03194nas|a2200397 i 4500 20260817162400.0 220200s1999 th uu m rtt 00| a1eng d .b11778386 AIT Thesis no.ET-99-17 Pham Quang Huy The analysis of lightning risk for a 500KV GIS substation : a case study in Vietnam Bangkok : Asian Institute of Technology, 1999 86 leaves Thesis ; no. ET-99-17 A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. School of Environment Resources and Development Thesis (M.Eng.) - Asian Institute of Technology, 1999 The major problem of insulation level of GIS substation is the overvoltages due to lightning, especially with high value of lightning current. This study concerned with electromagnetic transients to evaluate the failure risk of insulation of equipment. It is more importance because this study is applied for 500kV GIS substation, the new equipment with many advantages of small space requirement, low maintenance cost, low environmental impact, etc. In this study, modeling of the power system and lightning source has been done in the transient state. By using EMTP program, the overvoltages due to lightning have been calculated in various cases of changing lightning current, point of lightning impact, phase angle of power frequency voltage, i.e .. The overvoltage results inside the 500kV GIS are collected for evaluating the risk of failure. A method for estimating the risk of failure of an apparatus as a result of lightning strikes on the transmission lines has been developed to meet the requirements of quick and low-variability calculation. The results shown that with tower footing resistance is 10 ohms· or less, the risk due to lightning can be accepted. Otherwise, the solution to reduce the risk of failure for 500kV GIS substation could be carried out by installing surge anester, reducing tower surge impedance, re-arrange the spans, etc. The calculation can be used efficiently as a calculated process of substation design. Electric substations Vietnam Lightning protection Vietnam Surapong Chiraratananon, Chairperson Yu, Cun Yi, Examination Committee Dhadbanjan, Thukaram, Examination Committee Sida, Scholarship donor Asian Institute of Technology. Thesis ; no. ET-99-17 Full-Text http://203.159.5.9/ait-thesis/detail.php?q=B12781 .b11778386 mnait u 240421 0 000222 m a u 4 mnait mnarc 22 40 Barcode : 30050120731996 CREATED : 2014-03-02 RECORD # : i12754730 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 Barcode : 30050120365480 CREATED : 2016-06-15 RECORD # : i13037067 LPATRON : 0 LCHKIN : - # RENEWALS : 0 # OVERDUE : 0 IUSE3 : 0 TOT CHKOUT : 0 TOT RENEW : 0 4849 4849 0 0 0 0 MAIN MAIN mnait 2026-08-17 50.00 0 AIT Thesis no.ET-99-17 30050120731996 2026-08-17 16:24:00 3 2026-08-17 22 0 0 0 0 MAIN MAIN mnarc 2026-08-17 0 AIT Thesis no.ET-99-17 30050120365480 2026-08-17 16:24:00 2026-08-17 40