Effectiveness of Line Surge Arrester Application on the 132kV Kuala Krai - Gua Musang Line

摘要

The Transmission Division of Tenaga National Berhad (TNB), Malaysia manages and operates the 132kV, 275kV and 500kV transmission systems that form an integrated network known as the National Grid. TNB's National Grid system spans the whole of Peninsular Malaysia that represents the backbone of the electricity industry and the Transmission Division is responsible for the safe, adequate, reliable and economical operation of the grid system in conformance to the Malaysian Grid Code. Malaysia being in one of the highest region of lightning is experiencing a tremendously high number of lightning strikes every year, thus giving a very high Ground Flash Density (GFD) value. This high GFD value has very much affected the performance of the Distribution and Transmission lines owned by TNB. The line with the highest recorded lightning tripping in Peninsula Malaysia is the 132kV Kuala Krai (KKRI) to Gua Musang (GMSG) line which is located in the North-East of Peninsular Malaysia. The 113km 132kV KKRI-GMSG line consist of 295 towers, commissioned in 1995 with a double circuit line configuration. The line has recorded a tremendous number of 55 trippings; 11 are single circuit trippings and 22 are double circuit trippings. The calculated actual trip rate for 12 years (2001 - 2013) is 4.58 trip/km.year. The rate is considered as unacceptably high comparing to the average trip rate recorded for TNB's 132kV lines, which is 1.8 trip/100km.yr. Elsewhere in other utilities, the acceptable trip rate for 132kV lines are generally 1.5 to 2.8 trip/100km.yr. A lightning performance study was conducted to evaluate the line lightning performance and to explain the 'un-effectiveness' of the installed Transmission Line Arrester (TLA) on the line since 2007. The line was installed with more than 120 units of TLA since 2007 until 2012. TFlash software by EPRI USA and SIGMA SLP by Sadovic France was used in the study. An interesting outcome from the simulation result is presented in this study.