LIGHTNING SIMULATION STUDY ON LINE INSULATORS (Surge arresters) (110kV Overhead Power Line "Fierze F. Arrez - HC Dardhe")

Abstract

During the designing phase of the line of a private power plant was made a study of howthe atmospheric discharges from lighting impulses could affect the working regime of a newpower Hydro Power plant under construction in the Dardhe Puke Area.The line under study is a short 110kV double circuit overhead power line composed of 3 steellatticed towers with a 120mm2 ACSR conductor and 66mm2 OPGW. The insulation of the lineis with 8 CAP PIN insulators type U120B and according to IEC 60071 (standard for insulation levels from 1 to 245kV) a 110kV power line should have a standard lighting impulse with standvoltage of 520kV.The insulation of the line has been modeled in the ATP software for each tower of the line.Standard lighting impulses of 10kA, 15kA, 60kA, and 120kA have been applied and we have seen the behavior of the line for each set of insulators on the towers to understand which lighting impulse would result in a flash over of the line insulation. The results of the viewed overvoltage traveling waves on the line and of the overvoltage's induced on the towers structure showed thatthe flash over of the insulation happened on the first tower which has the highest, grounding resistance for an impulse current of 15kA.Alternative Transients Program (ATP) is computer software used by the electric power industryfor simulation of electrical systems transients. This program develops subject "Platform for Overvoltage Calculation & Insulation Coordination" in Department of Electrical Systems ofPower.