Protection Research And Monitoring System Design Of HTS Binary Current Lead Based On YBCO

Superconducting technology application in power system has already entered the demonstration experiment stage, part of products have also begun to industrialization, but the superconducting technology wants to be really enter the electricity market is facing many problems, among them, the assessment and reduce the operating cost are two major issues need to be resolved. HTS binary current lead as a connecting link of superconducting devices and conventional power, compared with a current lead can reduce the heat leakage of the cryogenic system. To ensure the HTS binary current lead in the safe and stable operation of the power system, especially under the impact of system fault conditions, it is very necessary for the quench protection and monitoring of current lead in order to prevent against the devices and system.This paper firstly describes the typical structure and heat transfer analysis of binary current lead, and mathematical modeling of steady process and transient process, determining boundary conditions, providing a numerical calculation method of heat flow and simulating.Under the HTS binary current lead of quench protection requirements, priority over current protective measures under the impact. Analyzes the structure of the YBCO coating conductor, simulates the relationship between temperature and time of the superconducting current lead under the impact of over-current through MATLAB software and in superconducting tapes made of copper layer on the additional compensation, so that it can withstand the impact of the current 25kA@ 1s, and based on this, proposed using copper wire instead of copper layer, the simulation and related experiments proved that the copper wire can increase security margins and reduce fuses leak hot under the premise of does not change the shunt current.In order to prevent the circuit breakers cutting off current lead non-selectively, and improve the stability of system, this paper proposes a hierarchical protection strategy based on the current amount of binary superconducting current lead, analyzed and calculated the current of each layer setting value, the maximum temperature limit and so on.Based on the hierarchical protection strategy, this paper puts forward a set of complete HTS binary current lead monitoring protection system overall design scheme. In this paper, the monitor method and design parameter of non-electrical quantity parameters, such as temperature, flow rate, and pressure are discussed respectively. The monitor program was developed by the software of LabVIEW, in order to achieve measurement date acquisition, display and storage. Finally, verify the feasibility of the monitoring system and the copper protection measures through the related experiments of current lead.