GB/T 32520-2016

This standard applies to outdoor string-type metal oxide surge arresters (hereinafter referred to as EGLA) used in overhead transmission and distribution lines with voltages above 1 kV, which are designed to protect the line insulation from lightning-induced flashover or breakdown. However, the following issues related to EGLAs that are connected to the line via an external string-type gap are not considered in this standard: — Operating impulse discharge voltage; — Steep wave and operating impulse residual voltage; — Thermal stability; — Long-duration current impulse withstand; — Time characteristics of the surge arresters' withstand voltage under power frequency; — Disconnecting device test; — Aging caused by power frequency voltage. Considering the specific design concepts and special applications of overhead transmission and distribution lines, some unique requirements and tests have been introduced, such as verification tests for insulation coordination between insulators and EGLA protection levels, inrush current interruption tests, mechanical load tests, etc.