Lightning Arrester Field Test Equipment and Results

Lightning arresters play an important role in the protection of power system insulation against damage by surge voltages. Many arresters which have been in service a considerable number of years are still expected to provide this protection even for insulation that may not possess the strength as specified for new apparatus. The results of various methods used in the past to check arrester condition in the field are often questionable. A novel field test method for lightning arresters has therefore been developed. Impulse sparkover and power frequency leakage tests in the field can be carried out, with portable test equipment, on line-type and station-type lightning arresters with single-unit ratings up to 37 kv. Design and operating principles of this equipment are described; the field test results indicate that with the new method it is possible reliably to detect arresters not performing according to requirements.