Seismic testing and modeling of cylindrical electrical equipment with GFRP composite insulators

Glass fiber reinforced polymer (GFRP) composite is a desirable alternative to porcelain for insulators of cylindrical electrical equipment in electrical substation. However, mechanical properties of composite insulator in an event of earthquake are not fully known yet. This study aimed to investigate both the static and dynamic properties of GFRP composite insulators and electrical equipment through impact hammer test, quasi-static flexural tests and full scale shaking table tests. The flexural properties, in terms of flexural stiffness, damping and hysteretic behavior, were investigated, based upon which a mechanical model was proposed. Moreover, the possible failure modes were identified in order that a design and qualification procedure was recommended for engineering application. The procedure has been further validated by a full scale shaking table test of 1000 kV cylindrical composite electrical equipment.