Utilization of polymer enclosed intermediate class arresters to improve the performance of modern power systems

The authors introduce the first commercially available polymer-enclosed intermediate class metal oxide surge arrester. The unique construction of the design, including reduced size, increased flexibility, a collared seal on the polymer housing and an open webbed fiberglass-epoxy module which houses the metal oxide disc elements is described. Performance advantages are discussed. These include improved short-term contamination performance of the insulator-like polymer design when compared to multi-unit porcelain housed designs. Data show that polymer-housed open-webbed fiberglass module construction extends the pressure relief capability beyond that of typical porcelain-enclosed designs. The capability of the polymer-enclosed design to withstand repeated pressure relief tests, simulating system reclose on a failed arrester, is discussed. The circumstances at one utility which has considered utilizing polymer-enclosed intermediate class arresters to effectively upgrade their system protection capabilities are discussed. Some suggested changes to the current ANSI C62.11 standard relative to testing polymer-enclosed intermediate class arresters are addressed