GB/T 19519-2014 provides for overhang and tensile composite insulators for overhead lines used in nominal voltages exceeding 1000V AC systems. It clarifies relevant definitions and covers concepts such as insulator structure and components. Test methods such as tensile, bending and electrical performance are elaborated, and test equipment and operation procedures are strictly standardized. At the same time, acceptance criteria are given to determine whether the product is qualified according to performance indicators. The standard provides the basis for the production, inspection and application of such insulators to ensure stable and safe transmission of high voltage AC overhead lines.