Distribution system lightning protection; Interconnection of primary arrester ground and secondary neutral

Although distribution transformers have high impulse strength compared to their normal voltage ratings, they still flash over and fail in service even when protected by arresters. Interconnecting the ground lead of the primary arrester with the transformer secondary neutral limits the voltage across the transformer insulation to that permitted by the arrester alone, and introduces no additional hazard on the low voltage circuit where secondary neutral ground resistances are low. This is the first group of articles dealing with the subject of protecting distribution systems from lightning; articles dealing with other phases of the problem will appear subsequently in ELECTRICAL ENGINEERING.