STUDY OF LIGHTNING PROTECTION SYSTEM ON 275 KV OVERHEAD TRANSMISSION LINES IN TROPICAL AREA

• Main Author: MURDIYA, FRI
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/12135
• Institution: Institut Teknologi Bandung

The theses has investigated lightning protection system on INALUM Co. 275 kV overhead transmission lines, location in North Sumatera near equatorial belt. Lightning data acquired from BKMG North Sumatera present total cloud to ground lightning flashes frequency are 500-10.000 flashes in this area during 2006-2007. Lightning protection system on this overhead transmission lines has installed three overhead ground wires (OHGW) and negative shielding angel, 22 pieces of porcelain insulator, and tower footing resistance designed 10 ???? by counterpoises grounding. After construction works of INALUM Co. 275 kV transmission lines (1982 until now), damage ground wire and arcing horn have occurred, due to lightning stroke. Lightning peak current distribution on each tower have recorded by magnetic link. Shielding failure analysis by electro geometric concept (EGC) and finite element method (FEM) in PDEtool Matlab programming, using electrostatics mode, show that shielding failure flash over rate is zero. Estimation of lightning performance by Whitehead concept, for Ng = 6 flashes/km2/year ,FOR is 0.24 flashes/100km/year. It is “Excellent grounding and shielding” for CIGRE/IEEE probability lightning peak current. However, for Zoro, etc. probability lightning peak current, FOR= 0.32 flashes/100km/year. It is “Good grounding and shielding”. Between CIGRE/IEEE and Zoro probability lightning peak current are significant different. Proposing to install three OHGW than two OHGW in the new 275 kV T/L system, it reduce BFOR at 57%. For some application, where the cost of three OHGW is not economically and technically justified, or where there is low ground flash density, two OHGW can be used. Simulation by ATP program, result of the combination three and two OHGW reduce tower peak voltage due to lightning strike until 14.7 % than two OHGW only.