Some practical aspects of overvoltages on the CEGB transmission system

The paper reviews the insulation co-ordination policy of the CEGB and the main practical aspects of investigations into various types of overvoltages. Faults resulting from external and internal overvoltages are compared with those due to other causes. Overvoltage problems and remedial measures are appraised in the light of the insulation co-ordination policy adopted by the CEGB.