Abstract: A lightning protection device for reducing exposure of an object to be protected from conventional and upward lightning strikes. The device includes a support structure adapted to be grounded and space charge producing conductors wound around the support structure and forming coils for producing space charge of opposite polarity to a cloud charge, in a proximity of the object to be protected. The space charge induces a charge on the object to be protected of an opposite polarity to a charge induced on the object to be protected by the cloud charge and inhibits a formation of streamers from the object to be protected. Each space charge producing conductor has a diameter not exceeding 0.1 mm for reducing a corona inception voltage of the support structure upon which each space charge producing conductor is wound, in both dry and wet conditions.

Abstract: A method and apparatus for detecting defective insulators in an insulating column supporting an electrical conductor in a power line. The column is made of a plurality of serially connected insulator members. Voltage present on the conductor supported by the column generates an electric field about it. The presence of faulty insulators within the column causes field redistribution and discontinuities in it. A specially configured electric field probe is provided to measure at predetermined distance and locations, this electric field. A displacement device is provided whereby to displace the probe along an axis substantially parallel along the length of the column to automatically obtain measurements. Means to analyze the measurements are provided and allow to identify the defective insulators whose positions correspond to the locations of the discontinuities in the electric field surrounding the column. The main advantage of this method is that no electrical contact need to be made to the insulators.