Seismic evaluation of ±800 kV UHVDC disconnect switch by shake table test

Abstract

Disconnect switches, the widely used electrical substation apparatuses, however, were severely damaged in several earthquakes, causing huge economic losses. Disconnect switches with higher voltage are more vulnerable to earthquake for their great height and flexibility. The interaction between posts and blades might magnify the seismic responses, which is not fully understood and deserves further investigations. Therefore, a full-scale shake table test on a new-style latticed ±800 kV ultra-high voltage direct current disconnect switch was carried out to evaluate its dynamic properties and seismic responses. Two different operational conditions with the main blade open and closed were tested, respectively. Interaction between posts and blades was studied via acceleration amplification factors and the spectrum analysis. The test result indicates interaction only exists in the length direction, and will amplify seismic responses of the post with the main blade, while reduce those of the post with the fixed contact. Moreover, the seismic responses of specimen are smaller than those in previous studies, suggesting the latticed structural form alleviate the negative effects induced by the great height and flexibility, and is helpful for structural design of disconnect switches.

Keywords

• earthquake engineering
• dynamic testing
• HVDC power transmission
• structural engineering
• switchgear
• seismic evaluation
• seismic responses
• full-scale shake table test
• main blade
• ultra-high voltage direct current disconnect switch
• electrical substation apparatuses
• UHVDC disconnect switch
• acceleration amplification factors
• spectrum analysis