ANALYSIS OF THE OPERATING ANALYSIS OF THE OPERATING CONDITION OF Qalqilia ELECTRICAL CONDITION OF Qalqilia ELECTRICAL

NETWORKNETWORK

An- Najah National University Faculty of EngineeringElectrical Engineering

Prepared by :Prepared by :

Fadi Bassam Sabri MahmoudFadi Bassam Sabri MahmoudBelal Abed Alkareem Abu Sha’rBelal Abed Alkareem Abu Sha’r

Supervised by : Supervised by :

Dr. MAHER KHAMMASHDr. MAHER KHAMMASH

Introduction to Qalqilia Introduction to Qalqilia NetworkNetwork

Qalqilia electrical distribution network is fed from one connection point by the Israel Electrical Company (IEC) , at 22 KV.

The development of electrical energy purchased from I.E.C.

and growth rate are:

Year

Annual Purcha

sed M.W.H

Growth Rate%

200234727.40

200334727.40

200437273.87.3

200539264.85.34

200644708.013.86

200750830.9613.7

The energy consumed is distributed into different types

Type of loadConsumptio

n

Residential 77.83 %

Commercial 15.61 %

Industrial 2.84 %

Agricultural 2.14 %

Organization 1.58 %

Year∆p %

199515 %

199614 %

199710 %

19989 %

The change of losses in the Qalqilia electrical

distribution network as

shown in the table But in 2008 it decreases to reach about 3 % for max

case.

Elements Of The NetworkElements Of The Network

1. Electrical Supply: One connection point at 22 kV from IEC .The peak power consumption is 11.804 MW 2. Medium voltage lines (Transmission line):There are two type of conductor : a)) The Over Head Lines :The Over Head Lines used in the network are

22KV, ACSR (Aluminum conductor steel reinforced )

With two cross sectional areas ( 50mm2 called Rabbit , 95mm2 called Dog ) .

b)) Under ground cables : Under ground cables used in the network are 22KV , XLPE , 240mm2Cu , 150mm2Cu , 120 mm2AL , 95mm2AL.The resistance / km and reactance / km and max current for all T.L ( Over head lines and under ground cables ) as shown :

Type of T.L

ResistanceOhms/Km

ReactanceOhms/Km

MaxCurrentcapacity

(A)

O.H.LRabbit50 mm2

0.5430.333174

O.H.LDog95 mm2

0.3010.332250

UGC Al 95 mm2

0.410.121250

UGC Cu120 mm2

0.1960.117360

UGC Cu150 mm2

0.1590.114410

3. Distribution Transformers : Number of distribution transformers in Qalqilia network are 49 .All transformer 22KV / 0.4KV Δ-Υ connected , distribution transformers with ratings 630 , 400 ,250 KVA .

Transformer Ratings KVA

No. of Transformers

63018

40029

2502

Problems in Qalqilia networkProblems in Qalqilia network

1. the main T.L coming from the connection point is Rabbit ( 50 mm2 ) did not have the capability to hold the over current resulting in cutting off the supply on the maximum load condition , because total current pass from this line equal 344 A but max capacity current of this line is 174 A.

2 . High drop voltage : this effect on the losses in the network and on the power factor .

Solution: use capacitor banks ( fixed or variable )

3. Bad distribution of the loads on the existing Transformers which cause a poor load factor , because there are some transformers work at max load factor more than 100 % and some transformers work with load factor less than 60 % .

Note that the transformer work with max efficiency when load factor between ( 65-75 ) %.

Solution: change the configuration of some branches

and transformers .

4. One connection point and this lead to make the performance of the network weak .

( no reliability in network )Solution: it is very important to get another

connection point to supply the city .

ETAP Power Station ProgramETAP Power Station Program::

With ETAP’s advanced Load Flow module, you can create and validate your system model with ease and obtain accurate and reliable results. Built-in features like automatic device evaluation, summary alarms / warnings, result analyzer, and intelligent graphics make it the most efficient Load Flow program available today.

ETAP calculates bus voltages, branch power factors, currents, and power flows throughout the electrical system. ETAP allows for swing, voltage regulated, and unregulated power sources with multiple power grids and generator connections. It is capable of performing analysis on both radial and loop systems. ETAP allows you to select from several different methods in order to achieve the best calculation efficiency and accuracy.

IIn our project we do the following stepsn our project we do the following steps::

Step1: collection of data which consist of :Actual loads on transformer and power factorImpedances of transmission lines ( R, X) .

Step2: Plotting the one line diagram in ETAP

Step 3: Analysis and study the maximum and minimum case.

Step 4 : improvement of power factor .

Step 5 : improvement of voltages level by the following scenarios:

1. Rise the swing bus about 105% .2. Using capacitor banks (fixed and regulated) .3. Putting two connection points ( without ring and

with ring ) .4. Changing the main transmission line of the

network .5. Load factor corrections .

Step 6 : economical study. Step 7 : Low Tension analysis.

One Line DiagramOne Line DiagramQalqilia Network

Analysis … Analysis … Results for the max. caseResults for the max. case

Bus

#

Voltage

act

P

MW

Q

MVar

PF

%20.3910.260.1191.850.3850.410.1991.060.3830.260.1291.170.3840.190.0891.480.3860.180.0891.490.3840.200.0991.8

100.3840.230.1190.7110.3850.190.0891.7120.3850.260.1290.9130.3870.360.1790.9140.3840.270.1390.1150.3820.650.2792.4160.3820.180.0890.8170.3800.530.2790.1180.3840.130.0690.7200.3850.160.0791.4210.3850.140.0594.1220.3780.230.1387.9230.3790.290.1292.4240.3860.200.0892.6260.3860.290.1291.7280.3850.130.0593.3

Low Tension Voltages

Bus

#

Voltage

act

P

MW

Q

MVar

PF

%290.3860.130.0494.7300.3840.250.1093.0310.3810.450.1992.2320.3810.340.1493.3340.3820.290.1292.4350.3810.200.0992.1360.3730.330.1593.1370.3720.350.1691.4380.3820.220.1091.3390.3790.340.1393.7400.3790.140.0593.7420.3780.200.1088.9430.3790.190.0990.9450.3810.150.0692.8460.3790.190.0992.8480.3770.240.1092.6490.3790.170.0890.0500.3800.170.0792.2510.3800.220.1189.5520.3810.310.1293.1540.3800.240.0993.4550.3820.360.1592.7560.3790.220.1190.1

Low Tension Voltages

TransformerS RATED

KVA

S ACTUAL

KVA

LF%

140029874.5

2400414103.6

363037559.6

463034454.5

540019849.4

640026165.4

740038095

8400402100.5

925017971.5

1063035856.9

1163035856.6

1240023558.6

1340014536.2

1463022435.6

1540014837.0

Transformer

S RATED

KVA

S ACTUAL

KVA

LF%

1663028745.5

1740019849.4

1863026341.7

1963029546.9

2063037359.3

2140021052.4

2240027167.6

2340038282.0

2440020551.4

2540019849.4

2640024861.9

2740024861.9

2840016942.3

2940021152.7

3040022456.0

Load Factor

Transformer

S RATED

KVA

S ACTUAL

KVA

LF%

3140022455.9

3240013433.5

3340014636.5

3463024238.4

3525014859.2

3640026466.0

3740019548.6

3840022857.0

3963024939.6

4063020833.0

4163036958.6

4240025262.9

4363032050.8

4440021152.7

4540019348.2

4663046774.1

4763027243.2

4863030047.7

4963032651.7

SUMMARY OF TOTAL GENERATION, SUMMARY OF TOTAL GENERATION, LOADING & DEMANDLOADING & DEMAND

MW Mvar MVA % PF ========= ========= ========= ==============

Swing Bus(es): 11.804 5.684 13.101 90.1 Lagging

Total Demand: 11.804 5.684 13.101 90.1 Lagging --------- --------- --------- --------------

Total Static Load: 11.444 4.988

Apparent Losses: 0.360 0.696

% Losses : 3 %

Total Current : 344 A

From the result we can notice thatFrom the result we can notice that

a) P = 11.804 MW and ∆p = 0.360 MWThen ∆p % = 0.36 \ 11.804 = 3 % b) Problem in load factor as shown in the above .d) The power factor at the swing bus is less than

0.92. This causes penalties on the municipality. So we should raise it to 0.92 to avoid penalties .

c) There are problems in network as shown in the Qalqilia network problems , such as the drop voltages in the network which effect on the P.F and on losses .

Raising the swing voltage from 22 kV to Raising the swing voltage from 22 kV to 23.1 kV23.1 kV

We raise voltages o f the swing bus about 105% of its rated voltage

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND

MW Mvar MVA % PF ====== ====== ====== =====

SwingBus(es): 13.127 6.321 14.519 90.1 Lagging

Total Demand: 13.127 6.321 14.519 90.1 Lagging-------------- --------- --------- ---------

Total Static Load: 12.727 5.547Apparent Losses: 0.400 0.773

We note :In this case all voltages above 392 volt

Bus#

Voltage

nom

Voltageact

bus20.400 0.412 Bus50.400 0.406 Bus60.400 0.403 Bus70.400 0.408 Bus80.400 0.405 Bus90.400 0.405 Bus100.400 0.407 Bus110.400 0.405 Bus120.400 0.406 Bus130.400 0.395 Bus140.400 0.405 Bus150.400 0.403 Bus160.400 0.403 Bus170.400 0.401 Bus180.400 0.405 Bus200.400 0.399 Bus210.400 0.405 Bus220.400 0.398 Bus230.400 0.399 Bus240.400 0.407 Bus260.400 0.404 Bus280.400 0.406

Bus#

Voltagenom

Voltage

actBus290.400 0.407 Bus300.400 0.405 Bus310.400 0.402 Bus320.400 0.402 Bus340.400 0.403 Bus350.400 0.402 Bus360.400 0.394 Bus370.400 0.392 Bus380.400 0.403 Bus390.400 0.400 Bus400.400 0.400 Bus420.400 0.399 Bus430.400 0.400 Bus450.400 0.402 Bus460.400 0.400 Bus480.400 0.398 Bus490.400 0.400 Bus500.400 0.400 Bus510.400 0.401 Bus520.400 0.402 Bus540.400 0.400 Bus550.400 0.403 Bus560.400 0.399

We noteWe note

POWER FACTOR IMPROVEMENTPOWER FACTOR IMPROVEMENT

Benefits of Improving Power Factor : 

1. Lower Apparent Power.2. Reduced KWH Losses.3. Improved Voltage leading to enhanced

life of the transformer, cables, switchgear, motors etc., and lower energy cost.

The first step is to raise the power factor to be 92% to avoid penalties .so we’ll add capacitors to meet this value of power factor .

Power factor improvementPF old = 90 %PF desired = 92%We can obtain QC needed by the equation Q c = Q old – Q new =P [tan cos-1(PF old) - tan cos-1(0.92)]We’ll get Qc = 670 kVAr Adding capacitors in delta connection parallel

to the Transformer in secondary side (0.4 kV) .

POWER FACTOR IMPROVEMENT SUMMARY   MW Mvar MVA % PF

======= ====== ========= ====== wing Bus(es): 11.866 5. 000 12.876 92.2 Lagging

-------------- --------- Total Static Load: 11.520 4.327Apparent Losses: 0.3469 0.673

I Swing: 337 A

We notice when we increase power factor the losses in the network decrease

Losses before P.f improvement = 0.360 Mw . Losses after P.f improvement = 0.346 Mw .

Comparison between the original case and the case of power factor improvement

  THE IMPROVEMENT OF VOLTAGE THE IMPROVEMENT OF VOLTAGE

LEVEL LEVEL Maximum load voltage level improvementAdding capacitors (fixed and regulated) in delta connection parallel to

the Transformer in secondary side (0.4 kv)

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND MW Mvar MVA % PF

Swing Bus(es): 12.015 3.174 12.427 96.7 Lagging

Total Demand: 11.804 5.684 13.101 90.1 Lagging

-------------- --------- --------- --------- Total Static Load: 11.691 2.547

Apparent Losses: 0.324 0.627

Total current 326 A.

Comparison between three caseComparison between three case1. the origin case .1. the origin case .2. power factor improvement case . 2. power factor improvement case . 3. voltage level improvement case3. voltage level improvement case. .

Bus#

VoltageOrigin case

VoltageImprove

p.f

VoltageImprove

of voltage level

P.forigin

p.fimprove

p.f

p.fImprove

of voltage level

bus20.3910.3910.39591.891.899.80Bus50.3850.3850.38991.091.097.43Bus60.3830.3830.38991.191.199.45Bus70.3840.3870.39091.491.497.15Bus80.3860.3840.38791.491.497.17Bus90.3840.3840.38791.891.897.04

Bus100.3840.3860.39090.790.799.77Bus110.3850.3840.38791.791.797.23Bus120.3850.3850.38890.990.997.07Bus130.3750.3750.38190.990.997.76Bus140.3840.3840.38790.190.196.46Bus150.3820.3820.38592.492.496.47Bus160.3820.3830.38790.890.898.90

Bus#Voltage

Origin case

VoltageImprove

p.f

VoltageImprove

of voltage

level

P.forigin

p.fimprove

p.f

p.fImprove

of voltage

level

Bus170.3800.3800.38690.190.199.01Bus180.3840.3840.38790.790.798.42Bus200.3850.3790.38391.491.497.70Bus210.3850.3850.38594.194.194.10Bus220.3780.3840.38587.998.898.81Bus230.3790.3850.38692.499.499.42Bus240.3860.3860.38792.692.692.60Bus260.3860.3830.38591.791.795.58Bus280.3850.3860.38693.393.393.30Bus290.3860.3860.38794.794.794.70Bus300.3840.3850.38593.093.093.00Bus310.3810.3820.38492.292.295.83Bus320.3810.3810.38493.392.395.53Bus340.3820.3820.38792.492.499.46Bus350.3810.3810.38692.192.198.85

Bus#Voltage

Origin case

VoltageImprove

p.f

VoltageImprove

of voltage

level

P.forigin

p.fimprove

p.f

p.fImprove

of voltage

level

Bus360.3730.3740.38093.191.398.32

Bus370.3720.3780.37991.498.1098.10

Bus380.3820.3820.38591.391.398.15

Bus390.3790.3840.38493.799.499.40

Bus400.3790.3800.38693.793.799.40

Bus420.3780.3820.38388.997.197.15

Bus430.3790.3820.38390.996.796.65

Bus450.3810.3820.38492.892.896.92

Bus460.3790.3820.38392.896.696.61

Bus480.3770.3810.38192.698.496.82

Bus490.3790.3820.38390.096.496.43

Bus500.3800.3800.38392.292.297.80

Bus510.3800.3830.38489.597.096.99

Bus520.3810.3820.38693.193.199.49

Bus540.3800.3800.38493.493.498.81

Bus550.3820.3820.38492.792.795.66

Bus560.3790.3830.38390.197.397.29

Origin casepower factor improvement

case

voltage level improvement

caseTotal current 344 A337 A326 ATotal

losses0.36 Mw0.346 Mw0.324 Mw

From the pervious table we notice that the buses voltage in the voltage level improvement case the best of the three cases but we need to rise it more by another method. In three cases there is a change in the current and losses as shown in the next table :

MINIMUM LOAD

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND

MW Mvar MVA % PF ========= ========= ========= ============== Swing Bus(es): 4.911 2.232 5.395 91.0 Lagging Total Demand: 4.911 2.232 5.395 91.0 Lagging --------- --------- --------- --------------

Total Static Load: 4.850 2.114 Apparent Losses: 0.061 0.118

Total current 141 A .

VOLTAGE LEVEL IMPROVEMENT of MINIMUM LOAD

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND

M W Mvar MVA % PF ========= ========= ========= ============== Swing Bus(es): 4.931 1.676 5.208 94.7 Lagging Total Demand: 4.931 1.676 5.208 94.7 Lagging --------- --------- --------- -------------- Total Static Load: 4.874 1.565 Apparent Losses: 0.057 0.110

Total current 136 A .

Comparison between the case minimum load and Comparison between the case minimum load and voltage Level improvement of minimum loadvoltage Level improvement of minimum load

Bus#

Voltagebefore

Voltageafter

P.fbefore

p.fafter

bus20.3960.39891.7799.8Bus50.3940.39691.0099.4Bus60.3930.39591.1091.4Bus70.3950.39491.4091.4Bus80.3940.39591.4097.0Bus90.3930.39691.8099.8

Bus100.3940.39490.7091.7Bus110.3940.39491.7090.9Bus120.3940.39290.9097.8Bus130.3900.39490.9090.1Bus140.3930.39490.1096.5Bus150.3930.39392.3990.8Bus160.3930.39390.8093.5Bus170.3920.39490.0890.7Bus180.3930.39390.7097.7Bus200.3910.39491.4094.1Bus210.3940.39494.1098.8Bus220.3910.39387.9096.0Bus230.3910.39492.4092.6Bus240.3940.39492.6095.6

Bus

#Voltagebefore

Voltage

after

P.f

before

p.f

afterBus260.3930.39491.7093.3Bus280.3940.39593.3094.7Bus290.3940.39494.7093.0Bus300.3940.39393.0095.8Bus310.3920.39392.1895.5Bus320.3920.39392.3092.4Bus340.3930.39492.4098.9Bus350.3920.39292.1098.3Bus360.3890.39191.3098.1Bus370.3890.39391.4091.3Bus380.3930.39291.3093.7Bus390.3920.39293.7093.7Bus400.3920.39393.7097.1Bus420.3910.39288.9090.9Bus430.3920.39390.9092.8Bus450.3920.39292.8090.9Bus460.3910.39290.9095.4Bus480.3910.39292.6090.0Bus490.3910.39290.0092.2Bus500.3920.39392.2097.0Bus510.3920.39389.5093.1Bus520.3920.39393.1098.8

We use capacitor with two types:

•Fixed capacitor = 1.385 Mvar .•Variable capacitor (controlled ) = 1.36 Mvar

Economical studyEconomical study

1 .Economical study o f p.f improvementZ∆p= (∆p1-∆P 2)*T*140 $/MWhWe take tmax = 5550 h , then we calculate TT=8760(0.124+0.0001tmax)^2T=4000 hour

Z∆p = ( 0.36 – 0.346 ) * 4000 * 140 = 7840$ Saving in P.f penalties = (0.92 – 0.90) *65465 *140 * 0.02

=3666 $ We know that the cost of the capacitor is as follow-:

Fixed Cap=5000 $/MvarRegulated Cap=15000 $/Mvar

Zc = 0.22 * 5000 * 0.67 = 737 $ Total saving = saving in Δp +saving in power factor – Zc

= 7840 + 3666 – 737 = 10769 $

2. Economical study of voltage level improvement

Z∆p = (∆p1-∆P 2 )*T*140 $/MWhZ∆p= ( 0.36 – 0.324 ) * 4000 * 140 = 20160 $ Saving in P.f penalties = 3666$

S.P.B.P = investment = 0.67*5000 = 0.31 year Annual saving 10769

= 0.31 year *12 = 3.7 months

Fixed Cap=5000 $/MvarRegulated Cap=15000 $/MvarZc = 0.22 * 5000 * 1.385 + 0.22 * 15000 * 1.36

= 1524 + 3300 = 6012 $ Total saving = saving in Δp +saving in power factor – Zc

= 20160 + 3666 – 6012 = 17814. $

S.P.B.P = investment = 5000 * 1.385 + 15000 * 1.36 = 1.5 year Annual saving 17814

= 1.5 year * 12 = 18 months.

Two connection points and other Two connection points and other improvementimprovement

1. Two connection points without ring configuration.2. Two connection points and change main T.L without ring configuration.3. Influence of Load factor correction.4. Two connection points, change main T.L, P.f improvement and load factor correction without rings configuration.5. Two connection points, change main T.L, P.f improvement and load factor correction with rings configuration .

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND MW Mvar MVA % PF ======= ======= ========= ========== Swing Bus(es): 6.942 3.919 7.972 87.1 Lagging Generators: 5.000 2.000 5.385 92.8 Lagging Total Demand: 11.942 5.919 13.329 89.6 Lagging --------- --------- --------- -------------- Total Static Load: 11.693 5.096 Apparent Losses: 0.249 0.823

I swing 209 AI gen 93 A

Two connection points without ring configurationTwo connection points without ring configuration..

Bus

#

Voltage

nom

Voltage

act

bus20.4000.392

Bus50.4000.386

Bus60.4000.385

Bus70.4000.390

Bus80.4000.387

Bus90.4000.387

Bus100.4000.389

Bus110.4000.387

Bus120.4000.388

Bus130.4000.378

Bus140.4000.387

Bus150.4000.385

Bus160.4000.385

Bus170.4000.383

Bus180.4000.387

Bus200.4000.381

Bus210.4000.388

Bus

#

Voltag

e

nom

Voltage

act

Bus220.4000.381

Bus230.4000.382

Bus240.4000.390

Bus260.4000.387

Bus280.4000.389

Bus290.4000.390

Bus300.4000.388

Bus310.4000.385

Bus320.4000.386

Bus340.4000.387

Bus350.4000.386

Bus360.4000.378

Bus370.4000.377

Bus

#

Voltag

e

nom

Voltage

act

Bus380.4000.387

Bus390.4000.385

Bus400.4000.385

Bus420.4000.383

Bus430.4000.385

Bus450.4000.387

Bus460.4000.384

Bus480.4000.382

Bus490.4000.384

Bus500.4000.385

Bus510.4000.386

Bus520.4000.387

Bus540.4000.386

Bus550.4000.389

Bus560.4000.388

Two connection points and change main Two connection points and change main T.L without ring configurationT.L without ring configuration..

In this case we notice the difference in the losses from the previous case as shown :

The losses before change main T.L = 0.249 Mw .The losses after change main T.L = 0.236 Mw .

T2(400KVA)to T40(630KVA)

T8(400KVA)to T34(630KVA)

T7(400KVA)to T47(630KVA)

T2T40T8T34T7T47Bus# 13737383630

L.F before10733104399844L.F after655364596070

Voltage before

387393387394388393

Voltage after

391390391392392389

influence of Load factor correctioninfluence of Load factor correction. . Some transformers are over loaded T2,T7,T8… while others are

operating at light load as T40,T34 , T47. To have a good transformer loading the load factor should be greater than 0.6 In order to make the transformer works on a better efficiency

We make the following correction and we show the influence

Two connection points , change main T.LTwo connection points , change main T.L, , P.f improvement and load factor correction without P.f improvement and load factor correction without

ring configurationring configuration. .

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND

MW Mvar MVA % PF ======= ======= ========= ========== Swing Bus(es): 6.942 3.919 7.972 87.1 Lagging Generators: 5.000 2.000 5.385 92.8 Lagging Total Demand: 11.942 5.919 13.329 89.6 Lagging --------- --------- --------- -------------- Total Static Load: 11.693 5.096 Apparent Losses: 0.249 0.823

I swing 209 AI gen 93 A

Bus

#

Voltage

nom

Voltage

act

bus20.4000.397

Bus50.4000.391

Bus60.4000.392

Bus70.4000.389

Bus80.4000.389

Bus90.4000.388

Bus100.4000.390

Bus110.4000.388

Bus120.4000.389

Bus130.4000.389

Bus140.4000.388

Bus150.4000.386

Bus160.4000.390

Bus170.4000.387

Bus180.4000.388

Bus200.4000.389

Bus210.4000.389

Bus

#Voltage

nom

Voltage

act

Bus220.4000.388

Bus230.4000.390

Bus240.4000.391

Bus260.4000.392

Bus280.4000.391

Bus290.4000.391

Bus300.4000.386

Bus310.4000.390

Bus320.4000.387

Bus340.4000.388

Bus350.4000.388

Bus360.4000.390

Bus370.4000.389

Bus380.4000.389

Bus

#Voltag

e

nom

Voltage

act

Bus390.4000.386

Bus400.4000.386

Bus420.4000.391

Bus430.4000.390

Bus450.4000.388

Bus460.4000.390

Bus480.4000.384

Bus490.4000.390

Bus500.4000.387

Bus510.4000.391

Bus520.4000.389

Bus540.4000.388

Bus550.4000.390

Bus560.4000.396

Two connection points , change main T.L , P.f Two connection points , change main T.L , P.f improvement and load factor correction improvement and load factor correction with ringwith ring

configurationconfiguration. .

SUMMARY OF TOTAL GENERATION, LOADING & DEMAND

MW Mvar MVA % PF

========= ========= ========= ============== Swing Bus(es): 7.222 2.291 7.577 95.3 Lagging Generators: 5.000 2.000 5.385 92.8 Lagging Total Demand: 12.222 4.291 12.954 94.3 Lagging --------- --------- --------- -------------- Total Static Load: 12.051 3.559 Apparent Losses: 0.172 0.732..

Comparison between voltages of  

1. the origin case . 2. voltage level improvement case . 3. Two connection points without ring. 4 . Two connection points , change main T.L , P.f improvement and load

factor correction without ring configuration . 5 . Two connection points , change main T.L , P.f improvement and load

factor correction with ring configuration .

Two connection points , without ring

Two connection points , change main T.L

without ring

Two connection points , change main T.L , P.f improvement and load factor correction without ring configuration

Two connection points , change main T.L , P.f improvement and load factor correction with ring configuration

losses0.2490.2360.2170.172

When we put rings We noticeThat the voltages increases in average and the losses decrease

The optimum case Two connection points , change main T.L , P.f improvement and load factor correction with ring configurationBecause: ** less losses and best voltages

Low Tension analysis:

Most of the power losses …. Voltage drop happens on the low voltage network … That because of high currents … Analysis will be over the longest feeder of a certain Transformer which is T 23 … T 23 has three feeders and loaded by 465 A Three feeders •Feeder 1 = 134 KVA •Feeder 2 = 122 KVA•Feeder3 = 98.5 KVA

We note that drop voltages in low tension between We note that drop voltages in low tension between ( 2.5-5)%( 2.5-5)%

As shown in the next pictureAs shown in the next picture