International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 4
April 2017
AN APPLICATION OF MS-EXCEL FOR COMPUTATION
OF VARIOUS TRANSFORMER PARAMETERS
Prof. Manan M. Desai4
Assistant Professor DegreeElectrical Engineering
Dr. Subhash Technical Campus, Junagadh
Ghadiya Kishan S.1
Student of Electrical
Department
Dr. Subhash Technical Campus
Junagadh
Gohel Tushar M.2
Student of Electrical
Department
Dr. Subhash Technical Campus
Junagadh
Baraiya Yogesh3
Student of Electrical
Department
Dr. Subhash Technical Campus
Junagadh
ABSTRACT
Transformer is a very important part of any substations, which affects overall costing of transmission and distribution
budgets. So, it is necessary to design economical, viable, low weight, small size efficient transformer.The design of
transformer depend to large extent on the specific requirement of the customer. The main objective of our project is to
develop a program for transformer design using Excel sheet. This Programming has ability to execute many difficult and
reiterative calculations and step-wise procedure leading to a design that satisfies all input specification.With the
Calculation technologies in the power industry, new references addressing new technologies are coming to the market.
Based on this fact, there is an urgent need to keep track of international experiences and activities taking place in the
field of modern transformer design. The complexity of transformer design demands reliable and rigorous solution
methods. A survey of current research reveals the continued interest in application of advanced techniques for
transformer design optimization. This paper conducts a literature survey and reveals general backgrounds of research
and developments in the field of transformer design and optimization for the past 30 years, based on more than 200
published articles, 25 transformer books, and 50 standards.[1]
Keywords :-Microsoft excel, visual basic, power system analysis, equivalent circuits, experimental methods,
numerical techniques, standards, survey, transformer books, transformer design optimization.
1. Introduction
Transformer design is a complex task in which engineers have to ensure that compatibility with the imposed
specifications is met, while keeping manufacturing costs low. Moreover, the design methodology may vary
significantly according to the transformer type (distribution or power transformer) and its operating frequency
(ranging between 50/60 Hz and a few MHz), while many alterations according to the core constructional
characteristics, the cooling method, or the type of the magnetic material may be encountered. This paper
provides an overview of research, development and application of various computational methods for
transformer design, based on an extensive number of published papers. The review is divided into two major
sections: research efforts focusing on the prediction and/or optimization of specific transformer characteristics
(mainly losses and short-circuit impedance) and techniques adopted for global transformer design
optimization, taking into account all the relevant performance parameters.[2]
2. Methodology Design
With the rapid development of the digital computer, designers are no longerassist to their performance of the
routine calculations. Computer is widely use in optimized of transformer designwithintheir matter of the
seconds. We have make an excel sheet that includes transformer parameter calculation easily.
43
Prof. Manan M. Desai, Ghadiya Kishan S., Gohel Tushar M., Baraiya Yogesh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 4
April 2017
These are the input parameters of transformer :• KVA rating of Transformer
• Primary voltage
• Secondary voltage
• No load losses
• No load current
• Full load losses
• Impedance voltage
• LV resistance in mili ohms
• HV resistance in ohms
• Amb temperature
• Total Connected Load on Transformer
Above transformer data include in excel sheet and we got the calculation of transformer parameters.
3. CASE STUDY
This section presents the mathematical formulation of the objective function, design variables, and design
constraints for distribution transformer design optimization. This technique is integrated in excel environment,
using suitable graphical user interface. The transformer inputs involves design parameters, such as rated
power, voltages, etc., comprises of the upper/lower limits and the initial value of the design. For optimizing
the transformer design is based on the minimization of the overall transformer cost function.
3.1Formula
HV Full load current = VA / (1.732xVolt)
LV Full load current = VA / (1.732xVolt)
HV Side I2R losses = I²R x1.5
LV Side I²R losses = I²R x0.5x3
Total I² R losses @ Amb temp = Hv losses + Lv losses
Total Stray losses @ Amb temp = Measured losses -I² R losses
I² R losses @75° c temp = ((225+75) x losses) / (225+ Amb temp)
Stray losses @ 75° c temp = ((225+Amb temp)(Stray losses at amb)) / 300
Total Full load losses at @75° c = I²R losses at 75°c+Stray losses at 75°c
Total Impedance at ambient temp = (Imp voltage x 1.732) / Full load current
Total Resistance at ambient temp = I²R losses / I²
Total Reactance (X) = SQRT(Impedance ²- Resitance ²)
Resistance at@ 75° c = (300 x resistance at ambient ) /(225+Amb temp)
Impedance at 75° c = SQRT(R² at 75 + X²)
Percentage Impedance = (Z at 75° c x I x 100)/V1
Percentage Resistance = ( R 75° c x I x 100)/V1
Percentage Reactance = (X x I x 100) / V1
Regulation at Unity P.F = (%R cosø+%Xsinø)
Regulation at 0.8 p.f. =(%R cosø+%Xsinø)+1/200(%R sinø-%Xcosø)2"
Efficiency at Unity P.F
o At 125 % of Transformer Loading =
(Kva x 1.25 x 100)/((kva x 1.25)+(I²R losses x 1.25²)+(No Load Losses))
 Efficiency at 0.8 P.F
o At 125 % of Transformer Loading =
(Kva x 1.25xp.f x 100)/((kvaxp.fx 1.25)+(I²R losses x 1.25²)+(No Load Losses))
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3.2 Parameter Caculations
 I2R Losses :1. LV Full load current = (KVA rating of Transformer)/( Secondary voltage*1.732)
44
Prof. Manan M. Desai, Ghadiya Kishan S., Gohel Tushar M., Baraiya Yogesh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 4
April 2017
2.
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= (16000)/(11000*1.732) = 0.84 Amps
LV Full load current = (KVA rating of Transformer)/( Secondary voltage*1.732)
= (16000)/(433*1.732) = 21.33 Amps
HV Side I²R losses =〖(HV Full Load Current)〗^2* HV resistance*1.5
= (0.84*0.84)*215*1.5 = 227.80 Watts
LV Side I²R losses =〖(LV Full Load Current)〗^2* LV resistance*1.5
= (21.33*21.33)*219.16mΩ*1.5 = 149.56 Ohms
Total I² R losses @ Amb temp = HV Side I²R losses + LV Side I²R losses
= (227.80)+(149.56) Ω = 377.43 Ohms
Total Stray losses @ Amb temp= (LV Side resistance in mili Ω) - Total I² R losses @ Amb temp
= (219.16mili ohm’s) –(377.43 watts) = 16.57watts
Total I² R losses @75`C Amb temp = ((225+75) total I²R losses) / (225+ Amb temp)
= ((225+75) x337.43) / (225+ 30) = 441.52Watts
Stray losses @ 75° c temp = ((Total Stray losses @ Amb temp)*(235+ Amb temperature))/(310)
= ((16.57watts)*(235+ 30))/(310) = 14.16Watts
Total Full load losses at @75° c =
=( Total I² R losses @75`C Amb temp)+( TotalStray losses @ 75° c temp)
= (441.52Watts)+(14.16Watts) = 455.9 Watts
Total Impedance at ambient temp = ( Impedance voltage*1.732)/( HV Full load current)
= 480*1,732)/(0.84) = 989.54 Ohms
Total Resistance at amb temp = ( Total I²R losses @ Amb temp)/((HV Full Load Current)2 )
= ( 377.43)/(0.84)2 = 535.15 Ohms
Total Reactance (X) = SQRT(Impedance ²- Resistance ²)
= SQRT((989.94) ²- (535.15) ²) = 832.82Ω
Resistance at@ 75° c = (310 *total resistance at ambient ) /(225+Amb temp)
= (310 *535.15) /(225+30) = 625.03Ω
Impedance at@ 75° c = SQRT(R² at 75 + X²)
= SQRT((625)2 + (832.82)2 ) = 1041.88Ω
Percentage Impedance = (Impedance*0.5774*HV Load Current*100)/(Primary Voltage)
= (1041.88*0.5774*0.84*100)/(11000) =4.59%
16. Percentage Resistance = (Resistance at 75 c*0.5774*HV Load Current*100)/(Primary Voltage)
= (535.15*0.5774*0.84*100)/(11000) =2.76%
17. Percentage Reactance = (Total Reactance *0.5774* HV Load Current *100)/(Primary Voltage)
= (832.82Ω *0.5774* 0.84*100)/(11000) =3.67%
45
Prof. Manan M. Desai, Ghadiya Kishan S., Gohel Tushar M., Baraiya Yogesh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 4
April 2017
 Regulation Calculation:1. Regulation at Unity P.F = (%R cosø+%Xsinø)
= ((2.75*0.8)+ (3.67*0.6)) = 2.76
2. Regulation at 0.8 P.F = (%R cosø+%Xsinø)+1/200(%R sinø-%Xcosø)2
=( 2.75 ∗ 0.8 + (3.67 ∗ 0.6)) + 0.005((2.75 ∗ 0.6) + (3.67 ∗ 0.8))2
= 4.43%
 Efficiency Calculation:1. Efficiency at Unity P.F = (KVA*1.25*100)/((KVA* 1.25)+(I²R losses*1.25²)+(No Load Losses))
= (16000*1.25*100)/((16000*1.25)+(377.45*1.25²)+(72)*100 = 96.80%
2. Efficiency at 0.8 P.F =
= (KVA x 1.25xp.f x 100)/((KVA xp.fx 1.25)+(I²R losses x 1.25²)+(No Load Losses
= (16000*1.25*.8*100)/((16000*1.25*0.8+(377.45*0.8*1.25²)+(72)*100 = 99.52%
4. RESULT
Now a day to calculate transformer parameters method is very lengthy, hard and it take a so much time of
operators. So, we make this project to calculate transformer parameter and it is very easy and give output
within there matter of seconds.
 I²R losses Calculation:Theoretical Calculation
Practical Calculation
HV Full load current :- 0.83 A
HV Full load current :- 0.84 A
LV Full load current :- 21 A
LV Full load current :- 21.33 A
HV Side I²R losses :- 225 W
HV Side I²R losses :- 227.80 W
LV Side I²R losses:- 150 W
LV Side I²R losses:- 149.63 W
Total I² R losses @ ambient temp:- 376 W
Total I² R losses @ ambient temp:- 377.43 W
Total Stray losses @ ambient temp:- 15 W
Total Stray losses @ ambient temp:- 16.57 W
I² R losses @75° c temp:- 441
I² R losses @75° c temp:- 441.52 W
Stray losses @ 75° c temp:- 15 W
Stray losses @ 75° c temp:- 14.16 W
Total Full load losses at @75° c :- 455 W
Total Full load losses at @75° c :- 455.69 W
Total Impedance at ambient temp:- 989 Ω
Total Impedance at ambient temp:- 989.94 Ω
Total Resistance at ambient temp:- 535 Ω
Total Resistance at ambient temp:- 535.15 Ω
Total Reactance (X):- 831 Ω
Total Reactance (X):- 832.82 Ω
Resistance at@ 75° c:- 626.35 Ω
Resistance at@ 75° c:- 626.03 Ω
Impedance at 75° c :- 1041.20 Ω
Impedance at 75° c :- 1041.88 Ω
Percentage Impedance:- 4.60 %
Percentage Impedance:- 4.59 %
Percentage Resistance :- 2.65 %
Percentage Resistance :- 2.67 %
Percentage Reactance :- 6.66 %
Percentage Reactance :- 3.67 %
46
Prof. Manan M. Desai, Ghadiya Kishan S., Gohel Tushar M., Baraiya Yogesh
International Journal of Electronics, Electrical and Computational System
IJEECS
ISSN 2348-117X
Volume 6, Issue 4
April 2017
 Regulation Calculation :Theoretical Calculation
Regulation at P.F of unity :- 2.75 %
Regulation at P.F of 0.8 :- 4.43 %
Practical Calculation
Regulation at P.F of unity :- 2.76 %
Regulation at P.F of 0.8 :- 4.43 %
 Efficiency Calculation :Efficiency at P.F of Unity:At Transformer Loading 125% :- 96.75 %
Efficiency at P.F of 0.8
At Transformer Loading 125% :- 99.50 %
Efficiency at P.F of Unity:At Transformer Loading 125% :- 96.80 %
Efficiency at P.F of 0.8
At Transformer Loading 125% :- 99.52 %
5. CONCLUSION
In this projectwe got the information and practical knowledge about Transformer. We got the knowledge
about different type of transformer testing, I² R loss, efficiency, regulation, outer and inner part of transformer
like core, winding, relay etc. We have make an excel sheet that includes transformer parameter calculation
easily. Because all calculations is done by there programming, by human errors is eliminated which turn
eliminate cost associated by these.These project are very useful for industrial and power supplier. by use this
software they not need any external document require.
6. REFERENCES
[1] Eleftherios I. Amoiralis, Marina A. Tsili,and Antonios G. Kladas,IEEETransactions on Power Delivery. November
2009 DOI:10.1109/TPWRD.2009.2028763. Source: IEEE Xplore
[2] Eleftherios I. Amoiralis, Marina A. Tsilia, Pavlos S. Georgilakis,Journalof optoelectronics and advanced materials
Vol. 10, No. 5, May 2008, p. 1149 – 1158
[3] K. Zakrzewski, B. Tomczuk, and D. Koteras, “Simulation of forces and 3-D field arising during power
autotransformer fault due to electric arc in HV winding,” IEEE Trans. Magn., vol. 38, no. 2, pp. 1153–1156, Mar.
2002.
[4] American Journal of Engineering Research (AJER) e-ISSN : 2320-0847 p-ISSN : 2320-0936 Volume-4, Issue-2, pp133-145
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Prof. Manan M. Desai, Ghadiya Kishan S., Gohel Tushar M., Baraiya Yogesh