Seismic Evaluation of Ultra-High Voltage Wall Bushing

Abstract

A series of shaking table tests were carried out on a full-size polymer ultrahigh voltage wall bushing. In addition, a corresponding finite element model of the wall bushing was established. Four different earthquake ground motions—the El Centro, modulated Landers, Taft, and an artificial earthquake acceleration time history—were adopted in the study. Test results indicate that the safety factor of the wall bushing is less than the stipulated value of 1.67 in the Chinese code under the peak ground acceleration (PGA) of 2 × 0.4 g, where the factor 2 is used to simulate the amplification effect of the valve hall on the seismic responses of the wall bushing. Necessary slackness should be allowed for the conductors connected to the wall bushing because of the large displacement of the bushing terminals. There are relative displacements between the central conductor and polymer insulators during an earthquake. Increasing the out-of-plane stiffness of sealing plates at the terminals of the wall bushing could decrease the relative displacements. Moreover, a theoretical vibration model of the wall bushing was developed to demonstrate that the rocking effects of the installation plate and flange bottom plate have an influence on the seismic responses of the wall bushing.

Seismic performance improvement of ±800 kV UHV DC wall busing using friction ring spring dampers

“…The values were 3.01% in the Y direction and 2.86% in the Z direction, both of which are larger than the recommended maximum value of 2% in relevant standards (IEEE, 2018; MOHURD, 2013). In contrast, the damping ratios of the full-scaled model wall bushing without FRSDs were 1.14% and 1.23% (Xie et al, 2019a), revealing that the FRSDs enhance the damping of the wall bushing in both directions.…”

“…For TS2, the maximum stress was 5.27 MPa, whereas the maximum reached 10.49 MPa in TS4. In general, the stress amplitude and PGA should present an approximately linear increase (Xie et al, 2019a). However, the stress response of the wall bushing with FRSDs in this experiment was dramatically reduced under strong ground motion input, confirming the effective energy dissipation of the energy dissipation device.…”

“…The seismic performance of wall bushings is therefore of serious concern and requires further study. The seismic performance of an 800 kV wall bushing was previously evaluated by adopting a full-scale model specimen fabricated based on an actual commercial wall bushing, as shown in Figure 1 (Xie et al, 2019a). The test results demonstrated that the maximum stress along the bottom cross section of the wall bushing specimen was larger than the threshold allowed by Chinese standard GB 50260 (Ministry of Housing Urban-Rural Development (MOHURD), 2013), indicating its inadequate seismic performance.…”

“…The test results demonstrated that the maximum stress along the bottom cross section of the wall bushing specimen was larger than the threshold allowed by Chinese standard GB 50260 (Ministry of Housing Urban-Rural Development (MOHURD), 2013), indicating its inadequate seismic performance. More details regarding the previous model experiment can be found in Xie et al (2019a).…”

Seismic performance of UHV composite post electrical equipment interconnected using a rigid bus with a sliding fitting

“…porcelain and composite materials; Khalvati et al, 2011;Moustafa and Mosalam, 2016). In addition, the UHV electrical equipment is higher, more massive, and slenderer than the counterpart service operating under a lower voltage (He et al, 2019a(He et al, , 2021Xie et al, 2019a). These physical characteristics make the UHV electrical equipment more vulnerable during earthquakes.…”