| The power system is an integral part of the lifeline project,lightning arrester as the protector of the power system,the stable operation of the power system is inseparable from it,according to the experience of many earthquake damage,lightning arrester due to its low strength material characteristics and high and soft pillar type structure form,the proportion of damage after the earthquake is very high,Tangshan earthquake lightning arrester damage rate of up to 66%,the damage of individual electrical equipment is likely to cause a large area The damage to individual electrical equipment is likely to cause a large area of the power system paralysis,seriously affecting the postdisaster reconstruction work and the order of life of the victims.In order to improve the disaster resistance of such earthquake-prone equipment as lightning arrester,this paper carried out tests and combined with finite element analysis for the prototype structure of420 k V lightning arrester,and studied the general law of earthquake resistance and isolation performance of lightning arrester equipment to provide the basis for its practical application,the main work is as follows:(1)Shaking table tests were carried out on the prototype structure of 420 k V surge arrester.The seismic performance of the equipment under artificial wave ground vibration input was studied,and the results showed that the 420 k V arrester can meet the seismic requirements of its high design level ZPA=0.5g;the initial self-oscillation frequency and damping ratio of the equipment in X,Y and Z directions are2.13Hz/2.6%,2.13Hz/2.6% and 67.14Hz/0.55%,which are easy to resonate;the acceleration and displacement of the top of the equipment The acceleration and displacement at the top of the equipment are more obvious,with peak acceleration of4.96 g and peak displacement of 133 mm under the test condition;the stress and strain at the bottom of the first layer of casing are larger,with peak strain of 350uε under the test condition,and the safety factor is smaller,which is a vulnerable part of the equipment.(2)ABAQUS software is used for finite element analysis of the arrester equipment.The test and finite element analysis results are consistent with the law,the relative error is within 11%,the finite element analysis results are reasonable.Arrestor structure under the action of artificial wave ground vibration response is the largest,El-Centro wave followed by the smallest JY wave.0.6g artificial wave + wind load conditions,the safety factor of the key parts of the arrester is 1.74,less than 2.0,does not meet the IEEE specifications,0.7g artificial wave + wind load conditions,the bottom of the equipment layer of casing safety factor of 1.49,has been less than our specification requirements.Coupling model in the arrester equipment ground vibration response compared to the single arrester equipment are a certain degree of amplification,acceleration,displacement and strain peak values appear in the vertical span ratio of10% of the working conditions,the coupling effect is the most obvious,with the increase of the vertical span ratio,the ground vibration response shows a trend of first decrease and then increase,when the vertical span ratio in 20%,the ground vibration response is the smallest,the best seismic performance.(3)The seismic isolation study of the arrester equipment by test and finite element analysis.The results show that the ALJ-81 wire rope shock absorber becomes a symmetric hysteresis curve,and the ALJ-82 wire rope shock absorber becomes an asymmetric hysteresis curve.The hysteresis curve of the wire rope shock absorber is fitted and calculated by using the one-dimensional hysteresis index model,and the hysteresis curve under cyclic loading and variable loading amplitude is simulated numerically by matlab program with reference to the calculation results.The frequency of the arrester is significantly reduced compared with the original model,indicating that the overall stiffness of the isolated model is reduced.The reduction rate of acceleration response of the equipment after isolation is about 42.42%,and the reduction rate of strain response is about 35.61%,but the increase rate of displacement response is about25.38%.The lower the stiffness of the wire rope isolation device,the better the isolation effect,but the displacement response of the upper structure will also increase.Under the action of 0.5g seismic wave alone,the maximum stress in the vulnerable part of the seismic isolation model did not exceed its damage stress,and the minimum value of safety factor was 3.6,which satisfied the code requirements.Under the joint action of wind load and earthquake,the Mises stress of key components of the isolated model decreased compared with that of the original model,and the safety factor increased.Even under the strong disaster condition of 0.7g artificial wave + wind load,which the original model cannot withstand,the minimum safety factor of the isolated model is still2.07,which meets the code requirements and the disaster resistance performance is obviously improved. |
