Title:  Study on Series Faults in High-Temperature Superconducting Power Cables

Committee: 

Dr. Graber, Advisor       

Dr. Grijalva, Chair

Dr. Saeedifard

Dr. Pamidi

Abstract: The objective of the proposed research is to further the fundamental understanding of series fault in the high-temperature superconducting (HTS) DC power cable, especially the electromechanical response under the physical stresses of the lap joint of the HTS power cable in the cryogenic environment. For the preliminary work, in order to verify whether the series fault can be detected, a novel method to detect series faults in multi-strand HTS power cables, based on monitoring the transmission characteristics as an indirect way to detect the magnetic signature, is reported. The efficacy of the non-destructive detection method was studied using finite element analysis (FEA) and scattering parameters (S-parameters) measurements on a model cable with a varying number of disconnected strands. Upon the preliminary work, the design and build-up work for the experimental set-up will be performed to analyze the joint failure mode. The extent of joint failure as a function of the joint section area, the solder material, temperature, conductor material, and tensile load, including vibration, will be quantified. The results from the experiment are expected to test failure fatigue models developed to estimate the degree of the failure. Scanning Electron Microscopy (SEM), which scans samples with an electron beam to produce a magnified image for analysis, is also included in order to analyze occurrences of sliding and peeling as well as damage to the superconducting layer. The insights into series faults and joint failure analysis will be applied to build the more reliable HTS DC power cable for MVDC shipboard power systems.