Experimental investigation on the dynamic behavior of flexible conductors between substation equipment during an earthquake

The effects of connections made of flexible conductors must be included in the seismic design of substation equipment. A common practice is to take account of their effects as static loading only, providing sufficient slack to permit the expected relative displacement between interconnected equipment during an earthquake. This paper presents the approach and the results of an experimental study performed to investigate the significance of the dynamic behavior of connections made of flexible conductors under earthquake excitation. It is found that they can be excited in resonance and generate significant forces on the equipment to which they are interconnected, even when sufficient slack is provided. The study shows that the dynamic reactions of connections must be considered for the proper design of substation equipment. A method of establishing the natural frequencies of connections likely to be excited during an earthquake is proposed.