Research On Seismic Response And Composite Isolation Technology Of UHVDC Disconnector

UHVDC disconnector is a kind of electrical equipment with large structure size,high center of gravity and large horizontal flexibility.Its natural vibration frequency is 1-10 Hz,it is very close to the predominant frequency of seismic wave,and it is easy to produce quasi resonance under earthquake action.The top will produce a large acceleration amplification factor,the root of electrical equipment will produce great stress,and the top of moving column and static column will produce great relative deformation and damage.In this paper,firstly,the field dynamic characteristic test of UHVDC disconnector is carried out,and the finite element model is established with ANSYS finite element software,and the dynamic characteristics are analyzed theoretically.Then,based on the seismic response analysis of UHVDC disconnector under different peak seismic waves,a composite isolation design scheme with friction sliding plate is proposed,and the numerical model of the isolation system of DC disconnector is established.Through the time history analysis of large and small earthquakes of 9 degrees,the advantages and disadvantages of ordinary laminated rubber bearing and parallel viscous fluid damper isolation scheme are pointed out,and the friction is preliminarily analyzed the characteristics of sliding plate parallel composite isolation and the effect of adding friction slide plate in parallel.In the design of parallel composite isolation with friction slide plate,the parallel composite isolation scheme of friction slide plate and ordinary laminated rubber bearing is proposed.The influence of friction coefficient and isolation layer period on seismic response of structure is analyzed through time history calculation.Then,for the parallel composite isolation of friction slide plate and ordinary laminated rubber bearing with small friction coefficient,viscous fluid resistance is added in parallel in order to optimize the isolation effect,the damping ratio of the isolation layer is increased to optimize the isolation effect.The influence of the parameters such as friction coefficient,isolation layer period and damping ratio on the seismic response of the structure is analyzed.Finally,according to the seismic response results and the characteristics of lead rubber bearing,the lead rubber bearing is used to replace the ordinary laminated rubber bearing and viscous fluid damper to form the friction coefficient with small value The results show that the isolation effect is optimized and the influence of mechanical parameters of lead rubber bearing on the seismic response of the structure is analyzed.The conclusions are as follows:(1)As a kind of "high,large,flexible and heavy" structure,the maximum acceleration amplification factor of the top of the structure can reach about 7.70 under the earthquake action,and the top of the moving and static pillars will produce a large displacement.The stress safety factor of the flange connection at the root of the insulator is not enough under the 9th degree rare earthquake,so it is necessary to design the isolation device.(2)The simple friction slide plate base isolation can significantly control the transmission of horizontal shear force to the structure,but the displacement of the isolation layer can not be effectively controlled,so the simple friction plate should not be used alone.(3)For the parallel composite isolation of friction slide plate and ordinary laminated rubber bearing,when the friction coefficient is large,it is not conducive to the reduction of the amplification coefficient of the top acceleration of the structure under large earthquake.When the friction coefficient is small and the period of isolation layer is large,the acceleration amplification coefficient at the top of the structure can be reduced,but it is difficult to control the maximum displacement of the isolation layer under large and small earthquakes.(4)Increasing the damping ratio of the parallel composite isolation layer with friction slide plate and ordinary laminated rubber bearing with smaller friction coefficient will increase the acceleration amplification coefficient at the top to a certain extent,but it can greatly reduce the maximum displacement of isolation layer under large earthquake,but the control effect on the maximum displacement of isolation layer under small earthquake is not as good as that in large earthquake.(5)The results show that the parallel composite isolation composed of lead rubber bearing and friction slide plate with smaller friction coefficient has excellent isolation effect.Through the reasonable combination of parameter values,the maximum displacement of isolation layer can be further reduced when the acceleration amplification coefficient at the top of the structure is small and the same,so that the isolation layer can meet the isolation requirements under small earthquake.