lightning protection of medium voltage overhead lines
Post on 30-Dec-2015
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1George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
LIGHTNING PROTECTION OF MEDIUM VOLTAGE OVERHEAD LINES
• WITH COVERED CONDUCTORS BY ANTENNA-WITH COVERED CONDUCTORS BY
ANTENNA-TYPE LONG FLASHOVER ARRESTERS A
ALFA
2George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Lightning protection diagram
1 – thunderstorm cloud; 2 – lightning channel; 3 – space charge;
4 – pole; 5 – insulator; 6 – insulator flashover channel; 7 – binding;
8 – insulating cover; 9 – conductor’s core; 10 – surface flashover channel; 11 – piercing
clamp.
3George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
ALFA operating principle
12 – electrode; 13 – antenna
4George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Protection of MV line by ALFA
14 - insulator; 15 – steel pipe
5George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Line mock -up testing
6George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Equivalent circuit diagram
Ul - lightning potential Uа - antenna potential
Clа - lightning-antenna Cаg - antenna-ground
R - leakage resistance
7George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Antenna potential vs. time to breakdown
8George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Simplified test outline
simulation of lightning leader approaching a line
U
9George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
Simplified test outline
simulation of lightning final stroke
U
10George Podporkin Ru Session 2 – Block 1 – Paper 19
Barcelona 12-15 May 2003
– ALFA flashovers well before a direct contact of the channel with a conductor.
– ALFA protects the line against both induced overvoltages and direct lightning strokes.
– A simple design makes ALFA less expensive than conventional metal oxide arresters.
CONCLUSIONS
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