Research On The Technology Of High Current Carrying Capacity DC Disconnector

High current DC disconnector is the key electrical equipment in ITER converter power system,but also plays an irreplaceable role in the electrolytic aluminum and other high energy consumption industry.The key performance of the high current DC disconnector is current-carrying capacity,however the temperature rise in the contact area impose great restrictions on it.The existing DC disconnector often reduces the temperature rise of the switch by increasing the conductor area of the switch,which can lead to excessive switching capacity,resulting in increased maintenance costs for the switch installation and waste of the conductor material..Primary cause of the temperature rise in the disconnector is contact resistance and the current inequality between the contacts.This paper will focus on the key problem of the disconnector,redesign the structure of contacts,improve the current-carrying capacity of the DC disconnector.At first,aiming at the single contact's low current-carrying capacity and the current inequality between the contacts of existing high current DC disconnector,this paper put forward the new type of circular and annular contact structure.New contact's contact form is different from the blade type contact,and equipped with a spring based adaptive structure to ensure its current equality performance.Then,in this paper,a contact characteristic test system is designed,and the contact sample is tested to measure the contact resistance of the contact.Compared with the blade contact,it is verified that the new contact has a smaller contact resistance.The contact resistance characteristics of the new contact are tested,and the performance characteristics of the contacts are mastered by the test results.It is of great significance for the optimal design and practical application of the contacts.The current equality performance of the multi-contact parallel is tested.The test results verify that the current-carrying performance of the new contact structure meets the requirements.Finally,this paper combines the design of DC disconnector in ITER converter power supply system,designs a DC disconnector based on new contact structure.The steady temperature simulation shows that the temperature rise of the disconnector is within the standard limit range.The simulation of the dynamic stability of the disconnector shows that the disconnector can withstand the short-circuit transient.The switch structure simulation and insulation check simulation analysis verify that the structure of the switch meets the structural and insulation level design requirements.