Experimental Study On Seismic And Shock Absorption Per-Formance Of Electric Porcelain Circuit Breaker Structures

As an important hub of lifeline engineering,the destruction of electric ceramic circuit breaker will directly lead to the paralysis of the whole power system network,unable to meet the needs of people's production and life and the development of disaster relief work,thus further increasing economic losses.Therefore,it is particularly important to maintain the normal,safe and stable operation of the power system.However,the structure of electric ceramic circuit breaker is easy to be destroyed under earthquake due to its structural layout and dynamic characteristics.A large number of earthquake disasters at home and abroad also show that the damage of electric ceramic circuit breakers under strong earthquakes is very serious,which brings tremendous difficulties for earthquake relief and post-disaster reconstruction.Therefore,it is of great significance and value to study the seismic performance of electric ceramic circuit breaker structure.In this paper,LW11-252/Q(vertical)and LW15A-363/Y(T)circuit breaker structures in practical engineering are taken as research objects.The seismic and shock absorption performance tests of LW11-252/Q circuit breaker in type II site and LW15A-363/Y circuit breaker in type I and III site are carried out respectively.A finite element model is established and the test results are limited.The meta-structure is compared and analyzed to verify the validity of the modeling.The main work is as follows:(1)According to the similarity theory,two kinds of circuit breakers,LW11-252/Q(vertical type)and LW15A-363/Y(T type),are designed and 1:5 test models are processed.Based on the analysis of structural dynamic characteristics,combined with seismic grouping,site type,power spectrum and response spectrum,El-centro wave and Chi-Chi wave of Taiwan under typical site condition of type II are selected for the "vertical" system,and an artificial wave is fitted according to the site Tg.The Landers wave,Kocaeli-Turkey wave and the Chi-Chi wave and Darfiled-New Zealand wave of Taiwan under the condition of type I and the typical type III field are tested.(2)The shock absorber was designed and manufactured,and the mechanical properties of the energy dissipating material Ni-Ti SAM wire in the shock absorber were tested.The constitutive properties of SAM wire with diameters of 0.5mm,0.8mm,1.0mm and 1.2mm were tested.The test results show that the stress-strain curve of SMA wires becomes fuller and more energy-consuming with the increase of the strain amplitude of SMA wires.After comparative analysis and calculation,the Ni-Ti SMA wire with a diameter of 1.0 mm is finally selected for the shock absorber.(3)Shaking table tests under various working conditions were carried out on the models of two types of Electroceramics circuit breakers,i.e."vertical" and "T".Before the test,two kinds of circuit breaker models are scanned by white noise to obtain the natural frequency and damping ratio.Then the seismic waves of the above three types of sites withthe peak acceleration of 140 gal,220 gal,400 gal,600 gal and 800 gal are input to the "vertical" structural system,and the seismic waves of the above two types of sites with the peak acceleration of 140 gal,220 gal,400 gal,600 gal and 800 gal are input to the "T" structural system,respectively.Acceleration responses of key parts of two kinds of circuit breaker structure test models under different working conditions were measured,and the test results under different working conditions were analyzed.The weak parts of structural seismic damage and the general rules of seismic performance were found out.(4)The shock absorber is installed on the model of "vertical" and "T" electric porcelain circuit breaker respectively,and the shaking table test is carried out under multiple working conditions.Similarly,three types of Site-Type seismic waves with peak acceleration of 140 gal,220 gal,400 gal,600 gal and 800 gal are input to the "vertical" structure system,and two types of Site-Type seismic waves with peak acceleration of 140 gal,220 gal,400 gal,600 gal and 800 gal are input to the "T" structure system respectively.In order to verify the damping effect of the shock absorber,two kinds of test structures with and without shock absorber are compared.The study shows that the greater the input of ground motion,the more obvious the effect of vibration reduction.When the peak acceleration records of 800 gal are input,the maximum acceleration damping rates of the "vertical" and "T" structural systems are about 33.4% and 28.63% respectively.And the damping device is more obvious for the displacement of the structural system,which proves that the shock absorber is reliable.(5)Finite element modeling and dynamic time history analysis of the above two kinds of circuit breaker test model structures are carried out by using ABAQUS finite element analysis software,and the results are compared with the results of shaking table test.The results show that the acceleration response and displacement response of the model structure under various working conditions are in good agreement with the analysis results,which shows that the finite model adopted in this paper is effective and reliable.In this paper,the prototypes of LW11-252/Q(vertical)and LW15A-363/Y(T)circuit breakers are established by using finite element software,and the finite element analysis of the horizontal seismic stresses of the prototypes of the two kinds of circuit breakers before and after installation of shock absorbers is carried out.The earthquake effect is obvious.