Experimental and numerical investigations of the effects of bundled conductor on seismic responses of interconnected electrical equipment

With a main function of power transmission, bundled conductors bring in strong nonlinearity for the connected electrical equipment in substations. Investigations of their effects on seismic responses of interconnected electrical equipment (IEEQ) are few in literature, lacking studies from an experimental perspective. Thus, shaking table tests were performed on a scaled ultra-high voltage IEEQ. The tests examine the effects of slackness, bending stiffness, number of spacers, and damping of the bundled conductors. Besides, the influence of earthquake input directions is also analysed. Moreover, a numerical model is developed to conduct parameter analyses to investigate the influence of bundled spacing and equipment frequency. The results indicate that the connection of the conductors reduces the IEEQ relative displacement. It overall increases the stress responses of the higher-frequency equipment while reduces those of the low-frequency equipment. The effects of slackness are related to the damping and stiffness effects of bundled conductors, since the latter can decrease the seismic responses of the IEEQ. Besides, the effects of bundled conductors on the out-of-plane and vertical responses of the IEEQ can be neglected per the test results. Finally, bundled conductors may twist during earthquakes, the spacers thereby should be positioned appropriately to prevent this issue.