Lightning location system in Croatia

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1 Lightning location system in Croatia Dr. sc. Boško Milešević Bojan Franc, dipl. ing. Prof. dr. sc. Ivo Uglešić Izv. prof. dr. sc. Viktor Milardić Dr. sc. Božidar Filipović-Grčić Nina Stipetić, mag. ing. December 2017

2 Presentation outline Lightning simplified physical model Lightning location system LINET LLS measured lightning data Lightning statistics for Croatian TSO Protection of overhead lines from lightning Conclusion 2

3 Lightning simplified physical model Electrical charge in the clouds 3

4 Lightning simplified physical model Typical lider progression and multiple lightning flashes a) b) c) Charge separation Lider progression First stroke d) e) f) First stroke discarge Second flash progression Second flash discharge 4

5 Lightning downward stroke Downward stroke to the ground First stroke Multiple stroke 5

6 Lightning downward stroke Upward stroke to the towers 6

7 Lightning location system LINET sensor positions 7

8 Lightning detection Lightning stroke (offshore Dubrovnik) Lightning sensor measures magnetic flux in time in frequency range (1 khz 200 khz) VLF/LF frequency range for detection of lightning strokes TOA (Time-Of-Arrival) method for locating lightning LINET 3D algorithm for determination of lightning altitude Data flow: Sensors -> LINET center -> Users 8

9 Isokeraunic map of Croatia ITALY HUNGARY BOSNIA AND HERZEGOVINA Isokeraunic map annual thunder days expected with 50 % probability 9

Thunderstorm movement monitoring 12.9.2017.

10 Thunderstorm movement monitoring h 24h * 1h frames lightning strokes detected 10

11 LLS measured lightning data 9 years of lightning data Number of lightning strokes No. of Lightning Strokes by Year 16,000,000 14,000,000 13,976,505 12,000,000 10,722,880 10,000,000 8,000,000 6,532,464 6,254,829 5,791,438 6,000,000 4,796,048 4,682,585 4,758,966 4,680,014 4,430,847 3,822,951 3,656,555 4,000,000 8,964,239 7,400,058 5,625,625 4,655,689 3,253,625 2,000,000 1,736,416 1,572, ,015 1,023,459 1,360,591 1,564, , Year Ukupno Total Oblak-Zemlja CG Oblak-oblak IC 11

12 LLS measured lightning data Cumulative amplitude distribution Negative polarity Cloud to ground strokes Optimization of Lightning detection algorithm at the end of 2015 Better detection of small current lightning in

13 Measured Lightning Data Cumulative frequency of lightning occurrence IEEE distribution LLS measurements I peak current IEEE: M = 31 β = 2,6 LLS: M =

14 Lightning Correlator Lightning Location System Geographic Information System Supervisory Control And Data Acquisition 14

15 Lightning activity close to 220 kv line Konjsko - Orlovac :20h 17:20h * 10 min interval X CG X CC 15

16 LLS spatial correlation GIS data on transmission network Spatial correlation with lightning data 16

17 Lightning statistics for Croatian TSO Transmission network 339 lines 110/220/400 kv AC km kv 220 kv 110 kv Total No. of transmission lines Transmission lines length [km] Alarm zone surfaces [km 2 ] No. of strokes No. strokes / 100 km of transmission line Stroke density [stroke / km 2 year]

18 Lightning statistics for Croatian TSO SCADA registered CB (circuit breaker) operations CB operations due to lightning CB operations due to close strokes (near short circuit) kv 220 kv 110 kv Total No. of line bays Total No. of CB operations No. of operations / No. of line bays No. of correlated CB operations No. of correlations / 100 km line length No. of operations CB due to close strokes

19 Isokeraunic level of Croatia Rijeka Zagreb Osijek Transmission region Number of correlated CB operations Split 146 Rijeka 98 Split Osijek 12 Zagreb 6 19

20 Lightning statistics for Croatian TSO CB operations due to lightning per voltage level CB operations due to lightning per transmission region Number of Transmission region correlated CB operations Split 146 Rijeka 98 Osijek 12 Zagreb 6 Total 262 Number of Voltage level correlated CB operations 400 kv kv kv 238 Total

21 LSAs operation on OHL 110 kv Ston - Komolac Line lenght: 44 km 110 LSAs (Line Surge Arresters) zinc oxide surge arrester installed in July 2007 Configuration obtained by computer simulations Overhead line parameters, grounding tower resistance Results not applied completely Modified twice during the first six years of operation 6 LSAs dismantled due to mechanical damages 50 towers with 1 LSA, 24 towers with 2 LSAs and 2 towers with 3 LSAs 21

22 110 kv transmission network of the island of Brač OHL 2 OHL 1 23

23 Line Surge Arrsters installation OHL kv OHL Nerežišća Stari Grad - Line section lenght: km - 25 LSAs installed - 3 towers with 1 LSA, 8 towers with 2 LSAs, 2 towers with 3 LSAs OHL kv OHL Dugi Rat Nerežišća 2 - Line section lenght: km - 20 LSAs installed - 15 towers with 1 LSA, 1 tower with 2 LSAs, 1 tower with 3 LSAs LSAs zinc oxide surge aresster: U c = 78 kv, U r = 108 kveff, IEC Class: II, Nominal discharge current: 10 ka, Discharge current withstand strength (4/10 μs): 100 kapeak 24

24 Tower data Line One-circuit Tower Steel-frame Conductors 240/40 - Al/Steel Shielding wire ACS OPGW R d1 [Ω/km] X d1 [Ω/km] R 01 [Ω/km] X 01 [Ω/km]

25 Tower data 26

Future projects for LSAs implementation 4 Overhead line sections of transmission lines: 1-110 kv Ston-Ponikve equipped with LSAs in 2015 2-110 kv Ponikve Blato

26 Future projects for LSAs implementation 4 Overhead line sections of transmission lines: kv Ston-Ponikve equipped with LSAs in kv Ponikve Blato on the peninsula Pelješac and island Korčula kv Blato Stari Grad on the island Korčula and island Hvar kv Nerežišća Stari Grad on the island Hvar 3 2 1

27 Conclusion Lightning location system in Croatia benefits for all technical systems Time and spatial correlation of the relay protection system data and LLS data Number of outages of OHLs in relation to the lightning activities decreased Possible improvements and further analyses needed Future application to OHLs in the Southern part of Croatian transmission network 28

28 Lightning location system in Croatia Dr. sc. Boško Milešević Bojan Franc, dipl. ing. Prof. dr. sc. Ivo Uglešić Izv. prof. dr. sc. Viktor Milardić Dr. sc. Božidar Filipović-Grčić Nina Stipetić, mag. ing. December 2017

Correlation between Lightning Impacts and Outages of Transmission Lines. H-D. BETZ Nowcast GmbH Munich Germany

CIGRE C4 Colloquium on Power Quality and Lightning Sarajevo, Bosnia and Herzegovina, 13 16 May, 2012 Paper 01. Correlation between Lightning Impacts and Outages of Transmission Lines I. UGLEŠIĆ V. MILARDIĆ