the loads in Ramallah city varies between residential, commercial, industry, water
pumps and light streets, and the following table shows each category and it’s percentage from the
total consumption.
Table1.2 Load category and its percentage consumption from total consumption
1.6 Power-system protection
is a branch of electrical power engineering that deals with the protection of electrical power
systems from faults through the isolation of faulted parts from the rest of the electrical network.
The objective of a protection scheme is to keep the power system stable by isolating only the
components that are under fault, whilst leaving as much of the network as possible still in
operation. Thus, protection schemes must apply a very pragmatic and pessimistic approach to
clearing system faults. For this reason, the technology and philosophies utilized in protection
schemes can often be old and well-established because they must be very reliable.
Components
Protection systems usually comprise five components:
 Current and voltage transformers to step down the high voltages and currents of the
electrical power system to convenient levels for the relays to deal with;
 Protective relays to sense the fault and initiate a trip, or disconnection, order;
 Circuit breakers to open/close the system based on relay commands;
 Batteries to provide power in case of power disconnection in the system.
 Alarm signals and control wires.
Type of sector Percentage
Residential sector (60 – 65)%
Industrial sector (15 – 18) %
Commercial sector (10 – 12)%
Water pumping 5%
Street lighting (3 – 4)%

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For parts of a distribution system, fuses are capable of both sensing and disconnecting
faults.
Failures may occur in each part, such as insulation failure, fallen or broken transmission
lines, incorrect operation of circuit breakers, short circuits and open circuits. Protection
devices are installed with the aims of protection of assets, and ensure continued supply of
energy.
Switchgear is a combination of electrical disconnects switches, fuses or circuit breakers used
to control, protect and isolate electrical equipment. Switches are safe to open under normal
load current, while protective devices are safe to open under fault current.
Protective device
A protective relay for distribution networks
 Protective relays control the tripping of the circuit breakers surrounding the faulted part
of the network
 Automatic operation, such as auto-reclosing or system restart
 Monitoring equipment which collects data on the system for post event analysis
While the operating quality of these devices, and especially of protective relays, is always
critical, different strategies are considered for protecting the different parts of the system. Very
important equipment may have completely redundant and independent protective systems, while
a minor branch distribution line may have very simple low-cost protection.
There are three parts of protective devices:
 Instrument transformer: current or potential (CT or VT)
 Relay
 Circuit breaker
Advantages of protected devices with these three basic components include safety, economy, and
accuracy.
 Safety: Instrument transformers create electrical isolation from the power system,
and thus establishing a safer environment for personnel working with the relays.
 Economy: Relays are able to be simpler, smaller, and cheaper given lower-level
relay inputs.
 Accuracy: Power system voltages and currents are accurately reproduced by
instrument transformers over large operating ranges.

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Classificationofthe relay
* Principle of operation
* Nature of the relay
* Tome of operation
* Kind of contacts
Types of protection
Generator sets – In a power plant, the protective relays are intended to prevent damage to
alternators or to the transformers in case of abnormal conditions of operation, due to internal
failures, as well as insulating failures or regulation malfunctions. Such failures are unusual, so
the protective relays have to operate very rarely. If a protective relay fails to detect a fault, the
resulting damage to the alternator or to the transformer:
 Damage to the alternator or to the transformer might require costly equipment repairs or
replacement, as well as income loss from the inability to produce and sell energy.
 High-voltage transmission network – Protection on the transmission and distribution
serves two functions: Protection of plant and protection of the public (including
employees). At a basic level, protection looks to disconnect equipment which experience
an overload or a short to earth. Some items in substations such as transformers might
require additional protection based on temperature or gas pressure, among others.
 Overload and back-up for distance (overcurrent) – Overload protection requires a current
transformer which simply measures the current in a circuit. There are two types of
overload protection: instantaneous overcurrent and time overcurrent (TOC).
Instantaneous overcurrent requires that the current exceeds a predetermined level for the
circuit breaker to operate. TOC protection operates based on a current vs time curve.
Based on this curve if the measured current exceeds a given level for the preset amount of
time, the circuit breaker or fuse will operate.
 Earth fault ("ground fault" in the United States) – Earth fault protection again requires
current transformers and senses an imbalance in a three-phase circuit. Normally the three
phase currents are in balance, i.e. roughly equal in magnitude. If one or two phases
become connected to earth via a low impedance path, their magnitudes will increase
dramatically, as will current imbalance. If this imbalance exceeds a pre-determined value,
a circuit breaker should operate. Restricted earth fault protection is a type of earth fault
protection which looks for earth fault between two sets current transformers[4] (hence
restricted to that zone).

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 Distance (impedance relay)– Distance protection detects both voltage and current. A fault
on a circuit will generally create a sag in the voltage level. If the ratio of voltage to
current measured at the relay terminals, which equates to impedance, lands within a
predetermined level the circuit breaker will operate. This is useful for reasonable length
lines, lines longer than 10 miles, because its operating characteristics are based on the
line characteristics
 Back-up – The objective of protection is to remove only the affected portion of plant and
nothing else. A circuit breaker or protection relay may fail to operate. In important
systems, a failure of primary protection will usually result in the operation of back-up
protection. Remote back-up protection will generally remove both the affected and
unaffected items of plant to clear the fault. Local back-up protection will remove the
affected items of the plant to clear the fault.
 Low-voltage networks – The low-voltage network generally relies upon fuses or low-
voltage circuit breakers to remove both overload and earth faults.
Performance measures
Protection engineers define dependability as the tendency of the protection system to operate
correctly for in-zone faults. They define security as the tendency not to operate for out-of-zone
faults. Both dependability and security are reliability issues. Fault tree analysis is one tool with
which a protection engineer can compare the relative reliability of proposed protection schemes.
Quantifying protection reliability is important for making the best decisions on improving a
protection system, managing dependability versus security tradeoffs, and getting the best results
for the least money. A quantitative understanding is essential in the competitive utility industry.
[8][9]
Performance and design criteria for system-protection devices include reliability, selectivity,
speed, cost, and simplicity.[10]
 Reliability: Devices must function consistently when fault conditions occur, regardless of
possibly being idle for months or years. Without this reliability, systems may result in
high costly damages.
 Selectivity: Devices must avoid unwarranted, false trips.
 Speed: Devices must function quickly to reduce equipment damage and fault duration,
with only very precise intentional time delays.
 Economy: Devices must provide maximum protection at minimum cost.
 Simplicity: Devices must minimize protection circuitry and equipment.
Our project aims to make Ramallah’s network more reliable by increasing the power factor and
the voltage levels to reduce the losses and the penalty which comes from the low power factor.

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1.7 Constrains
In our project we faced many constrains such as:
 No one line diagram for the net work so we had to built the net work by our self using the
Excel which we were given.
 The cost of the capacitor bank we were not be capable to be a wear.
 A lot of time and hard work were needed.
 Geographical problems.
 Political problems.
 The company use IEC standard.
 We faced a lot of problem with the cables.
1.8 Standard/ Code:
In this project we used the International Electrotechnical Commission “IEC” just like the
company used it, IEC standards cover a vast range of technologies from power generation,
transmission and distribution to home appliances and office equipment, semiconductors, fiber
optics, batteries, solar energy, nanotechnology and marine energy as well as many others. The
IEC also manages three global conformity assessment systems that certify whether equipment,
system or components conform to its International Standards.
IEC standards have numbers in the range 60000–79999 and their titles take a form such as IEC
60417: Graphical symbols for use on equipment. The numbers of older IEC standards were
converted in 1997 by adding 60000, for example IEC 27 became IEC 60027.

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1.9 Methodology
We start our project by building the on line diagram of the network that we analyzed it on its
max. And min. Conditions, after that we improved these conditions using:
 Increasing the swing bus voltage by 10%.
 Increasing the tern’s ratio of the transformer by 5%.
 Adding capacitor banks.
To increase the power factor and the voltage levels to reduce the power losses.
In the maximum load stage we fill the network component as like in the real-time then we
analyzed the network -by using the power programs- the voltages in the buses and the losses of
the active and reactive power in the network and the power factor in each bus.
In the minimum load stage, the load will decrease by 65% from the maximum load so the
voltage will decrease from the nominal value in the small ratio we can improve it by increasing
the swing bus voltage in some cases we need a capacitor bank.
Then we mad protection system for a few elements to increase the reliability of the network.
Then we made an economical study in order to decide whether our decision well fit or not.

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2.1 Analysis Maximum Condition
After first run on ETAP, the network condition was as the following figures and tables.
Singel, Deer-Jreer, Silwad and Biteen substations.
` Fig 2.1

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Tahounah, Ramallah North and Terah substations.
Fig 2.2
Silvana, Ramallah City and Kharbatha substations.
Fig 2.3

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Al-Moalmeen, Qalandia con. and Tri-fitness substations.
Fig 2.4

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Nabi-Saleh substation.
Fig 2.5
Atarot main connection point.
Fig 2.6

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2.2 Improving Maximum Condition
After improved on ETAP, the network condition was as the following figures and table.
Singel, Deer-Jreer, Silwad and Biteen substations.
Fig 2.7

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Tahounah, Ramallah North and Terah substation
Fig 2.8
Atarot main connection point.
Fig 2.9

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Silvana, Ramallah City and Kharbatha substations.
Fig 2.10

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Al-Moalmeen, Qalandia con. and Tri-fitness substations.
Fig 2.11
Nabi-Saleh substation.
Fig 2.12

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2.3 Maximum Condition Results
Table 2.1: The voltages before and after improved of Maximum condition.
Bus Name Before After
Rated Voltage (KV) Voltage (KV)
Al-Moalmeen 33.0 31.42 33.18
Al-Ram 33.0 32.61 34.22
Al-Rehan 33.0 30.85 32.72
Biteen 6.6 6.60 6.51 6.90
Biteen central 33.0 32.76 34.45
Biteen west 33.0 31.90 33.66
Bus5 11.0 10.32 11.03
Bus6 33.0 32.54 34.19
DeerJreer 33.0 34.29 35.49
Grand 11 11.0 10.53 11.18
Jreer 11 11.0 11.22 11.75
Kharbatha 11 11.0 10.51 11.21
Kharbatha 33.0 32.34 34.08
Rehan 11 11.0 10.19 10.89
Moalmeen 11 11.0 10.24 10.96
Nabi-Saleh 11.0 10.73 11.39
Qalandia 33.0 32.89 34.56
Ramallah 11 11.0 10.24 11.00
Ramallah City 33.0 32.44 34.10
Ramallah North 33.0 31.50 33.33
Singel 11 11.0 11.56 11.80
Silwad 11 11.0 11.14 11.69
Silvana 33.0 32.44 34.08
Silvana 11 11.0 10.53 11.19
Silwad 33.0 33.70 35.08
single 33.0 35.41 35.83
Tahona11 11.0 10.25 11.08
Al-Tahounah 33.0 31.55 33.46
Terah11 11.0 10.45 11.06
Al-Terah 33.0 31.99 33.64
Tri-fitness 33.0 30.77 32.59
Tri-load 11.0 9.98 10.73

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Here are a few numbers of power factors that we have chosen and for more information you can
see at the end of reports.
Table 2.2: The power factor state before and after improving.
Bus name Before P.F (lagging) % After P.F (lagging)%
Silwad 89.2 94.8
Biteen west 88.0 93.6
Singel 87.4 97.5
Jreer 83.7 94.1
moalmeen 83.4 94.7
Ramallah city 89.4 93.0
Nabi-Saleh 88.1 92.1
Ramallah North 89.8 96.0
Tahounah 87.7 93.8
Tri-fitness 89.8 95.7
Terah 88.5 92.3
Qalandia 87.7 94.0
Silvana 88.9 91.9
AL-Ram 88.7 94.5
Table 2.3: The total demand and losses for maximum cond. before and after imp.
Before After
Total demand (MW) 113.9 121.91
Total demand (MVAr) 62.01 45.76
Total demand (MVA) 129.68 130.21
P.F % 87.8 lagging 93.6 lagging
Apparent losses (MW) 4.808 3.55

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3.1 Analysis Minimum condition
After first run on ETAP, the network condition was as the following figures and tables.
Singel, Deer-Jreer, Silwad and Biteen substations.
Fig 3.1

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Tahounah, Ramallah North and Terah substations.
Fig 3.2
Silvana, Ramallah City, AL-Ram con. and Kharbatha substations.
Fig 3.3

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Al-Moalmeen, Qalandia con. and Tri-fitness substations.
Fig 3.4
Nabi-Saleh substation.
Fig 3.5

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Atarot main connection point.
Fig 3.6

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3.2 Improving Minimum Condition
After improved on ETAP, the network condition was as the following figures and table.
Singel, Deer-Jreer, Silwad and Biteen substations.
Fig 3.7

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Tahounah, Ramallah North and Terah substation
Fig 3.8
Atarot main connection point.
fig 3.9

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Silvana, Ramallah City, AL-Ram con. and Kharbatha substations.
Fig 3.10

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Al-Moalmeen, Qalandia con. and Tri-fitness substations.
Fig 3.11
Nabi-Saleh substation.
Fig 3.12

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3.3 Minimum Condition Results
Table 3.1: The voltages before and after improved for minimum condition
Bus Name Before After
Rated Voltage (KV) Voltage (KV)
Al-Moalmeen 33.0 32.06 33.72
Al-Ram 33.0 32.77 34.42
Al-Rehan 33.0 31.68 33.29
Biteen 6.6 6.6 6.59 6.88
Biteen central 33.0 33.0 34.34
Biteen west 33.0 32.45 33.87
Bus5 11.0 10.6 11.21
Bus6 33.0 32.87 34.30
Deer Jreer 33.0 35.06 34.89
Grand 11 11.0 10.72 11.32
Jreer 11 11.0 11.54 11.62
Kharbatha 11 11.0 10.73 11.32
Kharbatha 33.0 32.74 34.17
Rehan 11 11.0 10.5 11.11
Moalmeen 11 11.0 10.56 11.17
Nabi-Saleh 11.0 10.82 11.47
Qalandia 33.0 32.93 34.58
Ramallah 11 11.0 10.53 11.42
Ramallah City 33.0 32.72 34.25
Ramallah North 33.0 32.11 33.69
Singel 11 11.0 12.01 11.59
Silwad 11 11.0 11.38 11.60
Silvana 33.0 32.72 34.24
Silvana 11 11.0 10.72 11.32
Silwad 33.0 34.32 34.74
single 33.0 36.52 35.17
Tahona11 11.0 10.54 11.18
Al-Tahounah 33.0 32.14 33.79
Terah11 11.0 10.67 11.22
Al-Terah 33.0 32.42 33.85
Tri-fitness 33.0 31.49 33.10
Tri-load 11.0 10.31 10.93

37. Page | 37
Here are a few numbers of power factors that we have chosen and for more information you can
see at the end of reports
Table 3.2: The power factor state before and after improving.
Bus name Before (lagging) After(lagging)
Silwad 88.6 94.2
Biteen west 88.5 94.2
Singel 87.4 95.6
Jreer 84.1 94.4
moalmeen 74.3 91.5
Ramallah city 89.1 93.4
Nabi-Saleh 88.7 94.1
Ramallah North 89.8 94.8
Tahounah 89.0 95.2
Tri-fitness 89.8 94.1
Terah 89.0 92.4
Qalandia 88.7 92.4
Silvana 91.0 92.3
ram 90.0 93.0
Table 3.3: The total demand and losses for minimum cond. before and after imp.
Before After
Total demand (MW) 77.0 82.37
Total demand (MVAr) 40.5 31.76
Total demand (MVA) 86.98 88.28
P.F % 88.5 lagging 93.3 lagging
Apparent losses (MW) 2.63 1.72

38. Page | 38
4. Powers-System Protection
Power transformer protection
The faults that might happen on the transformer:
 Short circuit on transformer windings
 Phase to phase
 Over load
Protection that might be used in the transformer:
 Differential protection to protect the transformer from phase to phase fault.
 Bucholz protection for inter turn faults.
 Thermal protection for over load.
 Erath fault protection from phase to ground faults.
 Short circuit to protect at internal faults.
For the power transformer we made the differential protection on three transformers the equation
were used to calculate the value of the circuit breakers
IC.B>= K*I max load
VC.B>=System
I breaking>=K*IS.C
Note:
K=factor of safety
Isc=sort circuit current.

39. Page | 39
The first transformer is at al Nabi-Saleh connection point the transformer changes from
(33-11)KV
Fig 4.1
Circuit breaker calculation:
Fault (1) before the transformer
Imax=123 A
Sbase= 7.5Mva
G imp= .1 pu
Vbase= 33Jv
TL length= 3km
Ztl= .65 ohm/km

40. Page | 40
TR imp= 0.07
Ibase=(Sbase)/(V*sqrt(3))= 131.2 A
Zbase=(V^2)/Sbase= 145.2 ohm
Ztl=(.65*3km)/145.2= .013 pu
Zeq=.1+.013= .113 pu
Isc=1/.113= 8.85 pu
Isc=8.85*131.2= 1160 A
Icb=K*Imax=1.2*123=148 A
Vcb>=Vsys
Ibc=1.2*Isc=1.2*1160=1392 A
Fault(2) after the transformer
Same condition but
Imax= 369 A
Vbase= 11 Kv
Xtr=.07*(sbase/snom)
=0.07*(7.5/15)= 0.035
Zeq=.035+.013=.148 pu
Ibase=Sbase/v*sqrt(3)= 394 A
Isc=1/.148= 6.8 pu
Isc=6.8*394=2662 A
Icb=1.2*Imax=1.2*369= 443 A
Ibc=1.2*Isc=1.2*2662=3195 A

41. Page | 41
Fig 4.2
The transformer after adding the CB

42. Page | 42
The secondcalculationfor al moalmeen transformers
Fig 4.3
Fault (1) before transformer T8& fault (2) before T4

43. Page | 43
Calculation:
Same ways as we did in anabi saleh unit the only difference is that we have double transmission
line.
I base=S/(V*sqrt(3))=927 A
Z base=V^2/S=20.5 ohm
Zeq=.43 pu
I sc=1/.43 =2.23
I sc1=I sc2=2.32*927=2156 A
I cb 1=1.2* Imax=1.2*64=77 A
I cb 2=1.2*96=115 A
I bc 1=1.2*2156=2587 A
I bc 2=1.2*2156= 2587 A
* Fault (3) after T_15 MVA:
Same calculation but different in Z eq.
Z eq = .43+(.07*10/53)= .443
I sc= 1/.443= 2.26
I base= 53/11*sqrt(3)=2782
I sc= 2.26*2782=6288 A
I cb= 1.2* Imax=1.2*288=346
I bc= 1.2* Isc =7545
*Fault after T_10Mva
Z eq = .43+(.07*15/53)= .45
I sc= 1/.45= 2.22

44. Page | 44
I base= 53/11*sqrt(3)=2782
I sc= 2.22*2782=6176 A
I cb= 1.2* Imax=1.2*192= 230 A
I bc= 1.2* Isc =1.2*6176= 7411 A
Fig 4.4

45. Page | 45
5. Economicalstudy
In the economic study do it to know how our design of improving the network is economic
feasible and to know how long the payback period of our design.
The payback period method compares the losses power before improvement with the cost of the
capacitors we used to improve the condition.
The following calculation illustrates an economical study in four conditions after improvement.
Saving in penalties:
- P max=122 MW.
- P min=82 MW
- Losses before improvement=4.8 MW
- Losses after improvement=3.5 MW
- P.F before improvement=87.8
- P.F after improvement=93.6
- P av=( P min+ P max)/2= 102 MW.
- Total energy per year=P av*8760= 893520 MWH.
- Total cost per year=Total energy*cost(NIS/KWH)
= 893520*0.5
= 446760000 NIS/year.
- Saving in penalties of P.F= 0.01*(.93-0.87.8)*Total cost of energy
= 26805.6 NIS/year.
Saving in losses:
-Average losses before improvement =3.72MW.
- Energy of the losses before improvement=3.72*8760=32543.4 MWH.

46. Page | 46
- Cost of losses before improvement= 32543400*0.5=16271700 NIS/year.
- Average losses after improvement =2.63MW
- Energy of the losses after improvement=2.63*8760=23083MWH.
- Cost of losses after improvement=32083000*0.5=11541300 NIS/year.
- Saving in losses= cost of losses before –cost of losses after
= 16271700-11541300= 4730400 NIS/year.
Simple Pay Back Period:
- Total fixed capacitor banks using in maximum case=10.45MVaR.
- Cost per KVAR= 3JD=15NIS.
- Total regulated capacitor banks using in maximum case=9MVAR.
- Cost per KVAR= 15JD=75NIS.
- Total cost of capacitor banks= (75*9000) + (10450*15) =831750 NIS.
- Total saving=saving in losses +saving in penalties
= 4757205NIS.
- S.P.B.P=Investment /Saving
= 4757205/831750= 5.7 years.

47. Page | 47
Conclusion:
 In maximum condition we improved the power factor more than 92%, in order of that
the bills are reduced.
 The voltages for all busses are increased above the nominal.
 The power losses are reduced.
 Tow stations are protected by using C.B.
 When the power losses are reduced we saved about 115 M NIS.
 We added C.B fixed and regulated and the payback period is 5.7 years.
Recommendations:
I noticed that the cables are replaced with transmission lines so we misses the chance to get a
leading power factor.
Also we have to raise the power incoming from connection points to enhance the reliability.
At the end I hope the companies we deal with them gets less formally when sharing information
with us, also takes our improved networks in serious, that can happen when we see our project
applied on the ground.
Trust Palestinianengineersbecause weare the future..