A Remote Surge Analyzer to Monitor Zinc Oxide Arrester Performance

In theory, arresters connected between phase conductors and tower would reduce flashovers on transmission line towers located in areas where low footing resistance cannot be readily obtained. To test this concept, 75 metal oxide arresters specifically designed for the application were installed on 138 kV lines in the Blue Ridge Mountains of southwest Virginia. Transmission lines in the area have frequent lightning-induced flashovers related to high tower footing resistance. A field test program was instituted to monitor performance of the arresters with the lines energized and carrying load under normal operating conditions. A special surge analyzer has been developed to record the peak current, ampere-time integral and polarity of tower and arrester currents during a lightning strike event.