| Vacuum switchgear internal overheating problem frequently occurred in the process of the use of the switch cabinet,causing temperature fault,seriously affect the security and stability of switchgear running,and the waste of electricity.This paper uses the memory alloy high damping and prestrain constraint condition,applying of memory alloy material tablet to improve the vicious cycle problem of contact resistance and local heating in vacuum switchgear,improving the safety of switchgear running reliable,saving electric energy,has great engineering application value.The main research content of this paper is as follows:Firstly,Research on the memory alloy tablet mechanism of high damping and restoring force characteristics.The influence of the amplitude,prestrain and frequency in memory alloy damping is analyzed,found the memory alloy under different prestrain,amplitude and frequency damping data is different.Measured the prestrain constraint condition memory alloy pressure piece of restoring force in the process of heating up,analysising the restoring force data,founded the memory alloy tabletting restoring force growth rate with the increasing of prestrain by analysis the restoring force data.At the same time,for the memory alloy tablet repeated heating and cooling process,explored the thermal cycling effect on memory alloy tablet restoring force,the influence of deformation recovery limited memory alloy tablet were produced when restoring force through will not go away after several thermal cycling.Secondly,Studying the dynamic and static contact contact resistance change of applied the memory alloy tablet of 12kV1250 A circuit breaker under different running environment.The best piece of number and the optimal installation location of memory alloy tablet was determined by the experimental study,and then on this basis,respectively,to study the contact resistance changes and contact temperature changesof installing the common tablet and memory alloy tablet dynamic contact insertion depth difference and the data of the circuit breaker dynamic contact contact resistance under different humidity conditions.The results show that the temperature rise of the contacts can be reduced by 4.1 ℃,and the contact resistance can be reduced by2.44μΩ when the memory alloy is used.Thirdly,Obtaining the damping data of the memory alloy tablet with different initial prestrain under different vibration amplitude by experimental study,summarized the damping changing laws with the amplitude changing by analysize data.According to the Logistic model for nonlinear regression model using least square method to iterative fitting of damping and amplitude,the function relation between the damping-amplitude model is established.At the same time,measuring the contact resistance under different damping values,the contact resistance-damping model is established for damping-amplitude model is verified.Finally,Memory alloy tablet be applied in 12kV1250 A metal enclosed vacuum switchgear breaker in the contact pressure reed of plum,through constructing test platform measured the contact temperature of dynamic and static contact of using common spring steel tablet and memory alloy tablet under the same operating conditions,found the stability of the temperature of the static contact and moving contact,the arm of the circuit breaker of using memory alloy tablet than the ordinary spring steel materials were reduced 2.5 ℃,2.1 ℃ and 2.5 ℃.Respectively,to the switchgear for only B phase using the memory alloy tablet and three-phase adopts the memory alloy tablet for the whole cabinet temperature rise test,the highest temperature rise test temperature decreased by 2.4 ℃ and 4.3 ℃,it verified the safety and energy saving of memory alloy tablet be applied in 12kV1250 A metal enclosed vacuum switchgear breaker reed plum contact. |
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