Safe and Secure Shaft to Support Robotic Hand on Live Line

Operation

Ni Putu Susri Aprilian Iriani, I Wayan Jondra and I Nengah Sunaya

Electrical Department, Politeknik Negeri Bali, Jalan Kampus Bukit Jimbaran, Kabupaten Badung, Indonesia

Keywords: Safe, Live Line, Secure.

Abstract: The biggest problem that can affect the stability and reliability of the power system is a disturbance.

Disruption of the electric power system can be caused by two factors, namely internal (ex: Pin Insulator

rupture) and external factors (ex: animals). In particular moments outages may occur and cause by animals

such as birds, squirrels, and snakes. Reducing the outage requires periodic maintenance in order to overcome

such interference by installing Tekep Isolator. When first introduced Tekep Isolator was very effective to

overcome the momentary interruption / permanent caused by animals, but the job requires considerable time

and shut off the electric power. To cope with blackout feeders for the installation of the Tekep Isolator, then

made the tool post Tekep Isolator. The results of a comparative analysis of the installation work insulator caps

with and without blackout obtained significant savings. So, this tool is very useful if it is implemented in PT

PLN (Persero) Region Bali and other areas that use the same type of Tekep Isolator. The shaft's insulation

value is more than 100 Giga Ohm, the leakage current is lower than 1 milliampere, the dielectric strength is

more than 11.6 kV, and the worker distance to live parts is more than 60 cm to make the system a safe state.

1 INTRODUCTION

Electrical energy is one of the important factors in the

development of every nation, including Indonesia.

Electrical energy has an important role for

development in both economic and social aspects.

Currently in Indonesia the only distribution of

electrical energy is PT PLN (Persero). In the

distribution of electrical energy, it is expected that the

maximum power is channeled, so that consumers and

producers feel comfortable. The electrical energy

distribution system must have high reliability which

aims to maintain the quality and continuity of

electrical energy distribution (Fatmawati, 2021).

Reliability is a key word as a guarantee of the

continuity of electricity supply to customers. The

reliability performance in question is determined by

the low number of SAIFI (System Average

Interruption Frequency Index), SAIDI (System

Average Interruption Duration Index) and ENS

(Energy Not Sale) (Sumper et al., 2004). Based on

SPLN 59 of 1985, the permitted SAIFI is 1,199

times/year and the permitted SAIDI is 1.75

hours/year.

The Tekep Isolator is the brand of many insulator

cover, gives chance to PLN to overcome natural

disturbances in the all aluminum alloy conductor

shield (A3CS) network caused by trees, animals,

weather and so on. Tekep Isolator is a safety

component of the medium voltage air distribution line

(SUTM) network. The insulator tack is a component

that functions to protect the tensile insulator, prevent

fouling of the supported insulator, as well as to tie the

A3CS conductor to the supported insulator. Tekep

Isolator for substations can overcome phase-to-

ground faults (Fan et al., 2021). If a single phase to

ground fault occurs, it will interfere with the other

two healthy phases in a three phase system (Fan et al.,

2021)

In the installation of the insulator using a robotic

arm with on the live line work method it is chance to

reduce the value of SAIDI and SAIFI on the

performing distribution network maintenance and

providing the best service for customers. This paper

discusses the test result the shaft of the insulator

clamp installation tool with robotic hands for live line

work safety on A3CS cables in medium voltage

distribution.

Iriani, N., Jondra, I. and Sunaya, I.

Safe and Secure Shaft to Support Robotic Hand on Live Line Operation.

DOI: 10.5220/0011880400003575

In Proceedings of the 5th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2022), pages 781-786

ISBN: 978-989-758-619-4; ISSN: 2975-8246

781

2 RESEARCH METHODE

2.1 Research Approach and Concept

To analyze these problems, this study was designed

as a research with a qualitative approach. These

problems will be discussed from measurement and

test data, equipment calculations to obtain good

insulation for medium voltage work safety shaft, and

all connected components. This research was piloted

at PT. Adi Putra, and the test results were analyzed

statistically and mathematically to obtain the

feasibility of a 20kV shaft tool for electrical safety,

compare the role of electrical work safety, and then

draw conclusions and recommendations.

2.2 Total Sample

This research was conducted by tested one sample on

a shaft, tasted 6 data for each indicator. Data

collection was carried out by testing the wet and dry

conditions and measuring the value of the voltage and

leakage current flowing into the water rheostat

2.3 Variable Operational Definition

In testing the feasibility of this robot hand tool,

leakage current, insulation test, dielectric strength and

clearance were also observed. This test is carried out

by applying a voltage of 5,000 Volts and 10,000 Volts

to the head and handle terminals. The test voltage is

the amount of voltage applied to the sample through

a high voltage tester. Leakage current is the amount

of current flowing into the test sample, due to the

given test voltage. Dielectric distance and clearance

are measured with a ruler meter.

2.4 Data Analysis

Data obtained from the test results are processed

quantitatively. The data is processed mathematically

by the process of multiplication and division. The data

is also processed statistically by finding the smallest

value of all data if the limits are minimum such as

insulation resistance, dielectric strength, space

clearance, and finding the largest value of all data if the

maximum limit is such as in leakage. current condition.

3 RESULT AND DISCUSSION

The results of this study are illustrated by pictures and

tables. The analysis of the feasibility of the shaft as a

robot hand operation tool was carried out to ensure

work safety. Robotic hand tools must have good

insulating resistance and insulated shafts to ensure

work safety in construction, maintenance, repair and

upgrading of medium-voltage distribution. However,

no material is perfect, therefore research on this

feasibility test is very important. This 20kV shaft is

made of polypropylene pipe, which has good

electrical characteristics because its volume

resistivity coefficient is 8.5x10

Ohm-cm.

Figure 1: 20kV Shaft as robot hand operation tools.

The perfect insulating material has an infinite

resistance, which is currently not obtainable. There is

a small leakage current flowing in the insulating

material and it can be shown as below equation (Amin

& Amin, 2011).

V = I x R (1)

R = V / I (2)

where:

R = Insulating Resistance (Giga Ohm)

V = Voltage charge due the sample (Kilo Volt)

I = Leakage Current (microampere)

The normal air dielectric strength coefficient is 30

kV/cm, the total dielectric strength is total distance

multiple with dielectric strength coefficient, as shown

in the formula below (Kharal et al., 2018).

ℰ =ℰ

x d (3)

where:

ℰ = Dielectric strength (KV)

ℰ

= Dielectric strength coefficient (KV/cm)

d = distance (cm)

3.1 Result

The minimum insulation for medium voltage is 100

Mega Ohms (Post et al., 2020). The maximum

leakage current flow does not affect a shock to the

human body is 1 milli amperes (Saba et al., 2014).

Total the dielectric strength must exceed than the

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active voltage to avoid the electric discharge (Saba et

al., 2014). The minimum safe distance between

workers and 15,000 Volt active equipment is 90 cm

(Ghosh et al., 2015). This Insulation Resistance Test

is carried out to detect the quality of the 20kV shaft

insulation resistance. This test is carried out by

applying a voltage of 5,000 Volts and 10,000 Volts to

the head and handle terminals. The insulation

resistance test was carried out in dry and wet

conditions ten times, the wet condition test as shown

in figure 3.

Figure 2: Dry insulation resistance test with Megger 10,000

Volt.

Figure 3: Wet insulation resistance test with Megger 10,000

Volt.

Tests were carried out using 5000 Volt and 10,000

Volt meggers. The results of the insulation resistance

test using a megger are analyzed to get the leakage

current, as calculated below.

1. Analysis of leakage current at voltage of 5000

Volt

Voltage tested: 5.000 Volt DC

Insulation resistance: 250.000 Mega Ohm

The leakage current calculation:

I = V/R

= 5,000/250,000,000,000

= 0,02x10-6 amperes

= 0,02 micro amperes

2. Analysis of leakage current at voltage of 10.000

Volt

Voltage tested: 10.000 Volt DC

Insulation resistance: 500.000 Mega Ohm

The leakage current calculation:

I = V/R

= 10000/500,000,000,000

= 0,02x10-6 amperes

= 0,02 micro amperes

Through the same calculation, the leakage current

as displayed in table 1 at below.

Table 1: Analysis of leakage current of 20kV shaft with

megger 10kV.

Step of

testing

and

condition

R Iso.

at 5 KV

(Giga

Ohm)

R Iso. at

10 KV

(Giga

Ohm)

Leakage

current

at 5 KV

(mA)

Leakage

current

at 10

(mA)

1 dry 250 500 0.0200 0.0200

2 dr

275 550 0.0182 0.0182

3 dr

290 580 0.0172 0.0172

4 dr

300 600 0.0167 0.0167

5 dr

310 620 0.0161 0.0161

6 dr

330 660 0.0151 0.0151

7 dr

370 740 0.0135 0.0135

8 dr

390 780 0.0128 0.0128

9 dr

430 820 0.0116 0.0116

10 dr

440 880 0.0113 0.0113

1 wet 62 124 0.0807 0.0807

2 wet 75 150 0.0667 0.0667

3 wet 80 160 0.0625 0.0625

4 wet 82 164 0.0609 0.0609

5 wet 67 134 0.0746 0.0746

6 wet 73 146 0.0684 0.0684

7 wet 78 156 0.0641 0.0641

8 wet 80 160 0.0625 0.0625

9 wet 65 130 0.0769 0.0769

10 wet 78 156 0.0641 0.0641

Maximum

leakage

current

0.0807 0.0807

Lower

insulation

62 124

Based on the data in table 1, the variation of the

data can be illustrated by the graph in figure 4 below.

Variations in insulation resistance are affected by the

weather at the time of operation.

Safe and Secure Shaft to Support Robotic Hand on Live Line Operation

783

Figure 4: Graph of insulation resistance 5000 volt wet and

dry conditions.

Figure 5: Graph of insulation resistance 10000 volt wet and

dry conditions.

The insulation resistance value of the 20kV shaft

in dry conditions by applying a test voltage of 5000

Volts and 10,000 Volts, one of which is 250 Giga

Ohms and 500 Giga Ohms. The value of the

insulation resistance of the 20kV shaft in wet

conditions by applying a test voltage of 5000 Volts

and 10,000 Volts, one of which is 62 Giga and 124

Giga. This insulation resistance value is obtained

from an average of 10 times the leakage current of the

20kV shaft test. The minimum insulation resistance

of the shaft is more than 100 Mega Ohms. The

minimum insulation benchmark for medium voltage

is 100 Mega Ohm (Post et al., 2020).

The value of the 20kV shaft leakage current in dry

conditions by applying a test voltage of 5000 Volts

and 10,000 Volts of 0.0200 microampere. The value

of the 20kV shaft leakage current in wet conditions

by applying a test voltage of 5000 Volts and 10,000

Volts of 0.0200 micro amperes. So it can be said that

the leakage current is lower than 1 milli Ampere (

Saba et al., 2014). The standard maximum leakage

current that has no effect on shock to the human body

is 1 milli ampere.

To determine a safe electrical working distance,

there are two conditions that must be discussed for a

20kV shaft, namely dielectric strength, total distance

and distance between potential live voltage

equipment and workers when operating a robotic

hand that attaches insulators to medium voltage

equipment.

The rain angle is estimated to be a maximum of

30 degrees. Wet conditions decrease the dielectric

strength. There are 6 rubber rings like an umbrella to

protect the shaft from getting wet. Part of the dry shaft

is protected by a rubber ring to maintain dielectric

strength. Thus, the dielectric strength distance of the

insulator fixing robot hand tool in the tension

insulator clamp can be calculated as described below.

Figure 6: Rubber rings on 20kV shaft as safety.

If the shaded triangle in figure 6 is copied and

pasted, it will be obtained as shown in figure 7 below.

Figure 7: Angle distance.

Dry distancing calculation

Sin Q = Y/Z

Dry Distancing = 1,5/sin 30

= 1,5/0,5 = 3 cm

Total Dry Distancing = 6 x 3 cm = 18 cm

The normal air dielectric strength is 30 kV/cm

(Saba et al., 2014). The total dielectric strength of

grounding shaft with 6 pieces rubber ring is:

ℰ =ℰ0 xd

ℰ = 30 x 18 = 540 KV

200

400

600

12345678910

Dry Wet

500

1000

12345678910

Dry Wet

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The minimum creepage distance on the 20 kv

shaft is 81%, it can be seen through the following

calculation. Total length of shaft= Length of shaft +

total dry distancing

= 300cm + 18cm

= 318cm

Minimum creepage distance of shaft =

Total shaft length - worker grip distance

= 318-60

= 258

Minimum creepage distance= 258/318 x100% =

81%

The total dielectric strength of the 20kV shaft as a

robot hand operation aid with mathematical

calculations is 540 kV. As shown in Figure 4 a 20kV

shaft has a length of 3 meters. Thus the 20kV shaft is

qualified to maintain the distance between the worker

and the active part of the 15 kV phase to the ground

with a minimum distance of 60 cm (Ghosh et al.,

2015). The medium voltage distribution system in

Indonesia is only 11.6 KV lower from phase to

ground.

3.2 Discussion

Based on table 1, it can be seen that the maximum

leakage current value is not more than 1 Ampere and

the minimum insulation resistance of the grounding

shaft is not less than 100 Mega Ohms (Jondra et al.,

2020). The higher the voltage applied to the insulator,

the leakage current value is increased (Negara et al.,

2021). The standard maximum leakage current that

has no effect on shock to the human body is 1 milli

ampere. Based on the results of the safety distance

analysis, two values were obtained for assessing the

feasibility of a 20 kV shaft, namely: the value of

dielectric strength and the distance between workers

and active parts with potential for voltage release.

The analysis found that the 20kV shaft has a

dielectric strength of 540 kV, and provides a safe

distance between workers and live parts of 300 cm.

The total dielectric strength benchmark must exceed

the active voltage to avoid electric discharge (Saba et

al., 2014). The benchmark for the minimum safe

distance between workers and 15 kV active equipment

is a minimum of 60 cm (Ghosh et al., 2015).

4 CONCLUSIONS

The requirements that must be met by the Robot Hand

Installing Insulators in Medium Voltage Air Line Pull

Insulators (SUTM) are that they can be remotely

controlled and are able to close all insulator clamps

perfectly, have a high level of security such as not

delivering electric current to the linesman or work

executors on during operation, the weight of the robot

hand is according to the plan, which is appropriate

and can be easily lifted up and the 20kV shaft tool on

the robot hand is safe for medium voltage distribution

systems with A3CS cables. This feasibility is

determined based on good connection ability, leakage

current, insulation resistance, dielectric strength, and

safety distance. The results show that the shaft

exceeds the specified requirements. The insulation

value is more than 100 Giga Ohm, the leakage current

is lower than 1 milliampere, the dielectric strength is

more than 11.6 kV, and the worker distance to live

parts is more than 60 cm to make the system in a safe

state.

ACKNOWLEDGEMENTS

This research was funded by Lembaga Pengelola

Dana Pendidikan and Direktorat Jenderal Pendidikan

Vokasi Kementrian Pendidikan, Kebudayaan, Riset

dan Teknologi 2021. We thank Director of Politeknik

Negeri Bali for his support to this research and we

thank Project Management Office of Domestic

Vocational Higher Education Program Implementation

of the Applied Scientific Research in 2021 for his

support to this research.

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