1st Conference of Industrial Technology ( CIT2017)

Analyzing and Modeling the Separation Distance

of Lightning Arresters For A 400KV Substation
Protection Against the Lightning Strokes
Adel Salem Sultan
Electrical and Computer Engineering Department, Engineering Faculty, AL-Mergib University
AL-Khoms, Libya
aadelsultan@gmail.com

Abstract –The aim of this paper is to study the effect of measures for protecting power network equipment. The
separation distance of lightning arresters to protect the modeling transient behavior of a tower is very important
400KV substation against the direct lightning strikes. Hence at time of lightning and for a transmission line which has
this study, the performed analysis for assessing single phase been designed well, direct collision of lightning with
ignition and back flash over, The testing system consists of
four towers and a substation, The paper illustrates the
conductors of phases seldom occurs. Lightning causes
benefit of Alternative Transient Program / Electromagnetic many outages due to back flash over. When lightning
(ATP / EMTP) to finding the best type of arrester against collides with shield wire or tower, the injected current on
the lightning. This circuit where exposed to the 260 KA tower to earth and causes an increase of voltage and this
lightning current after change the arrester separation issue causes back flash over [3].
distance at transformer from 5m to 30m. The results showed There are two approaches of overhead lines’ behavior
that if the increased separation distance at 15m for arrester at lightning strokes. Some analytical models determine
of the type (Zinc Oxide-porcelain EXLIM Q1) is going to the pulse voltages` time evolution, considering the
happen breakdown of the substation. Whereas find that if repeated reflections, even at the towers’ level [4,5], others
the increased distance from 5 to 30 m for arrester type (Zinc
Oxide-silicone polymer PEXLIM Q2) be a good transformer
analytical models asses, only in a quantitative way, the
protection, Also results of this study show that silicone lines` performance at lightning over voltages on basis on
polymer arrester is better and more acceptable than the specific number of outages indicator, These often used
porcelain arrester for the studied line. To avoid the problem models in estimation calculations operate with the
of transient waves change the transmission lines system voltages’ and currents’ peak values, having no interest for
protection and of which choosing good lightning arrester as their time evolution [6,7].
well as reduce the separation distance between the arrester The stress of the lines’ insulators is analyzed on basis
and transformer. on parameters like: towers’ surge impedance, pulse surge
impedance of the grounding grid, the electrostatic and
Index Terms— lighting currents, lightning arresters,
separation distance, ATP/EMTP, BIL insulation level.
electromagnetic induced voltages, the modification of the
coupling factors in presence of the corona discharge, the
I. INTRODUCTION polarity of the pulse and line’s span [8].
Exposed electrical network to traveling impulse waves, To design insulator of power systems, study of
as a result, the system voltage rises to very high values lightning behavior and overvoltage resulting from it is an
may ultimately lead to the destruction of one of the important factor in protection of different tools of
components of electrical network, For this reason it is substations and power plants. Lightning seldom directly
important to study the impact of these high voltages, And collides with a transmission line. Lightning almost
also methods the protection of them to improving the collides on top of tower of transmission line or shield
performance of the network under this circumstances, wires and lightning currents flow on top of tower
This traveling impulse waves produced from a number downward. This major current increases its voltage
of external factors such as the phenomenon of lightning considering impedance of the tower. With increase of
and the phenomenon of electrostatic friction that results tower voltage, ignition may be created between the arms
from sand storms. It produces waves of traveling also of the tower and earth and between two arms of the tower
from several internal factors such operations as closing [9,10].
and opening of the circuit breakers, or a sudden cutting There are several studies conducted on this subject of
for line the result of a faults incidence, all of these which: in [11]. Study the voltage of lightning strikes on a
problems have been hurt to the destruction of insulators number of transmission lines in the Libyan network
and substations, If there is no good protection for the (200kV, 400kV), It was the annual hangouts these lines
system [1,2]. rate calculation resulting from lightning strikes and using
On this basis, it is very important to identify the program ATP/EMTP, It was also hangouts rate is
phenomenon of lightning and calculate density of calculated by mathematical equations and comparing the
lightning in different regions in order to take necessary results of the program, In [12] it was given about the
phenomenon of lightning and it is effect on the electrical
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 1st Conference of Industrial Technology ( CIT2017)

network, after reaching the results showed a clear picture

of the importance of lightning arresters using the program
ATP / EMTP simulation of lightning strike hit the sub-
station and transmission line with no arrester again with
use.
In the present paper, the characteristics of the
Separation Distance of Lightning Arresters For A 400KV
Substation Protection Against the Lightning Strokes have
been presented based on lightning simulation with ATP /
EMTP with negative polarity. The paper is organized as
follows: in section II, the system model is presented. Two
different models of arrester including (Zinc Oxide-
porcelain EXLIM Q1) and (Zinc Oxide-silicone polymer
PEXLIM Q2) arrester are evaluated in section III. Result
of two models included in the paper is mentioned in
section IV and finally the most important results are
elaborated in section V.

II. SYSTEM MODEL

Figure 2. Tower configuration
This part introduces single line diagrams of the 400kV
network composed of four towers and the substation. The
400kv single circuit transmission line has triplet bundle Table 1. Conductor characteristics
conductors. Tower footing resistance of this system is 10
ohms, and the distance of the arrester at transformer Alph
Ph Rin Rout Rho Horiz Vtow Vmid
changes from 5 m to 30 m, and the range of lighting a No
current is 260 KA with negative peak and the following no
bun
Ω/km dl
figure 1. shows model for a 400 kV network using a cm cm
DC
m m m Deg
program ATP. The figure 2. Shows the structure of the
studied tower, Physical specifications of conductors and -
1 0 1.32 0.079 41.7 27.4 30 3
11.38
geometrical parameters of tower are given in tables 1 – 3
[13,14]. 2 0 1.32 0.079 0 42.7 28.4 30 3

3 0 1.32 0.079 11.38 41.7 27.4 30 3

Table 2. Ground wire characteristics

Ph Rin Rout Rho Horiz Vtow Vmid

no DC
Cm cm Ω/km m m m
4 0.48 0.87 0.3 -6.28 51.27 39.07

5 0.48 0.87 0.3 6.28 51.27 39.07

Table 3. Conductor arrangement of overhead transmission line

Number.ph Vertical Horizontal

1 41.7 m -11.38m
2 42.7 m 0
3 41.7 m 11.38m
Ground Vertical Horizontal
wire
Figure 1. Shows the structure of 400kv studied system 4 51.27 m 0m
5 51.27 m 0 m

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III. EVALUATION OF LIGHTNING ARRESTER.

Lightning arresters are devices used at substations and Table 5. Brief performance data for tow arresters
Zinc Oxide Zinc Oxide
at line terminations to discharge the lightning over Arrester type
EXLIM-Q1 PEXLIM-Q2
voltages and short duration switching surges. These are System voltage 170 -420 kv 52 - 420kv
usually mounted at the line end at the nearest point to the
substation. They have a flashover voltage power than that Rated voltage 132 -420 kv 42 - 360kv
of any other insulation or apparatus at the substation. Nominal 10 KA
10 KA
These are capable of discharging 10 to 20 kA of long discharge current
duration surges (8/20 µsec) and 100 to 300 kA of the Line discharge Class 3
short duration surge currents (1/5 µsec) [15]. Class 3
class
The following are the basic requirements of a Lightning
Short-circuit 65kA 50kA
Arrester:
Mechanical 18000Nm
2500Nm
i. It should not pass any current at normal or Strength
abnormal (normally 5% more than the normal Design altitude max 1000m max 1800m
voltage) power frequency voltage. Ambient -50 Cº to +45 Cº
ii. It should breakdown as quickly as possible after -50 Cº to +45 Cº
temperature
the abnormal high frequency voltage arrives.
Frequency 15 – 62 Hz 15 – 62 Hz
iii. It should interrupt the power frequency follow
current after the surge is discharged to ground.
In this paper will study two types of surge arresters. V. ATP ANALYSIS OF 400KV CIRUIT DIAGRAM
In this paper will study the resulting voltage from a
A. First arrester of type (Zinc Oxide EXLIM-Q1): blow by lightning current has a rang 260KA on ground
Protection of switchgears, transformers and other wire with changing the arrester separation distance at
equipment in high voltage systems against atmospheric transformer, which ranging between 5 m to 30 m, With
and switching overvoltages. using two types of arresters, In each case it will be
The design is based on successful experience of over 60 calculated extent the basic insulation level (BIL) of the
years, first as gapped arresters, in all climates and transformer and then shows the impact of the lightning on
conditions all over the world. EXLIM arresters live up to the transformer insulator.
their name: EXcellent voltage LIMiters. The design is
robust and well-matched with the other apparatus in A. First Case:
substations, It is made from Porcelain [16]. In this case, results of study are based on ATP / EMTP
software. lightning current has a range of 260 kilo
B. Second arrester of type (Zinc Oxide PEXLIM –Q2): amperes, with a changing of arrester separation distance
Protection of switchgear, transformers and other at the transformer from 5 m to 30 m, increase the distance
equipment in high voltage systems against atmospheric 5m in each step, by using the arrester of type (Zinc
and switching overvoltages. Oxide EXLIM-Q1)
PEXLIM arresters, using the same ZnO blocks as the
EXLIM arresters, match their electrical performance. Figures 3,4 Show the values of the internal voltages of
Silicone rubber as outer insulation material has been used the transformer on the primary side 400KV when
for over 25 years with good results and has been chosen distance 5m and 10m Respectively result of lightning
by ABB for arresters as well. It confers the additional current 260 kA by using (Zinc Oxide EXLIM – Q1).
benefits of low weight, improved pollution performance,
increased personnel safety and flexibility in erection, It is
made from silicone polymer [16,17].
Table 4. shows the arrester characteristics for the voltage
and current for tow arresters, and Table 5. Shows brief
performance data for tow arresters and .

Table 4. The relationship between voltage and current

Arrester type Zinc Oxide Zinc Oxide
EXLIM-Q1 PEXLIM-Q2
I(A) V1(v) V2(v)
1500 783000 654000
3000 821000 680000
5000 856000 737000
10000 914000 776000
20000 991000 854000
40000 1102000 954000
Figure 3. The inside voltage of the transformer when distance 5m

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 1st Conference of Industrial Technology ( CIT2017)

of lightning current 260KA

Figure 5 . The inside voltage of the transformer when distance 5m

of lightning current 260kA

Figure 4. The inside voltage of the transformer when distance 10m

of lightning current 260kA

Thus, it increase the arrester separation distance at the

transformer width by 5m and test the system. In each
step, it calculate the basic insulation level of the
transformer BIL using the following formula:

(1)

Where: (BIL) equal 1300kV [18-20].

(max overvoltage) Is the maximum voltage on the
primary side 400kV for transformer.
To be a good insulation level for transformer in front Figure 6. The inside voltage of the transformer when distance 10m
of lightning current 260KA
of the lightning wave must be this ratio does not less than
20%, If this ratio was less than 20% will result in Thus, it increase the arrester separation distance of the
destructive damage for entire transformer [19-22]. transformer width by 5m and test the system. In each
case, it calculate the basic insulation level of the
-When be arrester separation distance at the transformer transformer BIL using the last law.
is 5m be BIL: The table 6. and the figure 7. show the change extent
Then: of insulation level (BIL) for the transformer by 260kA
lightning current on the primary side 400Kv of the
transformer when arrester distance ranging from 5m to
30m for both two types of surge arresters
the rest of results have been listed in the table 6.
Table 6. Effect of the arrester distance on inside voltage
B. Second Case : of transformer when be 260KA lightning current.
In this case will study the resulting voltage from a
stroke by lightning current has a rang 260 kilo amperes Zinc Oxide EXLIM Zinc Oxide PEXLIM
Distance – Q1 – Q2
with a changing of arrester separation distance at the m Overvoltage BIL Overvoltage BIL
transformer from 5 m to 30 m, increase the distance 5m kV % (kV) %
in each step, using the arresters (Zinc Oxide PEXLIM-
Q2). 5 894.17 45.23% 824.66 57.64%
Figures 5,6 Show the values of the internal voltages of
the transformer on the primary side 400kV when distance 874.29
10 994.88 30.66% 48.69%
5m, 10m Respectively result of lightning current 260 kA 904.08
by using (Zinc Oxide PEXLIM –Q2). 15 1054.8 23.24% 43.79%
927.47
20 1097.9 18.42% 40.16%

25 1112.2 16.88% 940.02

38.29%
30 1134.7 14.56% 955.08

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 1st Conference of Industrial Technology ( CIT2017)

36.11% effects and analysis” IEEE Transactions on Power Delivery, Vol.

18, pp. 545-550, April 2003.
[4] Dragan, G., Tehnica tensiunilor înalte –Volumul I, Editu-ra
Tehnica, Bucuresti, 1996.
[5] Mata, C., Fernande,z M., Rakov, V., Uman M: EMTP Modeling
of a Triggered-Lightning Strike to the Phase Conductor of an
Overhead Distribution Line, IEEE Transactions on Power
Delivery, vol. 15, no. 4, p`p. 1175-1181, 2000.
[6] *** Guide for improving the lightning performance of
transmission lines, IEEE standard 1243-1997.
[7] CIGRE WG 33-01, Guide to procedures for estimating the
lightning performance of transmission lines, October 1991.
[8] P.C.A. Mota, M.L.R. Chaves, J.R. Camacho, “ Power line tower
lightning surge impedance computation, a comparison of
analytical and finite element methods” In: ICREPQ’12
International Conference on Renewable Energies and Power
Quality, pp. 1-6, March 2012.
[9] J.W. Woo, J.S. Kwak, H.J. Ju, H.H. Lee, J.D. Moon, “The analysis
results of lightning over voltages by EMTP for lightning
protection design of 500 kV substation” In: IPST International
Conference on Power Systems Transients, pp. 1-5, June 2005.
[10] N. Nagaoka, “A development of frequency dependent tower
model” IEE Transactions on Japan, Vol. B-111, pp. 51–56, Jul
Figure 7. Effect of the arrester distance on inside voltage
1991.
of transformer when be 260KA lightning current. [11] E. Mohamed, "Analysis of traveling waves effected on the
overhead transmission lines", Master thesis, dept. electrical Eng,
VI. CONCLUSION the Libyan Academy, 2008.
[12] S. Ali, " Design of Lightning Arresters for Electrical Power
The purpose of this paper was to study the extent of the
Systems Protection" Advances in electrical and electronic
impact of arresters separation distance at transformer for engineering, Vol. 11, no. 6, pp. 433-442, 2013 .
protection against lightning strokes. Using the ATP [13] High voltage technical manual, Department of High voltage
program, the study reached a number of important control, The General Electrical Company of Libya, 2015.
[14] M. Abu aaisha, A. Alfelo, " Analyzing and Modeling the
conclusions :
Separation Distance of Lightning Arresters For A 400KV
Substation Protection Against the Lightning Strokes" , ", B. SC
 The results showed that when using arrester the type thesis, dept. electrical Eng, El-mergib University, 2016.
(Zinc Oxide EXLIM- Q1), and by using the [15] Naidu M.S & V, kamraju, "High Voltage Engineering", (second
Edition), McGraw-Hill puplishing company limited, 1995.
lightning current 260KA when be distance 15m and [16] Buyers Guide, "High Voltage Surge Arrester", ABB Power
less be BIL good, But when be distance 20m and Technology Products AB, Edition 2, 2002.
above will break down the insulation level of the [17] J. Woodworth, "Separation Distance for Substations", Arrester
transformer in front of the lightning wave destroying Works, Arrester Facts 024, September, 2014.
[18] E. Kuffel, W. Zaengl, J.Kuffel, "High Voltage engineering
transformer fundamentals", published by Butterworth-Heinemann, 2000.
 When using arrester the type (Zinc Oxide PEXLIM [19] J. Duncan Glover, M. Sarma, T. J. Overbye, "Power System
Q2) with distance ranging from 5m to 30m and by Analysis and Design," THOSON Publishing Company,
using the lightning current 260 KA it is good 2008.
protection for system. [20] H. Ryan, "High Voltage engineering and Testin", The Institution
of Electrical Engineers, London United Kingdom, 2001.
 Better value for the arrester distance at the
‫ بيروت دار الراتب‬،‫ "الموجات الراحلة علي نظم القوى والحماية منها‬،‫] محمد عالم‬12[
transformer helps protect the network from lightning .2994 ،"‫الجامعية‬
strikes are 5m and less. ‫ " دراسة تأثير مقاومة قدم البرج في‬،‫ هشام الشوماني‬،‫ حمزة كتيبي‬،‫] عادل سلطان‬11[
 Arrester of type (Zinc Oxide-Silicone Polymer ، "‫" للحماية من ضربات الصواعق‬220 kV" ‫مستوى عزل محوالت الجهد العالي‬
PEXLIM Q2) best insulation from arrester of type .1026 - )EEES( ‫الندوة العلمية األولى للهندسة الكهربائية واإللكترونات‬
(Zinc Oxide-Porcelain EXLIM Q1).
 Calculating the basic insulation level (BIL) of the
transformers shows the extent of the impact of
voltages rises duo to increasing the separation
distance of arresters at transformer.
 Occurs exit the substation if the value of BIL is less
than 20%.

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tower model for lightning surge over voltage analysis” In: PSC of
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[3] Ito, T. Ueda, T. Watanabe, H. Funabashi, T. Ametani, “A.
Lightning flashovers on 77-kV systems: observed voltage bias