Seismic Performance of Interconnected DC Field Equipment in UHV Converter Substation

Abstract

In order to compare the seismic performance of interconnected DC field equipment in the UHV converter substation, the paper establishes finite element models of four different types of connection schemes. Taking 400 kV field equipment as the research object, seismic responses of four types of connection schemes, which include rigid conductors with fixed fitting, sliding fitting, and flexible conductors of two different sag-to-span ratios, were compared. The results show that the post insulators connected with the loop device have larger seismic responses. Interconnection mode has a huge influence on the displacement and acceleration responses of the device. The lower frequency device connected by flexible conductors has an obvious unidirectional oscillation phenomenon of displacement and acceleration. There exists a critical value of the sag-to-span ratio. The sag-to-span ratio of flexible conductors below the critical value will cause a larger peak seismic response of the device in the loop. The analyses reveal that rigid conductors with fixed fittings can be adopted in the lower intensity of seismic fortification because of fine integrity and smaller displacement. Both sliding fitting connections and flexible conductors are suitable for the area with high seismic intensity in view of smaller acceleration response. Meanwhile, the setting of the sag-to-span ratio should be paid attention to the flexible conductors.