High-Energy Solid-State Electrical Surge Arrestor

In this paper an engineering model of a high-energy (20 ~ 40 C of charge, 15 ~ 35 kJ) solid-state electrical surge arrestor (ESA) is presented. The basic elements are commercial or custom-made metal oxide varistors (MOV). The approach to achieve a high-coulomb ESA is to use paralleled MOV´s with efforts concentrated on ensuring uniform current partition by matching the MOV´s conduction characteristics and using ballast resistors. The unit with custom-made large area MOV´s survived consecutive 40-C surges of 5-ms exponential decay. The peak current was 6.5 kA at a clamping voltage of 1.1 kV. Design consideration, screening techniques, packaging, and test results are reported. A brief review of the MOV physics is also included.