Rehabilitation of nablus electrical network by adding a new connection point

1Rehabilitation of the Nablus electrical network
Contents :
List of Figures ……………………….…..………….…………….………………….3
List of Tables ………………………….…..………………………………………….4
Abstract ………………………………………………………………………………5
Chapter 1 : Introduction …………...………………………………………………..6
Chapter 2 : Constraints And Earlier Coursework………………..………………..7
Chapter 3 : Literature Review ………………………….…………………………..9
3.1 Electrical Power System ……………………………………..………..…..9
3.2 Load Flow …………………………………………………….……….…..9
3.3 ETAP Power Station 6 …………………………………………..…….....10
Chapter 4 : Methodology …………………………………………………………..11
4.1 About Our Project …………………………………………....…………..11
4.2 Elements Of Network ………………………………………..….………12
4.2.1 Electrical Supply…………………………………….…………………12
4.2.2 Distribution Transformers………………………………..…………….12
4.2.3 Power Transformers………………………………………………...….14
4.2.4 Over Head Line……………………………………………………...…15
4.2.5 Under Ground Cable……………………………………………….…..16
Chapter 5 : Results And Analysis ………………………………….……………...17
5.1 Load Flow Analysis………………………….…………….……….…….17
5.2 Changing the Voltage Level from 6.6 to 11 kV ………………….......…..18
5.3 The original case …………………………………………………….…..18
5.3.1 The Result Of Load Flow ………………………………………….…..18
5.3.2 Summary of total generation ,loading and demand ……..……….…...20
5.4 The Maximum load Case …………………………..………………………21
5.4.1 Increasing the swing bus voltage …………..…………………….…..22
5.4.1.1 The Result Of Load Flow ……………………….….22
5.4.1.2 Summary of total generation ,loading and demand ….24
5.4.2 Improvement the Maximum case using tap changing ……………….24
5.4.2.1 The Result Of Load Flow …………………………25
5.4.2.2 Summary of total generation ,loading and demand …26

5.5 Maximum Case Improvement …………………..……………………..27
5.6 Add a new connection point ………………………...…………………27
5.6.1 The Result Of Load Flow ………………………………...……29
5.6.2 Comparing the voltages ……………………………………...….30
5.6.3 Summary of total generation ,loading and demand …………….32
Chapter 6 : Discussion …………………………….……………………………….33
6.1 Elements of the new connection point ………………………………..33
6.1.1 Main switch gear ………………………..……………………….33
6.1.2 Measurement in the medium voltage ……………………………37
6.1.3 Supervisory Control & Data Acquisition (SCADA) ……………38
6.2 Power Factor Improvement …………………………………...………40
6.2.1 How to improve the P.F? ………………………………………..41
6.2.2 Capacitor Banks …………………………………...…………….41
6.2.3 Effect of Low Power Factor ………………..……………………41
6.2.4 Power factor correction specification …………….……………..42
6.2.5 Benefits of Improving Power Factor ……………..……………..42
6.2.6 The problem of low power factor ………………….……………42
6.2.7 Summary of total generation ,loading and demand ….………….43
6.2.8 discussion and compare the results …………………..………….43
Chapter 7 : The Economical Study ……..……………………………………………..44
7.1 Saving in penalties ………………………………………………….44
7.2 Saving in losses ………………………….……………………….…45
7.3 Simple Pay Back Period …………………………………………….45
Chapter 8 : Conclusions And Recommendation …………………………...…….47
References …………………………………………………………………………..49

List of Figures :
Figure 1: One Line Diagram Of "Eastern Region" Network ………………...…..5
Figure 2: ETAP Power Station …………………………………….…………...…10
Figure 2: Distribution Transformer in Nablus Network …………..…………….12
Figure 4: PowerTransformer in Nablus Network ………………..………………14
Figure 5: Transmission line ……………………………..…………………..……..15
Figure 6: ACSR Cable ……………………………………………………………..15
Figure 7 : XLPE Cable …………………………………………………………….16
Figure 8 : Some Of Under Voltage Buses (11 &0.4) KV original case……..…..…..19
Figure 9 : Some Of Under Voltage Buses (33 &0.4) KV original case……........…..20
Figure 10: Some Of Under Voltage Buses (11 &0.4) KV increase 10%…….….….23
Figure 11 : Some Of Under Voltage Buses (33 &0.4) KV increase 10 % ……..……23
Figure 12 : Some Of Under Voltage Buses (11 &0.4) KV tap changer ……………26
Figure 13 : One Line Diagram After Adding New Connection Point.…………..28
Figure 14 : Some Of Under Voltage Buses (33 &0.4) KV two con. Point …………31
Figure 15 : Some Of Under Voltage Buses (11 &0.4) KV two con. Point …………31
Figure 16 : The basic connection of C.B control for opening operation ………….34
Figure 17 : The Bus-Bar modules ………………………………………………………..35
Figure 18 : The Isolating Switche …………………………………………………………..36
Figure 19 : The Earth switch ……………………………………………………………….36
Figure 20 : The basic connection of Current Transformers …………………………37
Figure 21 : The basic connection of Potential Transformers …………………………38
Figure 22 : General SCADA SystemLayut ………………………………………………..……40

List of Tables :
Table 1: The number & rating of distribution Transformers …………………..13
Table 2: R &X of distribution Transformers ………………………………….…13
Table 3: The number & rating of power Transformers ……………………..…..14
Table 4: R &X &P ,Q o.c. of power Transformers ……….………………...……14
Table 5: R & X of the ACSR ………………………………………………..……..15
Table 6: R & X of XLPE CU ………………………………………………………16
Table 7 : R & X of XLPE AL …………………………………………..………….16
Table 8: Some Voltage Buses In Original Case.………………………………….18
Table 9: Range Of Voltage In Maximum Case.…………………………………..21
Table 10: Some Voltage Buses In Maximum Case ……………………………….22
Table 11: Some Voltage Buses In Maximum Case after changing the tap……..25
Table 12: Voltage After Adding Con. Point Comparing Original Case ……..…29
Table 13: Voltage After Adding Con. Point Comparing Maximum Case .……..30
Table 14: The penalties of power factor …………………………………………..42

Project’s Abstract:
This project aims to study the performance of Nablus Network and to add a new
connection point in the eastern region of the city of Nablus in the village of "
Huwwara " with maximum capacity up to 20 MW , in cooperation with NEDCO (
Northern Electric Distribution Company) .
Taking into consideration that there are 6 connection points in the electrical
network of the city of Nablus.
A load flow study and analysis for Nablus Electrical Networkusing ETAP software will
be performed to see the effect of adding a new connection point to the network and
to improve the power factor, improve the voltage level and to reduce the electrical
losses in the network , and so reducing the penalties in the total tariff for the
municipality, increasing the reliability of the network.
To do that we will follow the sequence below:
about Nablus electrical network.1 .Collect correct data from NEDCO
2. Run it on software (ETAP) to get the results.
3. Study the network with the new connection point.
Give recommendations and conclusions ..4
Figure 3:One Line Diagram Of "EasternRegion" Network.

Chapter 1:
Introduction
Our project aims to study the performance of Nablus Network and to add a new
Huwwara " with maximum capacity up to 20 MWby using the new version of Etap
program .
Any power system may have problems such as in voltages , currents , low power
factor , and instability , which a power engineer consider and deal with. Our project
is to analyze and make a load flow study using ETAP software for Nablus Network .
The main aim for this project is trying to achieve the optimum performance for "
Eastern Region " Network .
The objectives summarized as follows:
1. Improve the voltage level and reduce the power losses.
2. To get economical benefits and decrease costs on the company and consumers.
3. To increase the network’s reliability and stability.
4. To make the system more protected.
The technical and economical feasibility are considered for adjustments in the
network . We had our practical training in Northern Electricity Distribution Company
"NEDCO", which according to it , they have a lot of problems in a part of Nablus
Network which is: "Eastern Region " Network , the old connection point have
capacity up to 20 MW and the Network consume all the power so we chose our
project to solve this problem by adding new connection point .

Chapter 2 :
Constraints And Earlier Coursework
2.1 Constraints:
The main constraint which was encountered is that we couldn't get exact information
about the lengths of some transmission lines and some loads which will lead to
inaccurate results for the original network of Nablus Network . This constraint was
able to overcome by taking approximate lengths for those transmission lines and
assuming the load factor for those loads to be 70% and other 90 % .
2.2 Earlier Coursework:
Some earlier courses and topics very important for this project especially course
power system analysis 2 that help us to know how the network work and make A
load flow study and analysis Networkusing ETAP software will be performed to see
the effect to the network and to improve the power factor, improve the voltage level
and to reduce the electrical losses in the network , and so reducing the penalties in
the total tariff for the municipality, increasing the reliability of the network.

Some earlier courses and topics that helped and were used in this project effectively:
- Electrical Machines I .
- Electrical Machines II .
- Electrical Machines Laboratory .
- Power Systems Analysis I .
- Power Systems Analysis II .
- Power Systems Laboratory .
- Designand Analysis of Electrical Networks .
- Generation and Conversion Stations .
- Protection and Stability of Power Systems .

Chapter 3:
Literature Review
3.1 Electrical Power System:
Electrical energy is produced through an energy conversion process.The electric power
system is a network of interconnected components which generate electricity by converting
different form of energy,
(Potential energy, kinetic energy, or chemical energy) are the most common forms of energy
converted to electrical energy; and transmit the electrical energy to load centers to be used by
the consumer. The production and transmission of electricity is relatively efficient and
inexpensive, although unlike other forms of energy, electricity is not easily stored and thus
must generally be used as it is being produced.
The electric power system consists of three main subsystems: the generation subsystem, the
transmission subsystem, and the distribution subsystem. Electricity is generated at the
generation station by converting a primary source of energy to electrical energy. The voltage
output of the generators is then stepped-up to appropriate transmission levels using a step-up
transformer. The transmission subsystem then transmits the power close to the load centers.
The voltage is then stepped-down to appropriate levels.
The distribution subsystem then transmit the power close to the consumer where the voltage
is stepped-down to appropriate levels for use by a residential, industrial, or commercial
customer. [5]
3.2 Load Flow:
In power engineering, the power flow study or load-flow study is an important tool
involving numerical analysis applied to a power system. Unlike traditional circuit analysis, 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: reactive, real, and apparent) rather
than voltage and current . It analysis the power system in normal steady-state operation. There
exit a number of software implementations of power flow studies.
In addition to a power flow study itself , sometimes called the base case,many software
implementation perform other type of analysis, such as fault analysis and economic analysis.
In practical, some program use linear programming to find the optimal power flow, the
conditions which give the lowest cost per KW generated.
The great importance of power flow or load-flow studies is in planning the future
expansion of power systems as well as in determining the best operation of existing systems.
The principle information obtained from the power flow study is the magnitude and phase
angle of the voltage at each bus and the realand reactive power flowing in
each line,such as ETAP power station program. [5]

3.3 ETAP power station 6 :
Figure 4: ETAP power station.
ETAP offers a suite of fully integrated Electrical Engineering software solutions including arc
flash, load flow, short circuit, transient stability, relay coordination, cable ampacity, optimal
power flow, and more. Its modular functionality can be customized to fit the needs of any
company, from small to large power systems.
ETAP Real-Time is a fully-integrated suite of software applications that provides intelligent
power monitoring, energy management, system optimization, advanced automation, and real-
time prediction.
ETAP is the most comprehensive enterprise solution for design, simulation, operation,
control, optimization, and automation of generation, transmission, distribution, and industrial
power systems
ETAP Smart Grid offers comprehensive applications enabling electrical utilities to plan,
coordinate, and safely operate their grid. This real-time system has the ability to manage,
control, visualize, optimize, and automate power transmission and distribution networks
So we will use EtAP 6 program in our project to analysis and improve Nablus Network by
adding new connection point .

Chapter 4 :
Methodology
4.1About Our Project :
Our project aims to study the performance of Nablus Network and to add a new
Huwwara " with maximum capacity up to 20 MW by using the new version of Etap
program .
The network consists of:
1. Swing bus ( 34 KV – 20 MW )
2. ( 277 ) bus in this network .
3. ( 107 ) load buses ( residential, industrial, commercial).
4. One substation with ( 2 ) power transformer ( 33 KV / 6.6 KV ) .
5. ( 108 ) Distribution transformer .
Methods of improvement of the operating conditionin electrical network:
1. Swing bus control.
2. Change the taps of the transformer.
3. Installation of capacitor banks (reactive power compensation).
For this project, the following steps was taken:
Step 1: Gathering and collection of data from NEDCO which consists of:
a) Lengths and impedances of the transmission lines.
b) Approximate loads on the transformers, which a load factor of ( 70% -
90%)
Step 2: Drawing and plotting the one-line diagram of the network using the ETAP
software.
Step 3: Analyzing and studying the network in its approximated load condition.

4.2 Elements Of Network:
Nablus Network has 6 connection point one of them in " Eastern Region " this section study the
elements of the network such as transformers, over headlines and underground cables.
4.2.1 Electrical Supply:
Nablus Electrical is provided by Israel electrical company (IEC) through an over head transmission
line of 33 kV. The max demand is reached (20MW).
Themain supply for electrical distribution network in the Ara'el. And the voltage of the existing
distribution networks are 33 kv only.IEC supplies electricity to the electrified communities by 33 KV
by overhead lines. Electricity is purchased from IEC and then distributed to the consumers. Palestine
has not yet a unified power system , the existing network is local low voltage distributions networks
connected to Israeli electrical corporation (IEC) , where around 95 % of consumed energy were and
still supplied by the IEC .
4.2.2 DistributionTransformers:
Nablus network consists of 108 distribution transformers .
Figure 5: Distribution Transformer in Nablus Network .

The followingTable 1-2showsthe numberof eachthemand the rated KVA.
Number of
Transformers
Transformer
Ratings (KVA)
2 2000
1 1600
3 1000
43 630
34 400
16 250
8 160
1 100
108 Total
Table 3: The number & rating of distribution Transformers.
Transformer
Ratings
(KVA)
R
(ohm)
X
(ohm)
Z
(ohm)
2000 0.0006 0.006 0.007
1600 0.0008 0.008 0.009
1000 0.001 0.010 0.010
630 0.002 0.012 0.012
400 0.004 0.015 0.016
250 0.008 0.024 0.025
160 0.01 0.037 0.04
100 0.02 0.044 0.06
Table 4: R &X of distribution Transformers.[3]

4.2.3 Power Transformers:
Nablus network consists of ( 2 ) power transformer (33/ 6.6 KV)
Figure 4: Power Transformer in Nablus Network .
Number of Transformers Transformer Ratings (MVA)
2 10
Table 3: The number & rating of power Transformers.
Transformer
Ratings
(MVA)
R
(ohm)
X
(ohm)
Z
(ohm)
Po.c.
(MW)
Qo.c.
(MVAr)
10 0.8 8.1 0.835 80 60
Table 4: R &X&P, Q o.c. of power Transformers.[2]

4.2.4 Over HeadLine:
- The conductors used in the network are ACSR (Aluminum Conductor Steel Reinforced)
-The resistance and reactance of the ACSR conductor
In the table below: [1,2]
aACSR Cable R (Ohms /Km)
X(Ohms/Km)
120mm2 0.219 0.269
95mm2 0.301 0.322
50mm2 0.543 0.333
Table 5: R & X of the ACSR.[1,2]
Figure 5: Transmission line .
Figure 6: ACSR Cable.

4.2.5 Under Ground Cable :
-The underground cable used in the network are XLPE Cu ,XLPE Al .
-The resistance and reactance of XLPE in below tables :
Figure 7 :XLPE Cable.
XLPE CU R(Ohms/Km)
R(Ohms/Km)
X(Ohms/Km)
X(Ohms/Km)240mm2 0.754 0.109
120mm2 0.196 0.117
95mm2 0.41 0.121
50mm2 0.387 0.138
Table 6: R & X of XLPE CU.[1,2]
Table 7 : R & X of XLPE AL.[1,2]
XLPE AL R(Ohms/Km) X(Ohms/Km)
95mm2 0.32 0.542

Chapter 5 :
Results And Analysis
5.1 Load Flow Analysis:
In this semester the following steps are to be done:
Step 1: Collection of data for the new connection point which consists of :
 Finding the new location to add a new connection point .
 Preparing data for the transmission lines that will connect with the new
connection point and determine their specifications .
 choose specifications for Switchgear, Transformers and Circuit Breakers.
Step 2: Plotting the one line diagram in ETAP program for new condition by adding
the new supply bus .
Step 3: Analyzing and studying the network in its approximated load condition and
after changing the voltage level to 11 kV instead of 6.6 kV at the low voltage side of
transformers.
Step 4: Analysis and improvement of the original network in maximum load case
then comparing this case with the case of adding a new connection point .

5.2 Changing the Voltage Level from 6.6 to 11 kV:
In this case, each 6.6 kV low voltage side will be exchanged by 11 kV. The same
transformers are used because the transformers which are available have two
windings on the low voltage side of 6.6 kV and 11 kV. Distribution transformers
of 33/11 and 33/6.6 kV will not be changed too . So, no new transformers are
needed .
5.3 The original case :
In order to begin a study, the first step is to formulate the single line diagram of the
system. Equipment data is then collected in order to construct the system correctly.
In this case, the network has been analyzed under two ranges of voltages which are
(33kV, 11kV ) and simulating this network using E-tap program when this network is
loaded with maximum load case.
5.3.1 The Results Of Load Flow :
The following table shows the under voltages on some buses in original case :
Bus Rated Voltage (kV) Operating Voltage (kV)
Bus1 34 34.000
Bus2 33 33.532
Bus15 33 33.383
Bus20 33 33.043
Bus29 33 32.571
Bus52 33 31.899
Bus57 33 31.634
Bus65 33 31.503
Bus73 33 31.148
Bus99 33 31.016
Bus104 33 31.00
Bus54 33 31.771
Bus55 11 10.427
Bus110 11 10.355
Bus125 11 10.277
Bus129 11 10.319
Bus133 11 10.302
Bus143 11 10.167
Bus153 11 10.356
Bus165 11 10.263
Bus191 11 10.331
Bus200 11 10.280

Bus228 11 10.227
Bus269 11 10.087
Bus239 11 10.31
Bus252 11 10.175
Bus122 0.4 0.365
Bus144 0.4 0.360
Bus172 0.4 0.365
Bus182 0.4 0.362
Bus217 0.4 0.364
Bus227 0.4 0.356
Bus254 0.4 0.357
Bus268 0.4 0.384
Bus105 0.4 0.366
Table 8: Some Voltage Buses In Original Case.
Figure 8: Some Of Under Voltage Buses (11 & 0.4) kV.

Figure 9: Some Of Under Voltage Buses (33 &0.4) kV.
5.3.2 Summary of total generation ,loading and demand :

There are many problems in the network that appear after analysis:
From the above results , there are many problems in the network .The P.F of
the swing bus = 82.24 Lagging , which causes high penalities and losses . So,
we try to increase the power factor of the busses and the voltage of the buses
which is not included in the acceptable range .
And the summary above shows the real and reactive power flow, and the power
factor in the network . Therefore ,we note that when we change the Voltage
Level from 6.6 to 11 kV the losses for network decrease from 8.9% to 7.8%
.
5.4 The Maximum loadCase :
Most of the buses are below the criteria for voltages in the case of Max load
operation.
This criteria show that the voltage should be within this range :
1.05 V nominal<V<1.1 V nominal
nominalV Range of V Max. Load operation
33 KV 34.65< V < 36.3 KV
11 KV 11.55 < V < 12.1 KV
0.4 KV 0.42<V<0.44 KV
Table 9: Range Of Voltage In Maximum Case.
Our goal is to improve the voltages of these criteria by using the following three
steps of improving the electrical network :
1. Increasing the nominal voltage of swing bus by ratio 10%.
2. Increasing the turn’s ratio of Tap change under load to 5% of its original ratio.
3. Inserting capacitors in the nodes which suffer from depression of voltage in order
to produce Q and increase V.
These three steps must be done respectively because raising the swing bus voltage and
changing the turn ratio do not cost money while adding capacitors cost a lot of money.
So, we firstly start with the free ways to improve the network.

5.4.1 Increasing the swing bus voltage:
To increase the voltage on the swing bus up to 10% from the original
voltage (33 kV) , the new value of the swing bus voltage equals (36.3 kV).
After increasing the nominal voltage , the voltage at the buses increases as being shown in
the following table :
5.4.1.1The Results Of Load Flow:
The following table shows the under voltages on some buses in original case :
Bus Rated Voltage (KV) Operating Voltage (KV)
Bus1 36.3 36.300
Bus2 33 35.856
Bus15 33 35.716
Bus20 33 35.395
Bus29 33 34.950
Bus52 33 34.318
Bus57 33 34.067
Bus65 33 33.944
Bus73 33 33.608
Bus99 33 33.484
Bus104 33 33.477
Bus54 33 34.197
Bus55 11 11.329
Bus110 11 11.262
Bus125 11 11.188
Bus129 11 11.229
Bus133 11 11.212
Bus143 11 11.084
Bus153 11 11.262
Bus165 11 11.176
Bus191 11 11.239
Bus200 11 11.192
Bus228 11 11.141
Bus269 11 11.018
Bus239 11 11.224
Bus252 11 11.097
Bus122 0.4 0.399
Bus144 0.4 0.394
Bus172 0.4 0.399
Bus182 0.4 0.396
Bus217 0.4 0.397
Bus227 0.4 0.392
Bus254 0.4 0.392
Bus268 0.4 0.413
Bus105 0.4 0.397
Table 10 : Some Voltage Buses In Maximum Load Case.

Figure 10: Some Of Under Voltage Buses (11 &0.4) KV.
Figure 11: Some Of Under Voltage Buses (33 &0.4) KV.

5.4.1.2 Summary of total generation ,loading and demand:
Note :
 As shown in the above results , the voltage of the buses increases.
5.4.2 Improvement the Maximum Load case using tap changing :
In this method the tap changer of the secondary side of the two power
transformers (33-11 kV) is raised to 10% , and we need to increase the turns
ratio of tap change in all distribution transformers by 5% . So, we notice that
the voltage are increased ,and then we have to compare the voltages with
change tap changer with those are not changed .

5.4.2.1 The Results Of Load Flow:
The following table shows the results after changing the tap of the transformers.
Bus Voltage without change
tap changer (kV)
Voltage with change tap
changer (kV)
Bus1 36.300 36.300
Bus2 35.856 35.856
Bus15 35.716 35.716
Bus20 35.395 35.395
Bus29 34.950 34.950
Bus52 34.318 34.318
Bus57 34.067 34.067
Bus65 33.944 33.944
Bus73 33.608 33.608
Bus99 33.484 33.484
Bus104 33.477 33.477
Bus54 34.197 34.197
Bus55 11.329 11.781
Bus110 11.262 11.731
Bus125 11.188 11.640
Bus129 11.229 11.679
Bus133 11.212 11.663
Bus143 11.084 11.536
Bus153 11.262 11.714
Bus165 11.176 11.626
Bus191 11.239 11.691
Bus200 11.192 11.642
Bus228 11.141 11.490
Bus269 11.018 11.502
Bus239 11.224 11.707
Bus252 11.097 11.581
Bus122 0.399 0.436
Bus144 0.394 0.431
Bus172 0.399 0.436
Bus182 0.396 0.433
Bus217 0.397 0.434
Bus227 0.392 0.430
Bus254 0.392 0.430
Bus268 0.413 0.433
Bus105 0.397 0.415
Table 11 : Some Voltage Buses In Maximum Load Case after changing the tap.

5.4.2.2 Summary of total generation ,loading and demand:

Note:
After changing the taps of the transformers, the losses in the network decrease
and the total current decrease too . the losses before were = 2.700 MW, but the
losses after become =2.555MW .
5.5 Maximum Case Improvement:
For more improvements to the maximum Load case, we need to make some
improvement of our system to improve voltages and power factor . Power
factor improvement will be done by adding capacitor banks at the buses at both
transmission and distribution levels and loads. It is more effective to add them
at the low voltage level buses.
The main problem which faces Nablus Electrical Network is that the power
supplied by IEC is not enough for the demand in the city, especially in the
summer season.And because the old connection point has a capacity up to 20
MW which is not sufficient for the network demand because the old
connection point supplies more than one region, such as “Al-Bathan” and the
industrial area .
To solve this problem , we add a new connection point with IEC in the eastern
region of the city of Nablus in the village of " Huwwara " through an over
head transmission line of 33 kV. The max demand is reached approximately to
(20 MW) to cover the total demand .
Electric utilities must meet increasing demand for reliable power distribution
while coping with decreasing tolerance for disruptions and outages. More than
ever, utilities are squeezed to do more with less, and recognize the need to
improve the efficiency of their distribution systems . So for these reasons , we
choose to add a new connection point.
5.6 Add a new connection point :
Now, after we study the performance of Nablus Network we want to add a new
connection point in the eastern region of the city of Nablus at the village of "
Huwwara " with maximum capacity up to 20 MW, and make a load flow study
using ETAP software .

In order to begin adding a new connection point ,we first have to draw the
single line diagram of the system, taking into consideration that the
network has been analyzed under two ranges of voltages which are (33kV
& 11kV ) and simulating this network using E-tap program and then
comparing the voltages before and after adding the new connection point.
Figure 63:One Line Diagram After Adding New Connection Point.

5.6.1 The Results Of Load Flow:
The following table shows the under voltages on some buses after adding new
connection point and comparing the voltages with original case.
Bus Voltage with one
connection point (kV)
Voltage with two
connection point(kV)
Bus1 34.000 34.000
Bus2 33.532 33.818
Bus15 33.383 33.765
Bus20 33.043 33.649
Bus29 32.571 33.497
Bus52 31.899 33.366
Bus57 31.634 33.259
Bus65 31.503 33.134
Bus73 31.148 32.792
Bus99 31.016 32.666
Bus104 31.000 32.658
Bus54 31.771 33.613
Bus55 10.427 11.093
Bus110 10.355 11.024
Bus125 10.277 10.950
Bus129 10.319 10.989
Bus133 10.302 10.973
Bus143 10.167 10.844
Bus153 10.356 11.025
Bus165 10.263 10.936
Bus191 10.331 11.001
Bus200 10.280 10.952
Bus228 10.227 10.792
Bus269 10.087 10.806
Bus239 10.310 11.018
Bus252 10.175 10.889
Bus122 0.365 0.390
Bus144 0.360 0.385
Bus172 0.365 0.390
Bus182 0.362 0.387
Bus217 0.364 0.389
Bus227 0.356 0.383
Bus254 0.357 0.384
Bus268 0.384 0.396
Bus105 0.366 0.387
Table 12 : VoltageAfter Adding New Connection Point&Comparing The Voltages With Original Case.

5.6.2 Comparing the voltages :
The following table shows the under voltages on some buses after adding new
connection point and comparing those voltages with the maximum load case.
Bus Voltage in maximum load
case(kV)
Voltage after adding
connection point(kV)
Bus1 36.300 34.000
Bus2 35.856 33.818
Bus15 35.716 33.765
Bus20 35.395 33.649
Bus29 34.950 33.497
Bus52 34.318 33.366
Bus57 34.067 33.259
Bus65 33.944 33.134
Bus73 33.608 32.792
Bus99 33.484 32.666
Bus104 33.477 32.658
Bus54 34.197 33.613
Bus55 11.781 11.093
Bus110 11.731 11.024
Bus125 11.640 10.950
Bus129 11.679 10.989
Bus133 11.663 10.973
Bus143 11.536 10.844
Bus153 11.714 11.025
Bus165 11.626 10.936
Bus191 11.691 11.001
Bus200 11.642 10.952
Bus228 11.490 10.792
Bus269 11.502 10.806
Bus239 11.707 11.018
Bus252 11.581 10.889
Bus122 0.436 0.390
Bus144 0.431 0.385
Bus172 0.436 0.390
Bus182 0.433 0.387
Bus217 0.434 0.389
Bus227 0.430 0.383
Bus254 0.430 0.384
Bus268 0.433 0.396
Bus105 0.415 0.387
Table 13 : Voltage After Adding New Connection Point &Comparing The Voltages With Maximum load
Case.

Figure 15: Some Of Under Voltage Buses (11&0.4) kV.

5.6.3 Summary of total generation ,loading and demand:
Note:
As shown in the previous tables , when adding a new connection point ,
the drop voltage was clearly decreased and improved . The power factor
of the swing bus equals 83.39 lagging , which is low and causes a lot of
penalties on both the company and consumers , which causes high losses
too . So, we have to try to increase the power factor of the busses .
The summary above shows the real and reactive power flow, Therefore ,we
note that when adding a new connection point the losses for network
decrease from 8.9% to 3.4% .

Chapter 6 :
Discussion
6.1 Elements of the new connection point :
6.1.1 Main switch gear :
The connection point contains many elements , switchgear is the
combination of electrical disconnect switches , fuses or circuit breakers used
to control and protect electrical equipment . Switchgear is used both to de-
energize equipment to allow work to be done and to clear faults downstream.
This type of equipment is directly linked to the reliability of the electricity
supply.
switchgears in substations are located on both the high and low voltage sides
of large power transformers. The switchgear on the low voltage side of the
transformers may be located in a building, with medium voltage circuit
breakers for distribution circuits, along with metering , control, and protection
equipment. in our connection point a transformer and switchgear line up may
be combined in one location .[6]
Switchgear contain of :
1- CIRCUIT BREAKER :
During the normal operating condition the Circuit Breaker can be opened or
closed by a station operator for the purpose of Switching and maintenance.
During the abnormal or faulty conditions the relays sense the fault and close
the trip circuit of the Circuit Breaker. Thereafter the Circuit Breaker opens.
The Circuit Breaker has two working positions, open and closed, these
correspond to open Circuit Breaker contacts and closed Circuit Breaker
contacts respectively.
The operation of automatic opening and closing the contacts is achieved by
means of the operating mechanism of the Circuit Breaker. As the relay contacts
close, the trip circuit is closedand the operating mechanism of the Circuit
Breaker starts the opening operation. The contacts of the Circuit Breaker open
and an arc is draw between them.
The arc is extinguished at some natural current zero of a.c. wave. The process
of current interruption is completed when the arc is extinguished and the
current reaches final zero value. The fault is said to be cleared.

The process of current interruption is completed when the arc is extinguished
and the current reaches final zero value. The fault is said to be cleared.[7]
Figure 16: the basic connection of C.B control for opening operation .
How to choose CB :
1- I C.B >= Ksafty * I max load .
2- VC.B >= V system.
3- I breaking capacity >= 1.2 * I S.C
The Specifications ofthe Circuit Breaker that we have used are as
follows:
1- Ur = 36 kV, Up = 170 kV , Ud = 70kV ; 1 min
2- Ir = 1250 A , Ik = 25 kA ; tk = 1sec , Ip = 62.5 kA
2- BUS-BAR :
The Bus-Bar modules are either with single phase or three phase enclosure.
Three phase enclosures are compact and have lesser eddy current losses.
Single phase Bus-Bars are necessary to suit other components having single
phase enclosures. The three Bus-Bars are conveniently staggered by a distance
equal to centre spacing.
The diameter of enclosure depends on rated voltage and internal clearance
requirements.

The main conductors are aluminum or copper tubes. The contact areas are
silver plated. There is a provision of expansion joints which permits axial
elongation at higher temperatures. The tubular conductors are
The dimensions of conductor tubing depend upon the mechanical strength
corresponding to short circuits forces. The size so obtained is generally
adequate for carrying normal current without excessive temperature rise .[7]
Figure 17: The Bus-Bar modules.
3- ISOLATOR SWITCH :
Isolating Switches are normally switched only when not on load but they may
also interrupt the no load current of small Transformers as well as disconnect
short pieces of overhead lines or cables.

Figure 18: The Isolating Switche.
4-EARTH SWITCH :
Earth switch is used to discharge the voltage on the circuit to the earth for
safety , earth switch is mounted on the frame of the isolaters .
Earthing Switch is necessary to earth the conducting parts before maintenance
and also to provide deliberate short-current while testing. There can be three
types of earthing witches in metal-clad Switches manually operated automatic
high speed earthing switch, protective earthing Switch for earthing the
installation.
Earth switch islocatedfor each incomer transmission line and each side of the
bus-bar section .[7]
Figure 19: The Earth switch.

6.1.2 measurement in the medium voltage :
1- Medium-voltage sensors :
for measuring currents and voltages needed for protection and monitoring in
medium voltage power systems.
Electronic Instrument Transformers (Sensors) offer an alternative way of
making the current and voltage measurements. Sensors based on alternative
principles have been introduced as successors to conventional instrument
transformers in order to significantly reduce size, increase safety, and to
provide greater rating standardization and a wider functionality range. These
well known principles can only be fully utilized in combination with versatile
electronic relays.
2- Current Transformers :
Current Transformers comprise air insulated cores mounted inside a cylindrical
enclosure. The central main conductor forms the primary winding a second
cylindrical enclosure,
Between the cores and the conductor, The number and ratings of the cores are
adapted according to customer requirements.
Current Transformers can be installed on either or both sides of the circuit-
breakers and at the ends of outgoing circuits . Current Transformers in our
connection point is ( 400/5 ) A.
figure 20 : the basic connection of Current Transformers .

3- Potential Transformer :
Potential Transformers are induction type and are contained in their
compartment, separated from the other parts of the installation.
The active portion consists of a rectangular core, upon which are placed the
secondary windings and the high voltage winding.
Provision is made for up to two secondary windings for measurement and an
additional open delta winding for earth fault detection . Potential Transformers
in our connection point is ( 33000/110 ) V . [7]
Figure 21 : the basic connection of Potential Transformers .
6.1.3 Supervisory Control & Data Acquisition (SCADA) :
Electric utilities must meet increasing demand for reliable power distribution
while coping with decreasing tolerance for disruptions and outages. More
than ever, utilities are squeezed to do more with less, and recognize the need
to improve the efficiency of their power generation and distribution systems.
Fortunately, many areas of the existing electrical distribution system can be
improved through automation.

Furthermore, by automating the distribution system now, utilities will be
ready to meet the challenges of integrating intermittent supply sources like
solar, wind and other distributed energy resources . Automating electrical
distributions systems by implementing a Supervisory Control And Data
Acquisition (SCADA) system is the one of the most cost-effective solutions for
improving reliability, increasing utilization and cutting costs.
SCADA (Supervisory Control And Data Acquisition) is a system for remote
monitoring and control that operates with coded signals over communication
channels (using typically one communication channel per remote station). The
control 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.
How SCADA Works ?
A SCADA system for a power distribution application is a typically a PC-based
software package . Data is collected from the electrical distribution system,
with most of the data originating at substations.
Depending on its size and complexity, a substation will have a varying number
of controllers and operator interface points. In a typical configuration, a
substation is controlled and monitored in real time by a Programmable Logic
Controller (PLC) and by certain specialized devices such as circuit breakers and
power monitors.
Data from the (PLC) and the devices is then transmitted to a PC-based SCADA
node located at the substation.
One or more PCs are located at various centralized control and monitoring
points. The links between the substation PCs and the central station PCs are
generally Ethernet-based and are implemented via the Internet.

In addition to data collection, SCADA systems typically allow commands to be
issued from central control and monitoring points to substations. These
commands can enable full remote control .[6]
Figure 22 :General SCADA System Layut .
6.2 Power Factor Improvement :
It is important to keep the power factor above 0.92 on the distribution transformer
so as to minimize the electrical losses in the network and do not paying penalties.
Power factor is improved by adding capacitor banks at the buses at both
transmission and distribution levels and loads . And it is more effective to add
them at the low voltage level buses.
The cosine of angle of phase displacement between voltage and current in an
AC circuit is known as Power Factor :

6.2.1 How to improve the P.F?
Where :
( Qc ) : The reactive power to be compensated by the capacitor .
( P ) : The real power of the load.
( QL ) , ( Q’L ) : Inductive reactive output before and after the
installation of the capacitor bank
( A ) , ( A’ ) : apparent power before and after the power factor
correction.
( θ1 ) : The actual power angle
( θ2 ) : The proposed power angle .
6.2.2 Capacitor Banks:
The importance of improvement power factor is by adding shunt capacitor
banks at the buses at both transmission and distribution levels and loads. And
there are more effective to add them in the low level voltages .
6.2.3 Effectof Low PowerFactor :
1. Higher Apparent Current .
2. Higher Losses in the Electrical Distribution network .
3. Low Voltage in the network.

6.2.4 Power factor correctionspecification:
 Don’t insert the capacitor to the generator buses.
 Don’t insert the capacitors to the buses not have a load.
 Don’t allow to the power factor to increases than 1 .
6.2.5 Benefits of Improving Power Factor :
1. Lower Apparent Power.
2. Reduces losses in the transmission line .
3. Improves voltage drop.
4. Avoiding the penalties.
6.2.6 The problem of low power factor :
The low P.F is highly undesirable as it causes an increase in the current
,resulting in additional losses of active power in all the elements of power
system from power station generator down to the utilization devices .In
addition to the losses the low P.F causes penalties.
The following table shows the system of the penalties in our companies:
Power Factor P.F Penalties
P.F≥ 0.92 No Penalties.
0.92>P.F ≥0.8 1% of total bill for each one under 0.92
0.8>P.F≥0.7 1.25%of total bill for each one under 0.92
P.F <0.7 1.5%of total bill for each one under 0.92
Table 14: The penalties of power factor.
Our aim to improve the P.F in order to avoid penalties and to reduce the current
flow in the network which reduce the electrical losses in the network .
We added (7) shunt capacitor banks at the buses at both transmission and
distribution levels and loads with value : ( 400 , 300 , 1000 ) kVAR .

6.2.7 Summary of total generation ,loading and demand:
Note : After adding the capacitor banks the losses inthe network decrease and
the total current decrease
The losses before = 1.168 MW, The losses after =1.010 MW
6.2.8discussionandcomparetheresults :
As shown in the previous tables, when changing the voltage level from 6.6 kV
to 11 kV, the drop voltage was clearly decreased / improved.
In the maximum load case : after increasing the tap changer on the secondary
side of two power transformers (33-11 kV) by 10% , and increasing turns ratio
of tap change in all distribution transformers by 5% , the drop voltage was
further decreased / improved , and the voltages became in range ( between
100% and 110% of nominal voltage ) .
Although when changing the voltage level from 6.6 kV to 11 kV, the apparent
losses was decreased. And the power factor was slightly increased
In the maximum load case : when the tap changer was increased, the apparent
losses were decreased even further . And the power factor was clearly and
highly improved .
The sought power factor was 92.09% which it was achieved, since a power
factor was lower than that, it would lead to penalties on both the Northern
Electricity Distribution Company "NEDCO" and consumers .

Chapter 7:
The Economical Study
The improvement of any project must succeed economically .So , in this
chapter , we will study another face of the project which is very important to
study .
After we finished all the cases and improvements of the load flow , in this
project it is important to study the economical calculation to find if our work is
suitable or not . To find this we will use the payback period method .
7.1 Saving in penalties :
- Pmax = 33.626 MW.
- Pmin = 15.45 MW.
- Losses before improvement = 1.168MW.
- Losses after improvement = 1.010MW.
- P.F before improvement = 0.8339
- P.F after improvement = 0.9209
- Pav = L.F * Pmax = 0.75 * 33.626 = 25.21 MW
- L.F = 0.75
- Total energy per year = Pav * 8760= 220839.6 MWH.
- Total cost per year = Total energy * cost (NIS/KWH)
= 220839.6 *1000* 0.6
=132503760 NIS/year.
- Saving in penalties of P.F= 0.01 *(0.9209-0.8339) * Total cost of energy
= 115278.27 NIS/year.

7.2 Saving in losses :
- Average losses before improvement = 0.75 * 2.7 MW = 2.025 MW.
- Energy of the losses before improvement = 2.025 * 8760 = 17739 MWH.
- Cost of losses before improvement = Total energy losses * cost (NIS/KWH)
= 17739 *1000* 0.6
= 1064340 NIS/year.
- Average losses after improvement =0.75 * 1.010 = 0.7575 MW.
- Energy of the losses after improvement = 0.7575 * 8760 = 6635.7 MWH.
- Cost of losses after improvement = Total energy losses * cost (NIS/KWH)
= 6635.7*1000* 0.6
= 398142 NIS/year.
- Saving in losses= cost of losses before –cost of losses after
= 1064340 – 398142
= 666198 NIS/year.
7.3 Simple Pay Back Period :
- Total fixed capacitor banks using in maximum case
= 7.3 MVAR.
- Cost of fixed capacitor = 5000$ / MVAR = 18000 NIS / MVAR .
- Total cost of capacitor banks = 7.3 * 18000 = 131400 NIS.
- The cost of under ground cable XLPE (1*240 mm2) = 100 NIS / 1 meter
- Total cost = 100 * 8000 = 800000 NIS .
- The cost of Infrastructure (such as: excavations, power source, accessories)
= 100 NIS/1meter
- Total cost = 100 * 8000 = 800000 NIS .
- The cost of ( Links , wages of workers , equipment , Towers , installation
cost and maintenance ) = 300000 NIS .

- The cost of ( Internal equipment, construction, measurement device ,
SCADA system)
= 500000 NIS .
 Total capital cost = 131400 + 800000 + 800000 + 300000 + 500000
= 2531400NIS
 Total saving = saving in losses +saving in penalties
= 666198 + 115278.27
= 781476.27 NIS
 S.P.B.P = Investment /Saving
= 2531400 /781476.27 = 3.23 years
The time needed to recover the cost for the project is about 3 years .

Chapter 8 :
Conclusions And Recommendation
After the analysis and adding a new connection point of "East Reagion"
network by using the ETAP program , drop voltage was decreased ,
apparent losses was reduced too , The losses become 3.4% in the
network. But in fact, according to "NEDCO", the losses is much higher
than that, and this is because of problems in cables and lines, or from the
old transformers and thefts that leads to reduced efficiency, which ETAP
program couldn't see due to the loss of these accurate information.
Moreover , the power factor was improved to over 92% which will lead
to a more efficient and stable system and will reduce any penalties paid to
Israel Electrical Company "IEC" on both "NEDCO" Company and
consumers as will, and this is duo to adding a new connection point .
And we concluded that we found the network at full load needing to 34
MW , but the availability of current two connection point is 40 MW . So,
now we in the save side .
The time needed to recover the cost for the project is about 3 year . And
the new network will be feed the new growth of load for the period from
now to 2025 , depending on the annual increase of the loads to cover the
demand in the city, especially in the summer season in the eastern region
of the city of Nablus in the village of " Huwwara " .

We recommend that the next electrical engineering students to work with
such projects, in order to increase their experiences in the power
engineering field, and to use software/programs that simulates such
power systems. We would also recommend that our electrical engineering
department to archive some one-line diagrams from the electrical
distribution companies to give students brief ideas about practical
networks in Palestine.

References :
[1] Northern Electricity Distribution Company "NEDCO"
[2] Справочникпопроектированиюэлектроэнергетическихсистем.
ву : РокотянС.С
[3]Elements of Power System Analysis 4th Ed. by William D.
Stevenson, Jr
[4] Chapman, Stephen (2002). Electric Machinery and Power System
Fundamentals. Boston: McGraw-Hill. Pp
[5] https://en.wikipedia.org/wiki/Power_engineering
[6] RobertW. Smeaton (ed) Switchgear and Control Handbook 3rd
Ed., McGraw Hill, New York 1997
[7] electrical power system and transmission network by : Eng Sayed
Saad Amin , protection systems engineer . Kuwait

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