Study of the Effectiveness of Lightning Protection System on 1 MWp

Bangli Solar Power Plant

I B. K. Sugirinta, I G. N. A. Dwijaya Saputra, I N. Mudiana and Ketut Ta

Department of Electrical Engineering, Politeknik Negeri Bali, Kampus Bukit Jimbaran, Bali, Indonesia

Keywords: Early Streamer Emission, Lightning Protection System, Solar Power Plant, Franklin Rod.

Abstract: Protection against the danger of lightning strikes is a crucial thing to consider for a large-scale solar power

plant. In this paper, a study of Franklin rod type for lightning rods is carried out, installed at the height of 15

meters to protect solar power plants with a land area of 1.8 ha. Franklin rod type lightning rod has cone-

shaped protection with 112

protection used as the basis for studying the effectiveness of protection. This

research aim is to find area of existing protection and propose recommendations for a protection system

against lightning hazards using an early streamer emission (ESE) system with a radius-shaped protection

system. Using an ESE radius of 150 meters, a study of its effectiveness found that it propounds in protecting

the solar power plant in Bangli from the influence of lightning surges. this existing LPS is not enough to

protect all areas of the plan. For grounding system, it is recommended to install two electrodes with a length

of 3 meters and a diameter of 5/8 inch.

1 INTRODUCTION

Lightning Protection Systems (LPS) is an

indispensable tool in protecting buildings and

electrical systems from the dangers of lightning

strikes. Lightning strikes also affect the solar module

(Moor, 1999), other equipment such as inverters

(Smith, 1998), and the operator. So it is crucial to

applies this LPS to the Bangli Solar Power Plant

(BSPP) located in Kayubihi Village, Bangli District,

Bangli Regency. This on-grid BSPL has no battery

and occupies 1.8 ha, where 80% of its area is for solar

module installation. There are 278 PV arrays, using

5005 monocrystalline solar modules with a maximum

power of 200 watts per module. Another part of the

BSPP is module buffers with a slope of 13-150, 50

units of inverter type SG20KTL with a capacity of 20

kVA, array protection panels, distribution panels,

step-up transformers, and lightning protection. BSPP

is always in an open area without being blocked by

trees and buildings so that solar radiation as a source

of BSPP energy can directly hit the surface of the

solar panels. With conditions like this, the existence

of BSPP, especially large-scale ones, is very

vulnerable to the danger of lightning strikes. As a

tropical country, Indonesia has a high evaporation

rate, with 200 lightning strikes per year per km2 or

the thunderstorm days or the number of or IKL (Iso

Crounic level). The magnitude of this IKL indicates

the possibility of losses incurred in each strike. In

BSPP, these losses can damage buildings, equipment

(solar panels, inverters) (Moore, 1999), data networks

and even threaten the lives of living things.

Some equipment such as inverters in BSPP has a

protection part for over or low voltage problems, anti-

islanding, overheating, and lightning protection. The

preliminary study found the damage of 30 units of

inverter due to a lightning problem. There is only a

conventional lightning rod with a Rods system or rod-

type by placing a lightning receiving conductor rod in

a tower covering the entire BSPP area, which is quite

Figure 1: Layout of the Solar Energy Plant.

650

Sugirinta, I., Saputra, I., Mudiana, I. and Ta, K.

Study of the Effectiveness of Lightning Protection System on 1 MWp Bangli Solar Power Plant.

DOI: 10.5220/0010950500003260

In Proceedings of the 4th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2021), pages 650-656

ISBN: 978-989-758-615-6; ISSN: 2975-8246

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

large. The damage to the inverter, solar module, and

the installation in this plant might be due to the

condition of external lightning protection, so it is

necessary to evaluate the effectiveness of the existing

LPS in BSPP.

2 LIGHTNING PROTECTION

SYSTEM

2.1 Lightning Strikes Problems

Lightning strikes can cause damage and result in a

loss effect for objects, including:

2.2.1 Direct Lightning Strike against

Buildings

Lightning strikes directly hit the structure of houses,

offices, and facilities. This lightning is very

dangerous for the construction and its contents

because it may cause fire, damage to electrical/

electronic devices, or even fatalities. Therefore, every

building is required to install a lightning rod

installation. The way to handle it is by installing a

lightning strike receiving terminal and other

supporting facilities following predetermined

standards. Moreover, if a lightning strike directly hits

a human, it can result in injury or disability and even

cause death. There are so many incidents of direct

lightning strikes that hit humans and usually occur in

open areas.

2.2.2 Lightning Strikes through the

Electricity Network

The danger of this strike is when it hits something

outside the building area but impacts the electricity

network inside the building. The electrical system's

striking effect occurs when the electricity distribution

network system uses open-air cables located at a high

place. If lightning strikes this open cable, the high

current will flow to consumer devices directly. The

way to handle it is by installing an arrester device as

an overvoltage safety device. The installation of this

electric surge arrester must be connected to a

grounding system.

2.2.3 Strikethrough Telecommunication

Network

The danger of this type of lightning strike is almost

the same as the second one but impacts

telecommunications equipment, such as telephones

and PABX. Installing a special arrester for the PABX

network with a grounding system can eliminate the

lightning strike. If the building to be protected has an

internet network via a telephone network, this tool

can also preserve the internet network.

2.2 Effects of Lightning Strike

Lightning strikes can cause various effects on the

struck object, namely:

a. Electric Effect

When a lightning current passes through a conductor)

to the resistance of the earth electrode of a lightning

rod installation, it will cause a resistive voltage drop,

which can immediately increase the voltage of the

protection system to a high value compared to the

earth voltage. This lightning current also creates a

high voltage gradient around the electrode's earth,

which is very dangerous for living things. Applying

the inductance of the protection system can reduce the

steepness of the lightning pulse waveform. Thus, the

voltage drop in the lightning protection system is the

arithmetic sum of the resistive and inductive voltage

components.

Translucent – Side Effects

Lightning strike points in lightning protection

systems can have higher voltages against nearby

metallic elements. Therefore, there will be a risk of

breakdown voltage from the lightning protection

system that has been installed to other metal

structures. If this breakdown voltage occurs, some of

the lightning currents will propagate through the

internal parts of metal structures such as iron pipes

and wires. This breakdown voltage can cause a

hazardous risk for the contents and framework of the

building structure to be protected.

c. Thermal Effects

In the case of lightning protection systems, the

thermal effect of a lightning discharge is limited to

the rise of the conductor's temperature through which

the lightning current passes. Although the current is

large quickly, its impact on the lightning protection

system is usually negligible. In general, the cross-

sectional area of the lightning rod installation

conductor is chosen primarily to meet the mechanical

quality requirements, which means it is large enough

to limit the temperature rise to 1 degree Celsius.

d. Mechanical Effects

If the lightning current passes through the parallel

supply cable (conductors) that are close together or on

Study of the Effectiveness of Lightning Protection System on 1 MWp Bangli Solar Power Plant

651

a conductor with a sharp bend will cause a large

enough mechanical force. Therefore, a sufficiently

mechanical solid bond is required. Another

mechanical effect of a lightning strike is caused by a

sudden rise in air temperature to 30,000 K and

causing an explosive expansion of air around the

moving charge path. This effect is because if the

conductivity of an electric arc replaces the

conductivity of the metal, the energy generated will

increase hundreds of times, and this energy can cause

damage to the protected building structure.

e. Fire Effect Due to Direct Strike

There are two leading causes of flammable material

fires due to lightning strikes, firstly due to direct

strikes on flammable materials storage facilities.

These volatile materials may be directly affected by

the heating effect of the lightning strike or the path of

the lightning strike. Both secondary effects are the

cause of oil fires. It consists of confined charges,

electrostatic and electromagnetic pulses, and ground

currents.

f. Stuck Load Effects

The cloud storm induces this static charge as opposed

to other loading processes. Suppose the charge

neutralization process ends and the strike path is

neutral again. In that case, the trapped charge will be

left on objects isolated from direct electrical contact

with the earth and on non-conducting materials such

as combustible materials. Non-conducting materials

cannot transfer charge in a short time when there is a

path of strike.

2.3 Lightning Protection System

2.3.1 External LPS

External Lightning Protection System avoids the

direct danger of a lightning strike in installations,

equipment installed outside the building, in towers,

and exterior parts of the building. This type of

protection includes the protection of people outside

the building. The External Lightning Protection

System consists of:

2.3.2 Air Termination

Air termination is part of an external lightning

protection system devoted to capturing lightning

strikes in metal electrodes mounted vertically or

horizontally. Terminal air is an area or zone that is

specifically for capturing lightning at a certain radius.

Lightning arresters can catch all lightning strikes

without hitting the building, building, or protected

area (protection zone).

2.3.3 Lightning Current Conductor (Down

Conductor)

The down conductor distributes lightning current that

hits the air termination (air terminal) and is forwarded

to earth/grounding (Smith, 1998 and Mendez, 2014).

The choice of the number and position of the supply

conductors should consider the fact that, if the

lightning current is divided into several supply

conductors, the risk of side-stepping and

electromagnetic interference within the building

should be considered is reduced. Based on the 2014

SNI 7015 standard that each down conductor installed

on a down conductor is installed on the shortest

possible route and does not cause a side-flash hazard

to humans/equipment and induction hazards,

especially for sensitive equipment. Down conductors

in installations with sensitive equipment must be

equipped with a lightning strike monitoring device

and a current recording device. Designing the down

conductors with small resistance is essential to direct

the lightning current to the ground.

In the ATP/EMTP software, the down conductor

has a replacement circuit that is a component of

resistance and inductance. Down conductor models

are generally modeled in terms of resistance and

inductance connected in series. The magnitude of the

resistance value in the down conductor can be

calculated using the following equation. Meanwhile,

to calculate the radius of the conductor using equation

(1)

2.3.4 Earthing (Grounding)

Grounding is planting one/several electrodes into the

ground in a certain way to get the desired grounding

resistance (Zaini, 2016). The grounding electrode

makes direct contact with the earth. A non-insulated

earth conductor embedded in the earth is considered

part of the earth electrode.

2.3.5 Internal IDIC

Implementing the concept of an internal lightning rod

is an effort to avoid potential differences at all points

in installing protected equipment inside the building

(Smith, 1998; Moore, 1999; Jiang, 2013; Zaini, 2016;

Mendez, 2016).

The steps that can be taken are integrating

potential equalizer facilities, installing voltage and

current arrestors, shielding, and filters. The

investment costs required for the procurement of

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

652

internal lightning rods are considerable. These costs

due to various mechanisms can cause potential

differences in the protected equipment, which can be

in the form of overvoltage propagation through the

line, telephone, antenna, electric power supply,

grounding, and various electromagnetic induction.

Some efforts to minimize costs are by defining the

zoning area of protection and reducing to a minimum

all lightning impulse currents or voltages that

propagate into buildings and installations. This

method reduces the risk of internal damage in

electrical equipment such as over-voltage and

induced voltage which is detrimental to the

equipment. Experience shows that maximum effort in

improving external lightning rods and applying to

shield can reduce the cost of internal lightning rods.

Specifically for the procurement of lightning

protection systems for explosive installations, three

main things must be considered as follows:

a. Aspects of external influence, which is the aspect

of the occurrence of lightning strikes. Security

measures must be taken care of to prevent electric

arc sparks, near the roof of the building, inside the

protected building, and in the grounding system.

The method that can be applied is to justify the

finial arrangement, distribution of lightning

current and grounding, and its connection and

prevent the "Faraday Hole" mechanism.

b. The operational aspect, which involves the

problem of a mixture of gaseous materials,

dramatically determines the temperature, voltage,

and ignition energy.

c. Internal Capability Aspect, which is an effort to

improve the installation's internal capability and

can eliminate the consequences that occur if it

turns out that there is a failure from the efforts of

the two aspects above.

3 DISCUSSIONS

3.1 Existing Condition

There is a conventional type LPS installed in Bangli

Solar Power Plant on top of an iron tower with a

height of 17.335 mm to protect the BSPP area of 1.8

ha.

3.1.1 Air Terminal

The installed type of LPS air terminal/receiver is

franklin rod type. The franklin type LPS can protect

the form of an inverted cone (dome), with a maximum

protection angle of 112

. For a protection angle of

112, the protective area will be in a radius of 2 x tan

112

, which is 25,700 mm. While the farthest distance

from the LPS to the PV position is 199.382 mm,

meaning that only 13% of the area is protected.

3.1.2 Down Conductor

The down conductor used is 50 mm

BC wire tied

along with the LPS tower and then planted at a depth

of 50 cm in the ground, stretched for 12 meters. Then

the ends are connected to grounding rods.

3.1.3 Grounding

There is no ground rod for thiss PLS the grounding

system uses a bare conductor (BC) that is planted at a

distance of 8 meters from the LPS tower. Total of the

length of the BC is 10 meters under ground. The result

of the measurement of the grounding value (earth) is

5.6 Ohms. This value is greater than the specified

minimum standard of 5 Ohms.

3.2 System Redesign

By looking at the condition of the existing LPS,

which is not effective in providing comprehensive

protection for BSPP, it is necessary to re-plan the

existing LPS to provide more effective protection for

the entire BSPP area.

3.2.1 Determination of Protection Level

The selection of the level of protection aims to reduce

the risk of damage, below the maximum tolerance

level, by a direct lightning strike to the building or

space being protected.

3.2.2 Lightning Strike Density (Ng)

Lightning strike density is calculated by equation-(1)

𝑁𝑔 = 0,04𝑥𝑇𝑑

,

(1)

where

Td = average number of lightning annually for Bali

= 61, so:

Ng = 0,04x61

1,26

= 7,105

3.2.3 Frequency of Strikes

The calculation of the frequency of lightning strikes

(Nd) uses equation (2).

Nd = Ng x Ae x 10

-6

(2)

Study of the Effectiveness of Lightning Protection System on 1 MWp Bangli Solar Power Plant

653

Where Ae is the protection coverage area (m2), which

is calculated by equation (3)

Ae = ab + 6h (a + b) + 9 π h

(3)

Where,

a = length of protected area (260 m)

b = width of protected area (137 m)

h = building height (5 meters)

So that the area of protection coverage is obtained

with the following calculations:

Ae = 260.137 + 65 (260 + 137) + 9 (3.14) (5)

= 135,843 m2

So the strike frequency (Nd) can be calculated as

follows:

Nd = 7,105 x135,843 x 10

-6

= 0.965 strikes / km2/year

3.2.4 Protection System Requirements

Determination of protection needs is determined

based on the calculation of the lightning strike

frequency (Nd) and the permissible lightning strike

frequency (Nc) regarding the following conditions:

a. If Nd Nc, there is no need for a lightning

protection system.

b. If Nd Nc, a lightning protection system is

required.

The allowable local annual lightning strike

frequency (Nc) is 10-1, while Nd = 0.965, then Nd is

greater than Nc, so a protection system is needed.

3.2.5 Lightning Strike Efficiency

With the need for a protection system, it is necessary

to calculate the efficiency of the system that needs to

be installed properly using equation (4):

E ≥1 –





(4)

≥ 1 -

,

,

≥ 0,896 (89,6%)

The system's efficiency is 89,6%, and it is at level III

of the protection level.

Table 1: Protection level and their efficiency.

Protection

level

Efisiensi

LPS

I 0,98

II 0,95

III 0,90

IV 0,80

(SNI 03-7015-2004)

3.2.6 Determination of Air Terminal and

Location

The Bangli solar plan requires an LPS with level III

protection. Considering that there is not much need

for a lightning protection system, as an alternative,

the Early streamer emission (ESE) type LPS is

chosen, which has radius type protection. By knowing

the outside of the protection area calculated above,

which is 135,843 m

, the required LPS radius can be

calculated using equation (5) that is denoted as

follows:

𝐴=𝜋𝑟



(5)

135.842 = 3,14 . r

r = 210 m

Figure 2: Area of protection of 2 LPS R100.

3.2.7 Down Conductor

LPS with a radius of 210 meters are not available in

the market. As an alternative, two LPS with r = 100

meters are chosen with the placements shown in

Figure 2. LPS-1 is placed at the Existing LPS position

while LPS-2 is placed at the far right of the area.

Figure 2 shows that two radius type of LPS protects

the entire BSPP area with r is 100 meters. The

installation height is 15 meters, the same as the

existing condition.

3.2.8 Grounding Electrode

The LPS grounding resistance value at BSPP is

designed to have a maximum value of 4 ohms, with

the following conditions:

1) embedded BCC length is 10 meters

2) The length of the electrode is 3 meters

3) electrode radius is 0.0079375 meters (D 5/8

inch = 0.015875 m)

4) ground resistance is 100 ohm.m

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654

The value of the grounding resistance calculation uses

equation (6).



  

. (𝑙𝑛





−1) (6)

Where

ρ : earth resistance (100 ohm/m )

l : length of grounding electrode (3m + 10m)

α : radius of grounding electrode (0,0079375 m)

The calculation result is:



.,.()

. (𝑙𝑛.

.()

,

−1)

= 8 ohm

It is known that the Bangli PLTS requires an LPS

with level III protection. Considering that there is not

much need for a lightning protection system, as an

alternative, the Early streamer emission (ESE) type

LPS is chosen, which has radius type protection. By

knowing the outside of the protection area calculated

above, which is 135,843 m

, the required LPS radius

can be calculated using equation (7). By using this

equation, a number of electrodes can be found.

𝑅𝑛 =





𝑥 𝐹 (7)

where

Rn : resistansi parallel sn (ohm )

n : number of resistors in parallel

F : multiply factor

so:

𝑛

𝑥 1

n = 2

So, it recommends installing two electrodes with a

length of 3 meters and a diameter of 5/8 inch.

These two electrodes are installed in parallel, so the

resistance value becomes 4 ohms.

3.3 Comparison Results

Table 2 shows the comparation between existing PLS

and the proposed one. Number of air terminal is

doubled to protect all area or 100% area protection.

The down conductors for these conditions are

BC 50 mm

but the length of the proposed PLS is 2m

shorted.

In existing PLS there is no ground rod, but 2

ground rods are needed for proposed system with 3 m

length and 5/8 inches diameter. The earth resistance

value for the new proposed PLS is less than the

existing ones and meet to the standard value.

Table 2: Existing vs Proposed PLS.

No Item Existin

Pro

osed

1Air Terminal

type Franklin ro

ESE

numbe

1 2

max angle 112

radius 25.7

100 m each

area

rotection

40.349 m

2 x 135.842 m

% area 13% 100%

hei

h 15

2 Down Conductor

type BC 50 mm

BC 50 mm

len

th 12

depth 50 c

50 c

3 Grounding

round ro

- 2

earth

resistant

6 Ohms 4 Ohms

length - 3

diamete

- 5/8 inch

4 CONCLUSIONS

This study of the effectiveness of the lightning

protection at Solar plan Bangli found that the existing

protection uses a Franklin rod type for its air terminal

with 15m high. It only has a 13% protection area. In

addition, the measurement of the grounding system of

this LPS is 5.6 ohm, or it does not meet the standard

value of ground resistance. So, this existing LPS is

not enough to protect all areas of the plan. It is

recommended to install two electrodes with a length

of 3 meters and a diameter of 5/8 inch.

ACKNOWLEDGEMENTS

The author thanks the Center of Research and

Community Service Polteknik Negeri Bali.

REFERENCES

Araneo, R., Maccioni, M., Lauria, S., Celozzi, S. (2017).

Analysis of the lightning transient response of the

earthing system of large-scale ground-mounted PV

plants. IEEE Manchester PowerTech, Manchester. pp.

1-6. doi: 10.1109/PTC.2017.7981087.

Baba., Y., Rakov, V.A. (2014). Applications of the FDTD

Method to Lightning Electromagnetic Pulse and Surge

Simulations. in IEEE Transactions on Electromagnetic

Study of the Effectiveness of Lightning Protection System on 1 MWp Bangli Solar Power Plant

655

Compatibility, vol. 56, no. 6, pp. 1506-1521. doi:

10.1109/TEMC.2014.2331323.

Charalambous, C., A., Kokkinos, N., D., and N.

Christofides, N., (2014). External Lightning Protection

and Grounding in Large-Scale Photovoltaic

Applications. in IEEE Transactions on

Electromagnetic Compatibility., vol. 56, no. 2, pp. 427-

434. doi: 10.1109/TEMC.2013.2280027.

HernÁndez, J. C., Vidal, P. G., and Jurado, F. (2008).

Lightning and Surge Protection in Photovoltaic

Installations. in IEEE Transactions on Power Delivery,

vol. 23, no. 4, pp. 1961-1971. doi: 10.1109/TPWRD.20

08.917886.

IEC (2010). IEC Protection against lightning - Part 2: Risk

management. Standard 62305-2 Ed. 2.0.

IEC (2010). IEC Protection against lightning - Part 1:

General principles. IEC Standard 62305-1 Ed. 2.0.

Jiang, T., Grzybowski, S. (2013). Impact of lightning

impulse voltage on polycrystalline silicon photovoltaic

modules. International Symposium on Lightning

Protection (XII SIPDA), Belo Horizonte, Brazil. pp.

287-290. doi: 10.1109/SIPDA.2013.6729225.

Kokkinos, N., Christofides, N., C. Charalambus, C.,

Lightning Protection Practice for Large -Extended

Photovoltaic In stallat ions. International Conference

on Lightning Protection (ICLP), Vienna, Austria.

Mendez, H.Y., Ioannidis, D., Ferlas, G., E. Giannelaki. T.,

Politis, Z., and Samaras, K. (2014). An Experimental

Approach of the Transient Effects of Lightning

Currents on the Overvoltage Protection System in MW

-Class Photovoltaic Plants. International Conference

on Lightning Protection (ICLP), Shanghai, China. pp.

1972-1977.

Méndez, Y., Acosta, i., Rodriguez, J., C., Ramírez, J.,

Bermúdez and Martínez. M. (2016). Effects of the PV-

generator's terminals connection to ground on

electromagnetic transients caused by lightning in utility

scale PV-plants. 33rd International Conference on

Lightning Protection (ICLP), Estoril, Portugal. pp. 1-

8. doi: 10.1109/ICLP.2016.7791382.

Moore, R., Lopes, J. (1999). Paper templates. In

TEMPLATE’06, 1st International Conference on

Template Production. SCITEPRESS.

Pons., E., Tommasini, R. (2013). Lightning protection of

PV systems. 4th International Youth Conference on

Energy (IYCE), Siófok, Hungary, pp. 1-5. doi:

10.1109/IYCE.2013.6604209

Sakai, K., Yamamoto, K., (2013). Lightning protection of

photovoltaic power generation system: Influence of

grounding systems on overvoltages appearing on DC

wirings. International Symposium on Lightning

Protection (XII SIPDA), Belo Horizonte, Brazil. pp.

335-339. doi: 10.1109/SIPDA.2013.6729211.

Smith, J. (1998). The book, The publishing company.

London, 2

edition.

Tan, P. H., Gan, C. K. (2013). Methods of lightning

protection for the PV power plant. IEEE Student

Conference on Research and Developement, Putrajaya,

Malaysia. pp. 221-226, doi: 10.1109/SCOReD.20

13.7002575

Zaini, N.H., et al. (2016). On the effect of lightning on a

solar photovoltaic system. 33rd International

Conference on Lightning Protection (ICLP), Estoril,

Portugal. p. 1-4. doi: 10.1109/ICLP.2016.7791421.

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