Lightning Protection for Distribution Transformers

This paper presents a five year history of the results of lightning arrester protection for distribution transformers in New England where the normal ground electrode resistance is much higher than in most other parts of this country. The experience shows that the trouble rate of the protected transformers has consistently been materially less than that of those not protected, notwithstanding the seemingly adverse conditions. It also shows that the effectiveness of the arresters is practically independent of the ground resistance when above a value of 100 ohms. Design features of transformers are shown to be of prime importance in reducing flashovers in and around the equipment.