Extended Mast Terminal for Lightning Protection System Improvement

on transmission Lines in Indonesia

Prof.Dr. Reynaldo ZoroLightning Research CenterSchool for Electrical Engineering and InformaticsInstitut Teknologi Bandung – ITBBandung - Indonesia

Content

• Introduction • Lightning Data• Lightning Protection System • Experience on Improvement of LPS for HV and EHV

lines

Indonesia; Maritime ContinentSt. Petersburg, Rusia

Java Island & Bali

Bali IslandEast Java

Overvoltage due to Lighnting at Transmission Lines

Improvement of LPS

Conventional

• Grounding System• Ground Wire • Insulators• Surge Arrester & Transmission

LineArrester

Grounding System….

7

Natural Grounding

• Using the additional iron bar inside the fondation structure

• According to IEC 62305 – 1 / 2006

GROUNDING IMPEDANCEGROUNDING IMPEDANCE

Overhead Ground Wire….

11

THREE OHGW 275 kV Lines

12

Insulators….

13

BACK FLASHOVER ON TRANSMISSION LINE

TOWERBackflashover voltage :

Vin = R.i + L.di/dt

050

m675.3

m35.3

m45.3

m575.3

m4.5

m5.6

Disc1816

m5.7

m5.6

Disc1816

Disc1816 m5.44

'R

'S

'T

Tipycal Configuration of EHV 275 kV Lines

Removed and installation of tower insulator at Tower 130 L1 & 2 (20 disc) on 25 & 26 June 2002

TOWER no. 103 at 500 kV line Sub. Kediri – Sub. Paiton

18

Installation of TLA with MOA at 150 kV Line

PROTECTION DISTANCE

SURGEARRESTER; L = (Ut – Ua). v

2.( x di/dt) L (meter)Ut BIL Transformer (kV)Ua Voltage Discharge SA (kV)

du/dt = x di/dt (kV/us)di/dt Steepness of impuls current (kA/us) Surge Impedance (ohm)

Protection Distance of Arrester at HV 150 kV Substations

L1

L2

Ltotal = L1 + L2

LIGHTNING DATA….

22

EHV Lines 500 kV JAVA - BALI

24

Lightning Flash Density di Java IslandRecorded by Indonesian LDN

Arus Puncak Petir

Prob

abilit

as

4

5

Statistic of Lightning Current in Tropical and Sub-Tropical Area

Europe by Karl Berger, measured at Mt San Salvatore, Switzerland : (1) petir pertama total, (2) petir negatif, (3) petir positif. Indonesia by Reynaldo Zoro, measured at Mt Tangkuban Perahu : (4) petir negatif, (5) petir positif

26

4

5

Kecuraman Arus Petir

Probabilitas

2

1

Statistic of steepness of lightning current in tropical dan sub-tropical area

(1) Europe by Karl Berger, measured at Mt San Salvatore, Switzerland. (2) Indonesia by Reynaldo Zoro, measured at Mt Tangkuban Perahu

Summary of lightning characteristic in Indonesia

Lightning Characteristic Negative Polarity Positive Polarity

Peak Current( i )

Maximum T. Perahu 280 kA 298 kA

Jawa Barat 335 kA 392 kA

Probability 50 % 40 kA 18 kA

Average 41 kA 30 kA

Steepness Maximum (kA/s) 119 120

(di/dt) Probability 50 % (kA/s) 30 20

Flash Density (strikes/km2/year) 4,1 – 12,4 1,5 – 3,8

Flash Density total (strikes/km2/year) 7,9 – 15,5

LIGHTNING PROTECTION SYSTEM ….

28

INSTALLATION OF EXTENDED MAST TERMINAL (EMT)

FOR TOWER PROTECTION ….

29

Vin = R.i + L.di/dt

Figure 1. Lightning Strikes around EHV lines 500 kV Paiton Kediri (square : higher lightning density) & location of research towers.

Lightning Strikes around EHV lines 500 kV Paiton Kediri (square : higher lightning density) & location of research towers.

TOWER 353

TOWER 103

EMT on 500 kV Paiton-Kediri (as extended mast)

Proteksi Tower 500 kV dengan EMT

Result of Magnetic Tape Peak Current Measurement

Tape Type I II Chrom IV FerroT erased

(s) 0 0.74 0.667S erased

(cm) 0 3.552 0.667Peak Current

(kA) 8.23 12.656 7.77

05/07/23 courtessy of Dr. Ir. Reynaldo Zoro 36

Result of Measurement (temporary results)

NONO DATEDATE CURRENT (kA)CURRENT (kA)

11 6 February 20076 February 2007 2626

22 12 February 200712 February 2007 3838

33 15 March 200715 March 2007 2828

44 14 November 200714 November 2007 5454

55 16 December 200716 December 2007 4646

66 8 January 20088 January 2008 2222

77 28 February 200828 February 2008 2828

88 19 November 200819 November 2008 3333

Insulator Broken Data compare to Severity Index

No Nomor Severity Isolator Menara Index Pecah

1 97 13.508 25 2 101 12.870 27 3 23 12.793 9 4 98 12.461 6 5 250 12.342 7 6 103 11.895 17 7 324 11.753 4 8 102 11.658 26 9 104 11.577 3

10 22 11.031 14 11 455 10.967 0 12 24 10.583 4 13 249 10.453 2 14 454 10.103 1 15 477 10.047 1 16 443A 9.975 5 17 353 9.937 1 18 471 9.865 4 19 325 9.809 2 20 446 9.705 2 21 235 9.669 0 22 447 9.584 1 23 245 9.545 0 24 248 9.497 0 25 234 9.466 0

H = 376 m

Double shielded down conductor1 x 70 mm²

Lightning Rod Isolated from the Tower

Bordes for Measuring & Maintenance

Foundation Grouding & Counterpoise

Conclusion• Lightning Protection System using Extended Mast Terminal is a new

innovation compared to the conventional protection used used at transmission lines.

• Lightning strike on Extended Mast Terminal will prevent lightning current parameter to “read” the towers parameters. The lightning current will only flow inside double shielded down conductor cable which has very low inductance value ( < 0.03 microHenry/meter) and it will reduce the tower voltages due to the steepness of the lightning current and reduce also the voltage stress accros the insulators and prevent back flashover.

• Installation of Extended Mast Terminal at tower 353 and 103 on 500 kV EHV lines Paiton-Kediri prevent back flashover that lead to the insualtors damages. No broken insulators were found after installing the EMT on tower 353 and 103 since early 2007.

• Lightning strikes data collected during period of 2007-2008 indicate that the installation of EMT have protected the tower from lightning direct strikes.

Thank You….

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