Testing and modelling hollow-core composite station post insulators under short-circuit conditions

Hollow-core composite 230-kV station post insulators have been tested with single-phase short-circuit currents, simulating levels up to 85 kA rms-symmetric current (worst-case offset for an outer phase) in a three- phase system. Acoustic emission measurements indicated that these non-ceramic insulators (NCI) were not damaged by the short-circuit tests. Finite-element modelling of the insulator-bus system provided a good description of the tests. The finite-element modelling was used to calibrate a simpler model for station design, similar to the models upon which the ANSI/IEEE Standard 605 [ANSI/IEEE, 1984] and the IEC Standard 865 [IEC Standard, 1986; The Mechanical Effects of Short-Circuit Currents, 1996] are based.