Analysis of Transformer failure due to lightning on Haugaland Kraft power line distribution network

Abstract

The transformer plays an important role in transmission and distribution of electric energy. A lightning causes a seriously problems in damaging electrical line equipments such as transformers. The Haugaland Kraft transformers were damaged due to the thunderstorms. When lightning strikes direct or indirect to the power line, the electrical pulse travels along the conductor, generating a very high additional current in the power line distribution network which in turn leads to an overvoltage. The transformer failure was caused by the higher lightning energy exceed the withstand capability of the power line equipment. The improvement to the protection of the distribution transformer was based on the analysis of parameters which will help to reduce the induced overvoltages. The best method was found to be the placement of the protective equipments in the power line and the selection of the surge arrester which is the main material used in protecting transformer. This analysis resulted into consideration of improving the significance parameters which will help to reduce the induced lightning voltage. There will be needed the installation of OGW and the selection of surge arrester residual voltage. The use of a new surge protective called Strikesorb must be used to protect the transformers against lightning strikes. The distance from the protected transformer to the surge arrester must be considered in order for the transformer to be protected.