Study On The Seismic Collapse Capacity Of Large Converter Station Valve Hall Structure With Electric Equipments

With the development of social modernization，needs of the power system is growing,DC transmission system with high transmission stability meets requirements of high-voltage,large capacity and long-distance. In recent years, HVDC converter stations have beenestablished. Since DC transmission system converter stations have built for a few years，seldom earthquake damage and few research are reported, once power system interrupts in theearthquake，it brings heavy disaster and incalculable economic losses. To slove aboveproblems, shaking table tests and seismic performance of large-scale converter station valvehall structure with electrical equipment was analyzed, through establishing seismic fragilitycurves of valve hall structure using incremental dynamic analysis (IDA), the seismicreliability of valve hall structure is evaluated. The main works and conclusions are as follow：(1) Converter station valve hall structure with electrical equipment was studied, thespecimen for shaking table test consists of three l/15scale frames valve hall isdesigned.Seismic response of the valve hall structure with and without the suspensionequipment were compared, seismic response of valve hall and damage formwere studied. Thetest results show that the influence of suspended valves to valve halls is low. Displacementand acceleration response of valve hall structure and suspension under horizontal seismicaction is greater than under vertical seismic action; valve hall structure began to enter theplastic stage under7degrees middle earthquakes.(2) The comparison between the nonlinear numerical model of test model and testresults was carried out. Results show that the nonlinear numerical model is feasible andreasonable. Based on elastic-plastic analysis of the valve hall structure, torsion effects of thevalve hall structure under longitudinal earthquake actions is found, structural optimizationdesigns were carried out, seismic responses of the original structure model and optimizedstructural model under2D earthquake actions were compared. Results show the displacementdifference can be decreased by the structural optimization designs.(3) Based on the nonlinear dynamic time history analysis results under earthquakeactions and the characteristics of the suspension equipment, the calculation model ofsuspension equipment under the earthquake effect was established and the simplifiedcalculation method was proposed. According to seismic performance levels， siteclassification，classification of design earthquake，the seismic response of suspension isobtained by simplified calculation method. (4)Seismic fragility curves and formulation of valve hall structure were establishedemploying IDA to evaluate the seismic reliability of valve hall structure. Results showexceeding probability of collapse damage of the valve hall increases fast with the increase ofthe peak ground acceleration; when peak ground acceleration reaches1.5g, exceedingprobability of collapse damage is up to95%.(5) Through distribution and development of plastic hinge of valve hall structure,under7degrees (0.15g) rare earthquake, the steel structure is not yet fully yielded, thereinforced concrete section has entered the plastic deformation stage. Bottom of shear walland part of structural columns, beams at both ends has reached its plastic rotation capacity.