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

The first commercially available polymer enclosed intermediate class metal oxide surge arrester is introduced. The unique construction of the design is described, 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. 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 also 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