Modeling of Electric Field Around 100 MVA 150/20 kV Power Transformatorusing Charge Simulation Method


 

 

Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 
 

Mechatronics, Electrical Power, and 
Vehicular Technology 

 
e-ISSN: 2088-6985 
p-ISSN: 2087-3379 

Accreditation Number: 432/Akred-LIPI/P2MI-LIPI/04/2012 

 

 

www.mevjournal.com 
 

© 2013 RCEPM - LIPI All rights reserved 
doi: 10.14203/j.mev.2013.v4.33-40 

MODELING OF ELECTRIC FIELD AROUND  
100 MVA 150/20 KV POWER TRANSFORMATOR 

USING CHARGE SIMULATION METHOD 
 

Noviadi Arief Rachman a,*, Agus Risdiyanto a, Ade Ramdan b 
aResearch Centre for Electrical Power and Mechatronics, Indonesian Institute of Sciences 

Kompleks LIPI Gd. 20, Lt 2, Jl. Sangkuriang, Bandung, Indonesia 
bResearch Center for Informatics, Indonesian Institute of Sciences 
Kompleks LIPI Gd. 20, Lt. 3, Jl. Sangkuriang, Bandung, Indonesia 

 
Received 8 April 2013; received in revised form 21 May 2013; accepted 21 May 2013 

Published online 30 July 2013 
 

Abstract 
Charge Simulation Method is one of the field theory that can be used as an approach to calculate the electromagnetic 

distribution on the electrical conductor. This paper discussed electric field modeling around power transformator by using Matlab 
to find the safety distance. The safe distance threshold of the electric field to human health refers to WHO and SNI was 5 kV/m. 
The specification of the power transformator was three phases, 150/20 kV, and 100 MVA. The basic concept is to change the 
distribution charge on the conductor or dielectric polarization charge with a set of discrete fictitious charge. The value of discrete 
fictitious charge was equivalent to the potential value of the conductor, and became a reference to calculate the electric field 
around the surface contour of the selected power transformator. The measurement distance was 5 meter on each side of the 
transformator surface. The results showed that the magnitude of the electric field at the front side was 5541 V/m, exceeding the 
safety limits. 

 
Keywords: electric field, charge simulation method, discrete charge, power transformator. 

 
I. INTRODUCTION 

The electric field is an area that is still 
influenced by the electrical properties of a 
particular charge. An electric field presents in 
any region where a charged object experiences an 
electric force.  This is a fancy way of saying that 
the only way we can conclude the present of 
electric field is by performing a test charge on 
that spot. In nature, the electric field generated 
bythe natural formation of electrical charges in 
the atmosphere associated with lightning. The 
electric field also exists due to the electrical 
equipment such as generators, transformators, 
transmission lines, distribution lines, and other 
electric and electronic equipment. However, the 
influence of an electric field around high voltage 
equipment is greater than the effect of electric 
fields that exist in nature. The existence of an 
electric field can indirectly cause problems to 
human health. It is depending on how powerful 
electric field and magnetic field exposed to the 

human body that can cause problems. Population 
growth and technological change have led to 
increase in demand for electrical energy in larger 
quantities. This causes enhancement of electric 
field pollution in the urban and the work 
environments [1]. 

As it is stated before that the electric field can 
affect human health, it is also shown risk of 
cancer death in children living near the 
transmission line of high voltage [2]. In the 1960 
and early 1970, the Soviet Union reported health 
effects experienced by their workers in high 
voltage switch yard. Within several months the 
first 500 kV substations operated in the Soviet 
Union, maintenance workers complained about 
headaches, sexual potency reduction, and general 
ill health. The electric field was assumed to be 
responsible for the health complaints. Personnel 
working with 500 kV and 750 kV lines were 
compared to the workers at 110kV and 220 kV 
substations. Maximum intensities within the 500 
kV and 750 kV switchyard were generally 
between 15 kV/m and 25 kV/m and biological 
effects were reported above 5 kV/m[3].  

* Corresponding Author: Tel: 022-2503055; Fax: 022-2504773 
E-mail: opay_23@yahoo.com 

http://dx.doi.org/10.14203/j.mev.2013.v4.33-40


N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 

 

34 

According to the WHO standard in 1990, 
boundary electric field allowed in the public 
areas for 24 hours per day is 5 kV/m [4].The 
Indonesian government adopted the IRPA and 
WHO recommendations which then included in 
the Indonesian National Standards (SNI) 
concerning the safety limit for the influence of a 
50-60 Hz electric field, as shown in Table 1. 

There is a lot of high voltage electrical 
equipment used in electric power systems one of 
which is the power transformator. Power 
transformator is a device that is used to convert 
inbound electricity or voltage to a higher or lower 
value in order to accommodate the current flow 
needed for specific purposes. Power 
transformator are a normal component in the 
power grids of many nations, making it possible 
to regulate the transfer of power to residences 
and commercial buildings without overloading 
the circuitry in those structures [5]. There are 
various levels of voltage used in power 
distribution systems, i.e. Extra High Voltage 
(500/150 kV), High Voltage (150/70 kV), 
Medium Voltage (150/20 kV, 70/20 kV), and 
Low Voltage (20 kV/380 V). Since the area 
around the power transformator has a large 
electric field, it is important to determine the 
safety distance from electric field effect for 
human health according to WHO and SNI.  

This paper discusses the electric field that is 
produced by power transformator 100MVA, 
150/20 kV, 50 Hz, from different sides of a 
surface with reference to each measurement 
distance of 5 meters. The modeling of electric 
field used the Charge Simulation Method (CSM) 
which applied to the Matlab. The aims is to know 
the magnitude of electric field generated by 
influence of power transformator 100 MVA, 
150/20 kV, 50 Hz, to a safe distance according to 
WHO standard. 

 
II. BASIC THEORY 
A. Electric Field 

The electric field can be analyzed as an 
electrostatic field and magneto static, the electric 
field generated by AC-current is quasi-static [6]. 

It also produced by the voltage from electrical 
equipment. The strength of an electric field at a 
given point in space near an electrically charged 
object is proportional to the amount of charge on 
the object, and inversely proportional to the 
distance between the point and the object. 

Electric fields strength are usually denoted by 
the symbol E, and it is a vector that has both 
magnitude and direction, as defined below [7]: 

𝐸𝐸 = 𝑄𝑄
4𝜋𝜋𝜋𝜋 0𝑅𝑅2

 . 𝛼𝛼𝑅𝑅 (1) 

where 
E : Electric field strength (V/m) 
Q : Point charge (Coloumb) 
𝜋𝜋0 : Permittivity dielectric  
R : Distance between Point charge and point P 
 
If described in Cartesian coordinates, the electric 
field E of a point charged +Q and lies in the 
coordinates of the point P (x, y, z) seen as vectors 
as shown in Figure 1. 

If there are many charges on the different 
positions, the fields caused by n point charges 
can be written as follow [8]: 

𝐸𝐸(𝑟𝑟) = 𝑄𝑄1
4𝜋𝜋𝜋𝜋 0 |𝑟𝑟−𝑟𝑟1 |2

 . 𝒶𝒶1 +
𝑄𝑄2

4𝜋𝜋𝜋𝜋 0 |𝑟𝑟−𝑟𝑟2 |2
. 𝒶𝒶2 +

⋯ + 𝑄𝑄𝑛𝑛
4𝜋𝜋𝜋𝜋 0 |𝑟𝑟−𝑟𝑟𝑛𝑛 |2

. 𝒶𝒶𝑛𝑛  (2) 

where 
E(r) : electric field strength at point r (V/m) 
𝑄𝑄𝑛𝑛  : point charge at point n (Coloumb) 
𝜋𝜋0 : permittivity dielectric  
r : the position of the observation point 
𝑟𝑟𝑛𝑛  : the position of the sources 
𝒶𝒶𝑛𝑛  : unit vector n. 
 
For homogeneous line charge with charge density 
per unit length 𝜌𝜌𝐿𝐿, then equation of the electric 
field above will be shown in eq. (3): 

𝐸𝐸(𝜌𝜌) =
𝑄𝑄𝐿𝐿

2𝜋𝜋𝜋𝜋0𝜌𝜌𝐿𝐿
 . 𝒶𝒶𝜌𝜌  (3) 

 
 

Figure 1. The point Pis The Vector Sum of The Electric 
field due to charge+Q 

 

Table 1. 
The threshold electric field and magnetic field 50-60 Hz 

No Classification Electric Field (kV/m) 
1 Working area: 

 - Working time 
 - Short time 

 
10 
30 (0 - 2 hour/day) 

2 Public area : 
 - 24 hour/day 
 - Few hour/day 

 
5 
10 

 



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 
 

 

35 

where 
E(𝜌𝜌) : electric field strength due to line  charge 

(V/m) 
𝑄𝑄𝐿𝐿 : line charge (Coloumb) 
𝜋𝜋0 : permittivity dielectric  
𝜌𝜌𝐿𝐿 : length (m) 
 
B. Charge Simulation Method (CSM) 

Charge Simulation Method (CSM) is a 
method that used as an approach to distribution 
electric field problem induced by the charged 
conductor CSM considered a practical method 
for calculating the fields and from its simplicity 
in representing the equipotential surfaces of the 
electrodes, its application to unbounded 
arrangements whose boundaries extend to infinity 
and its direct determination to the electric field 
[9]. The magnitudes of fictitious discrete charges 
are equivalent to the potential value of the 
conductor and used as a reference to calculate the 
electric field around the contour of the conductor 
surface that selected. Once the values and 
positions of simulation charges are known, the 
potential and field distribution anywhere in the 
region can be computed easily [10]. 

In many practical problems of electrostatic, 
charge always located near a conductor. An 
electron released by an electrode and a power 
transmission line suspended over the earth 
conductor is an example of a commonly 
encountered. Let’s review the case of a point 
charge near an infinite plane conductor, as shown 
in Figure 3,in determining the potential +q with 
height d using Poisson equation with z > 0, and 
boundary condition V = 0 at z = 0 and at infinity 
[11]. 

Since there is no conductor, the solution to 
find the point charge in free space is as follows: 

𝑉𝑉(𝑥𝑥, 𝑦𝑦, 𝑧𝑧) = 𝑞𝑞
4𝜋𝜋𝜋𝜋

� 1
�𝑥𝑥 2 +𝑦𝑦2 +(𝑧𝑧−𝑑𝑑)2

� (4) 

where 
𝑉𝑉 : Electric potential (V) 
𝑞𝑞 : point charge (Coloumb) 
𝜋𝜋 : Permittivity dielectric 

 
Potential function V on equation (4) 

accomplishes Poisson’s equation for z > 0 with 
boundary condition V = 0. However, the 
potential is not zero on z = 0. So the solution of 
case above can be shown in Figure 4 as follow: 

The potential is expressed as: 

𝑉𝑉 (𝑥𝑥, 𝑦𝑦, 𝑧𝑧) = 𝑞𝑞
4𝜋𝜋𝜋𝜋

� 1
�𝑥𝑥 2 +𝑦𝑦2 +(𝑧𝑧−𝑑𝑑)2

−

1𝑥𝑥2+𝑦𝑦2+𝑧𝑧+𝑑𝑑2 (5) 

The electro static potential in area z > 0 is super 
position of point charge +q and its image –q. 
Once the potential function is obtained, the 
electric field can be calculated directly from the 
potential by using equation (6) [12]: 

𝐸𝐸 = −∇𝑉𝑉 = 𝑞𝑞
4𝜋𝜋𝜋𝜋

� 𝑥𝑥�𝑥𝑥+ 𝑦𝑦�𝑦𝑦+ 𝑧𝑧̂
(𝑧𝑧−𝑑𝑑)

(𝑥𝑥 2 + 𝑦𝑦2 +(𝑧𝑧−𝑑𝑑)2 )
3

2�
−

𝑥𝑥𝑥𝑥+ 𝑦𝑦𝑦𝑦+ 𝑧𝑧𝑧𝑧−𝑑𝑑𝑥𝑥2+ 𝑦𝑦2+𝑧𝑧+𝑑𝑑232 (6) 

C. Two Dimensional Charge Field 
Simulation of two-dimensional charge field 

can be calculated with some line charges depicted 
on the x and y axis, with coefficients of line 
charge can be written by equation (7)[13]: 

𝑃𝑃𝑛𝑛 =  
1

2𝜋𝜋𝜋𝜋
 1n �

(𝑥𝑥−𝑥𝑥𝑛𝑛 )2 + (𝑦𝑦−𝑦𝑦𝑛𝑛 )2

(𝑥𝑥−𝑥𝑥𝑛𝑛 )2 + (𝑦𝑦+𝑦𝑦𝑛𝑛 )2
 (7) 

Where 𝜋𝜋 is permittivity, (𝑥𝑥𝑛𝑛 , 𝑦𝑦𝑛𝑛 ) is coordinate 
online charge which forms two-dimensional 
plane, and (x, y) is the coordinate of measurement 
point. In the Gauss theorem explained that the 
line charge located at y = 0 (ground), the 
potential is zero. By adjusting the boundary 
conditions on the components of the x and y 
coordinates that form a two-dimensional plane, 
then the electric field at any point due to n 
charges that form two-dimensional plane can be 
calculated by the following equation: 

For n conductor, the potential of each is [11]: 

𝑉𝑉1 =
𝜌𝜌1

2𝜋𝜋𝜋𝜋
 1n

𝐿𝐿11′
𝐿𝐿11

+ ρ2
2πε

1n
𝐿𝐿12′
𝐿𝐿12

+
ρ3

2πε
1n

𝐿𝐿13′
𝐿𝐿13

+ ⋯ + ρ𝑛𝑛
2πε

1n
𝐿𝐿1𝑛𝑛′
𝐿𝐿1𝑛𝑛

 (8) 

 
 

Figure 2. Discretization charges on the rod conductor 
 

 

 
 

Figure 3. A point charge +q near infinite conductor 
 

 +q

dx

z



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 

 

36 

𝑉𝑉2 =
𝜌𝜌1

2𝜋𝜋𝜋𝜋
 1n

𝐿𝐿21′
𝐿𝐿21

+ ρ2
2πε

1n
𝐿𝐿22′
𝐿𝐿22

+
ρ3

2πε
1n

𝐿𝐿23′
𝐿𝐿23

+ ⋯ + ρ𝑛𝑛
2πε

1n
𝐿𝐿2𝑛𝑛′
𝐿𝐿2𝑛𝑛

 (9) 

𝑉𝑉3 =
𝜌𝜌1

2𝜋𝜋𝜋𝜋
 1n

𝐿𝐿31′
𝐿𝐿31

+ ρ2
2πε

1n
𝐿𝐿32′
𝐿𝐿32

+
ρ3

2πε
1n

𝐿𝐿33′
𝐿𝐿33

+ ⋯ + ρ𝑛𝑛
2πε

1n
𝐿𝐿3𝑛𝑛′
𝐿𝐿3𝑛𝑛

 (10) 

𝑉𝑉𝑛𝑛 =
𝜌𝜌1

2𝜋𝜋𝜋𝜋
 1n

𝐿𝐿n 1′
𝐿𝐿n 1

+ ρ2
2πε

1n
𝐿𝐿n 2′
𝐿𝐿n 2

+
ρ3

2πε
1n

𝐿𝐿n 3′
𝐿𝐿n 3

+ ⋯ + ρ𝑛𝑛
2πε

1n
𝐿𝐿n𝑛𝑛′
𝐿𝐿n𝑛𝑛

 (11) 

The above equation can be written in matrix 
format follows: 

⎣
⎢
⎢
⎢
⎡
V1
V2
V3
⋮

Vn⎦
⎥
⎥
⎥
⎤

=

⎣
⎢
⎢
⎢
⎡
P11 P12 P13 … P1n
P21 P22 P23 … P3n
P31
⋮

Pn 1

P32
⋮

Pn 2

P33 … P3n
⋮ ⋮ ⋮

Pn 3 … Pnn ⎦
⎥
⎥
⎥
⎤

.

⎣
⎢
⎢
⎡
ρ1
ρ2
ρ3
⋮
ρn⎦
⎥
⎥
⎤
 (12) 

or 

[𝑉𝑉] =  [𝑃𝑃]. [𝜌𝜌] (13) 
Thus, the line charge can be found using the 
equation: 

[𝜌𝜌] =  [𝑃𝑃]−1. [𝑉𝑉] (14) 
where: 
V =potential phase  
P  =matrix coefficients of Maxwell  
𝜌𝜌  =line charge 
 
D. Application of (CSM) for the 

Computation of the Electric Field in 
Power Transformator 

For three-phase power transformator, where 
the number conductors more than one (R, S, T on 
the high voltage side and the R, S, T on the low 
voltage side), the magnitude of the potential at a 
point is the number of potential caused by their 
conductor on each side of the high voltage 150 
kV and low voltage 20 kV potential 
transformator windings shown in Figure 5. 
 

III. METHODOLOGY 
A. Specification of Measurement 

The specifications of power transformator that 
used in simulation are: 
- Voltage (V1(rms )) : 150,000 V (150kV) 
- Voltage (V2(rms )) : 20,000 V (20kV) 
- Transformator dimension: 2.5 x 1.5 x 1 m 
- Conductor distance to V1:1.25 m 
- Conductor distance to V2:0.5 m 
 

The Software that used in the simulation is 
Matlab 2007. Electric field strength is expressed 
in the vertical axis and horizontal axis, each with 
real and imaginary parts, or with magnitude and 
phase angle. 

 
- Vertical axis of electric field strength: 

𝐸𝐸𝑦𝑦 = 𝐸𝐸𝑟𝑟𝑦𝑦 +  j𝐸𝐸𝑖𝑖𝑦𝑦  or 𝐸𝐸𝑦𝑦 =  �𝐸𝐸𝑦𝑦� < φ𝑡𝑡𝑦𝑦  

- Vertical axis of electric field strength: 

𝐸𝐸𝑥𝑥 = 𝐸𝐸𝑟𝑟𝑥𝑥 +  j𝐸𝐸𝑖𝑖𝑥𝑥  or 𝐸𝐸𝑥𝑥 =  |𝐸𝐸𝑥𝑥 | < φ𝑡𝑡𝑥𝑥  

Voltage equations of each phase are: 

𝑉𝑉𝑅𝑅1 =
𝑉𝑉01
√3

√2[cos 0 +  𝑗𝑗 sin 0] 

𝑉𝑉𝑆𝑆1 =
𝑉𝑉01
√3

√2[cos −120 +  𝑗𝑗 sin −120] 

𝑉𝑉𝑇𝑇1 =
𝑉𝑉01
√3

√2[cos 120 +  𝑗𝑗 sin 120] 

𝑉𝑉𝑅𝑅2 =
𝑉𝑉01
√3

√2[cos 0 +  𝑗𝑗 sin 0] 

𝑉𝑉𝑆𝑆2 =
𝑉𝑉01
√3

√2[cos −120 +  𝑗𝑗 sin −120] 

𝑉𝑉𝑇𝑇2 =
𝑉𝑉01
√3

√2[cos 120 +  𝑗𝑗 sin 120] 

+q

dx

z

-q

d

 
Figure 4. A point charge +q and its image -q 

 

 
Figure 5. Front view of 3 phasa power transformator, 
100 MVA 150 kV/20 kV 

 

1,5 m

1,25 m

Trafo 3 Fasa, 150/20 kV
100 MVA, 5o Hz

2,5 m

1,5 m

0,5 m

1
3 Phasa Power Transformator
150/20 kV, 100 MVA, 50 Hz



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 
 

 

37 

B. Boundary Conditions 
The boundary conditions are determined by 

adjusting the position of a point charge 
(discretization) with layout coordinates (x,y) on 
the boundary dimensions of the system to be 
measured with the following: 

Measurement distance (h) : 5 m 
Radius of phase conductor : 0.007727 m 
Permittivity of air (𝜋𝜋0 ) : 1 
Permittivity of insulation (𝜋𝜋𝑟𝑟) : 4.5 

The difference of permittivity will affect the 
magnitude of discrete charges around the area of 
measurement. Since the permittivity of air (𝜋𝜋0 ) is 
less than the relative permittivity of the insulator 
(𝜋𝜋𝑟𝑟 ), the breakdown voltage will be greater. So 
that the electric field around the wire conductor 
will be larger than the electric field around the 
transformator. Because there is some n charge in 
the system, then all the electric field of the 
system is calculated by equation (11). 

Figure 6 is a flow chart, and the results of 
charge discretization on transformator will be the 
calculation of the electric field from all sides. 
From Figure 7 can be explained as follows: 

 
a. Coordinates (x, y) of front view: 

x = (-1.25, 0, 1.25, -1.25, 0, 1.25, -1.25, 0, 
1.25, 1.25, 2.5, 0, -2.5, -1.25). 

y = (5, 5, 5, 5.75, 5.75, 5.75, 6.5, 6.5, 6.5, 7, 
7, 7.35, 7.75, 7.75) 

b. Coordinates (x, y) of 150 kV side: 
x = (-0.5, 0, 0.5, -0.5, 0, 0.5, -0.5, 0, 0.5, -

0.5, 0, 0.5) 
y = (5, 5, 5, 5.75, 5.75, 5.75, 6.5, 6.5, 6.5, 

7.75, 7.75, 7.75) 
c. Coordinates (x, y) of 20 kV side: 

x = (-0.5, 0, 0.5, -0.5, 0, 0.5, -0.5, 0, 0.5, -
0.5, 0, 0.5) 

y = (5, 5, 5, 5.75, 5.75, 5.75, 6.5, 6.5, 6.5, 7, 
7, 7) 

d. Coordinates (x, y) of above view: 
x = (-2.5, -1.25, 0, 1.25, 2.5, -2.5, -1.25, 0, 

1.25, 2.5, -2.5, -1.25, 0, 1.25, 2.5). 
y = (5, 5, 5, 5, 5, 5.5, 5.5, 5.5, 5.5, 5.5, 6, 6, 

6, 6, 6) 
 

Coordinates of measurement point for all view 
measurement located at the point P (0,0). 

 
 

Figure 6. Flow chart of CSM 
 

 Start

Plot the field distributions

End

N

Y

Input
boundary conditions,

parameters, and
dimension

Assume the possitions
of simulated charges
and matching points

Compute the
coefficient matrix

[Q] = [P]   [V]-1

Solve the
simultaneous

equations

Is the result reliable ?

 
 
Figure7. Coordinates of fictitious charge (a) front view, 
(b) 150 kV-side, (c) 20 kV-side, (d) above view 
 
 



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 

 

38 

IV. RESULTS AND DISCUSSIONS 
The simulation has been done using the Mat 

lab, the distribution of the electric field and 
equipotential lines from each side of the 
transformator three-phase 100 MVA, 150/20 kV 
at a distance of 5 meters measurements are 
shown in Figure 8 and Figure 9. 

Electric field distribution shown is the electric 
field strength, without indicating its direction, 
which is the vector sum of real and imaginary 
electric field in the direction x (horizontal) and y 
(vertical).  

The electric field generated from the front 
view of transformator has a maximum value at a 
distance of -2.6 m from the x-axis measurement 
point, with magnitude of electric field strength 
6833 V/m, respectively. While at the 
measurement point (5 m), the resulting electric 
field is higher than WHO standard, amounting to 
5541 V/m. According to equation (1), the farther 
the distance from the maximum value (x < -2.6 m 
and x > -2.6 m), the smaller the distribution of 
electric field is. 

The electric field generated from 150 kV-side 
of transformator has a maximum value at a 
distance of -3 m and 3 m from the x-axis 
measurement point, with magnitude of electric 
field strength, 3050 V/m (shown in Figure 10 and 
Figure 11). While at the measurement point, the 
resulting electric field is smaller than WHO 
standard, amounting to 1930 V/m. The farther the 
distance from the maximum value (x < -3 m and 
x > 3 m), the smaller the distribution of electric 
field is. 

The electric field generated from 20 kV-side 
of transformator has a maximum value at a 
distance of -3 m and 3 m from the x-axis 
measurement point, with magnitude of electric 
field strength 502 V/m, respectively (shown in 
Figure 12 and Figure 13). Mean while, at the 
measurement point (5 m), the resulted electric 
field is smaller at the amount of 427 V/m. The 
farther the distance from the maximum value (x < 
-3 m and x > 3 m), the smaller the distribution of 
electric field. 

The electric field generated from above of 
transformator has a maximum value at a distance 

 
 

Figure 10. Simulated and measured electric field of 
150kV-side 
 
 

 
 

Figure 11. Equipotential distribution of 150 kV-side 
 
 

 
 

Figure 8. Simulated and measured electric field in front 
viewof power transformator 

 

 
 

Figure 9. Equipotential distribution in front view of 
power transformator 
 



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 
 

 

39 

of -0.5 m from the x-axis measurement point, 
with magnitude of electric field strength 9960 
V/m, respectively (shown in Figure 14 and 
Figure 15). While at the measurement point, the 
resulting electric field is smaller, in the amount of 
9890 V/m. The farther the distance from the 
maximum value (x < -0.5 m and x > 0.5 m), the 
smaller the distribution of electric field is. 

From all measurement results, the electric 
field around the wire conductor (R, S, T) without 
isolation is greater than the electric field around 
an isolated transformator wall, this is due to 
differences in the dielectric permittivity (𝜋𝜋) of a 
medium that causes the breakdown voltage 
differences that affect the magnitude of the 
electric field generated. 

The level of precision and measurement error 
in the simulation results depend on the 
determination of the location of the position 
discretization contour points to be measured as 
well as the boundary conditions as an important 
parameter in measuring and mapping the electric 
field. 

V. CONCLUSION 
From the simulation results of the electric 

field in the area of the transformator, it can be 
concluded that simulation results shows the 
magnitude of the electric field generated in power 
transformator at the measurement point (5 m) is 
5541 V/m. This can be considered that the safety 
limit of the electric field effect is in accordance 
with the WHO (World Health Organization), 
which is 5 kV/m. Moreover, CSM is efficient for 
calculating the electric field with fairly simple 
programs and less computing time. The surface 
of the electrodes and the polarization charges on 
the interface of different dielectrics are replaced 
by a set of discrete simulated charge. The types 
and positions of the simulated charges are 
predetermined. The magnitudes of these 
equivalent charges are determined by the 
boundary conditions on the collocation points of 
the boundary. Hence, CSM is one of the 
collocation methods and can be classified as an 
equivalent source method. 

 

 

 
 

Figure 12. Simulated and measured electric field of 
20kV-side 
 

 
 

Figure 13. Equipotential distribution of 20kV-side 
 
 
 

 

 
 

Figure 14. Simulated and measured electric field from 
above of power transformator 

 

 
 

Figure 15. Equipotential distribution from above of 
power transformator 

 



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 

 

40 

REFERENCES 
[1] D. M. Petković, et al., "The Effect of 

Electric Field on Humans in the 
Immediate Vicinity of 110 kV Power 
Lines," Facta Universitatis Series: 
Working and Living Environmental 
Protection, vol. 3, pp. 63-72, 2006. 

[2] N. Wertheimer and E. Leeper, "Electrical 
Wiring Configurations and Childhood 
Cancer," American Journal of 
Epidemiology, vol. 109, pp. 273-284, 
1979. 

[3] V. P. Korobkova, "Influence of the 
Electric Field in 500 and 750 kV 
Switchyards on Maintenance Staff and 
Means for Its Protection," in The 
International Conference on Large High 
Tension Systems, Paris, 1972. 

[4] S. Azmi, "Penggunaan FEM (Finite 
Elemen Method) dalam Memetakan 
Medan Listrik pada Permukaan Isolator 
Jenis PIN dan Post 20 kV dan Saluran 
Udara Sekitarnya," Jurusan Elektro 
Fakultas Teknik, Universitas 
Diponegoro, Semarang, 2011. 

[5] A. Risdiyanto, et al., "Effect of Contact 
Pressure on the Resistance Contact Value 
and Temperature Changes in Copper 
Busbar Connection," Mechatronics, 
Electrical Power, and Vehicular 
Technology, vol. 03, pp. 73-80, 2012. 

[6] S. N. Indonesia, "Ruang bebas dan jarak 
bebas minimum pada Saluran Udara 
Tegangan Tinggi (SUTT) dan Saluran 
Udara Tegangan Ekstra Tinggi 

(SUTET)," ed. Jakarta: Badan 
Standarisasi Nasional, 2002. 

[7] William H. Hayt, Jr., Ed., Engineering 
Electromagnetics. McGraw-Hill 
International Book Company, 1989. 

[8] M. F. Iskander, Ed., Electromagnetic 
Fields and Waves. Illinois: Waveland 
Press, 1992. 

[9] S. Salama, et al., "Comparing Charge 
and Current Simulation Method with 
Boundary Element Method for 
Grounding System Calculations in Case 
of Multi-Layer Soil," International 
Journal of Electrical & Computer 
Sciences, vol. 12, pp. 17-24, August 
2012. 

[10] A. Ranković and M. S. Savić, 
"Generalized charge simulation method 
for the calculation of the electric field in 
high voltage substations," Electrical 
Engineering, vol. 92, pp. 69-77, 2010. 

[11] N. H. Malik, "A review of charge 
simulation method and its application," 
IEEE Transaction on Electrical 
Insulation, vol. 24, pp. 3-20, 1989. 

[12] L. C. Shen and J. A. Kong, Aplikasi 
Elektromagnetik, 3 ed. vol. 2. Jakarta: 
Erlangga, 2001. 

[13] Y. Kato, "A Charge Simulation Method 
for the Calculation of Two-Dimensional 
Electrostatic Fields," Fukui University of 
Technology Bulletin, vol. 03, 1980. 

 
 

 



N.A. Rachman et al./ Mechatronics, Electrical Power, and Vehicular Technology 04 (2013) 33-40 
 

 

41 

 


	Introduction
	Basic Theory
	Electric Field
	Charge Simulation Method (CSM)
	Two Dimensional Charge Field
	Application of (CSM) for the Computation of the Electric Field in Power Transformator

	Methodology
	Specification of Measurement
	Boundary Conditions

	Results and Discussions
	Conclusion