Experimental Study On Safety And Energy Saving In 12kv 3150A Vacuum Switchgear Applied Shape Memory Alloy

Overheating problem not only reduces the security and stability of the switchgear, but also wastes energy. Currently, the research for the switchgear overheating problem is mainly concentrated in three areas: switchgear temperature monitoring system, the simulation and analysis of temperature field, and methods to reduce the contact resistance. But for the vicious cycle issues of localized heating and contact resistance in operating is less involved. In this paper, according to the recovery characteristics witch temperature of the pre-deformed shape memory alloy at elevated constraint state, fastening spring and connection gasket of shape memory alloy used in vacuum switchgear will improve the vicious cycle issues of local heating and contact resistance, strengthen the safety of equipment operation and save energy. It is very important in engineering application. The main contents of paper are as follows:Firstly,Research on electrical contact model, the electrical contact temperature and the factors affecting the contact resistance, analyze the restoring force model of the shape memory effect at constrained state, and then research on how to improve safety and save energy through the shape memory effect.Secondly,Get the recovery force data of the pre-deformation shape memory alloy at constraint state. Obtain the variation of restoring force with the temperature at restraint state. According to the Logistic model, fit the regression function of recovery force and temperature by using the least squares method. Also analyze the effect of thermal cycling and pre-deformation on the function and make corrections.Thirdly,Though comparative test, analyze the variation of contact resistance with pressure and temperature by using conventional materials and shape memory alloy materials to electrical contact parts. Draw the conclusion that the shape memory effect can reduce the contact resistance. The highest drop of contact resistance are 85% and 45% respectively by using shape memory alloy gasket and spring to the contact part of copper bus-bar joints and tulip contact. In the case of copper bus-bar joints, Select the pressure and temperature as independent variables of contact resistance, and fit the regression function of contact resistance. Get the function of contact resistance about press and temperature by using shape memory alloy gasket to copper bus-bar joint.Finally,Through the temperature rise test of the individual contact part and the entire cabinet applied shape memory alloy, get the data of electrical contact temperature using ordinary materials and shape memory alloy materials. Make the conclusion that the temperature of contact part by using shape memory alloy is lower than the ordinary materials in different degrees. The highest drop of temperature are 6.5℃, 5.9 an℃ d 2.3 ℃respectively in the temperature rise test of copper bus-bar joints, tulip contact and the entire cabinet. It proves the safety and energy saving by using shape memory alloy to 12 k V 3150 A switchgear electrical connection part.