Abstract :
Today corona measurements are used in many instances as part of testing electrical insulation materials and equipment. Also, corona tests are performed for other purposes The prerequisite for obtaining economical benefits from corona testing is a sufficient understanding of the nature of corona, its effects on materials and the performance of electrical systems, corona measurement techniques and their use in evaluating the performance of the tested objects. The factors which are the basis for success in making corona measurements are reviewed and recently published new information is presented about problems in specifying corona tests and test equipment, as well as evaluating test results. It is concluded, that more benefit can be derived from corona testing and that using it on a much wider scale than today is economically justifiable, if full use is made of the available knowledge about corona, corona measuring techniques and their use in insulation system evaluation, as well as of the remarkable flexibility modern corona test equipment offers for its use in other phases of electrical testing.