| In the power system,the cable plays a role in reliably transmitting power and safely connecting the substations and the subscribers.At present,the cable joints mainly adopt the processes of twisted connection,hydraulic tight connection,and welded connection.These conventional processes often consume a lot of manpower,and there are problems such as uneven force at the joint and insufficient tightness.This can result in large contact resistance at the cable connection,uneven distribution electric field,and insufficient stress.Long-term operation,there is a problem of excessive heat generation at the joint,local insulation damage or even disconnection,which will seriously affect the safe operation of the power system,causing huge losses to the user and the power grid.A plastic forming method in electromagnetic forming is a solid phase joining technique.It has many advantages over traditional processes.First of all,it can be used not only for the same metal connection,but also for dissimilar metals and even metal and non-metal connections.Secondly,the forming process is completed in microseconds,with high production efficiency and no dust,green and environmentally friendly;The discharge energy of the forming process can be precisely controlled,reproducible,easy to mechanize and automate,and the joint strength is higher than the conventional process.However,the existing electromagnetic forming devices often use a gas switch as a main switch,and have problems such as short service life and reliable triggering.In order to realize high-reliability cable connection,this paper proposes a RSD based electromagnetic forming device to apply it to the crimping of cable joints to improve the existing cable joint connection process.This paper first introduces the theoretical knowledge of electromagnetic forming and the research status at home and abroad,and briefly analyzes the basic principle of crimping,and derives the calculation formula of deformation of metal parts during the connection process.Then,construct and analyze the circuit structure by PSpice system.The main factors affecting the peak value and front edge of the pulse current are analyzed.Secondly,through the analysis of the deformation process of the pipe fittings,the parameter values of the crimping of different types of cables are calculated,and the electric field,magnetic field,temperature field and elastic plastic force field are established by using COMSOL.Multi-physics coupling model,depicting the process of deformation of different types of cables in the forming coil and the changes in physical quantities.Then,select the key components and equipment in the device,and design the triggering system and forming of the switch Coil.The different types of distribution cable crimping forming experiments are carried out on the built-up device,and the reliability of theoretical calculation and simulation research is analyzed through experiments.Finally,the performance of the cable joint is tested and compared with the traditionally connected joint.Finally,an electromagnetic forming equipment with a voltage of 10 kV and an energy storage capacity of 6.75 kJ was developed.The low-voltage distribution cable was crimped and tested,and a high-reliability cable joint was obtained,and the performance was compared with the conventional hydraulic cable joint.The results show that the cable joints obtained by electromagnetic crimping have better performance in terms of tensile strength and contact resistance than conventional joints. |
