The combination of a machine's rotation cycle and the unpredictable industrial interference encountered by rotating machinery can generate a time-varying noise signal. Such signals cause difficulty while detecting the quench voltage in superconducting rotating machinery. Quench detection is more difficult in high-temperature superconductors (HTS) than in low-temperature superconductors (LTS) because the normal zone propagation (NZP) velocity of HTS is lower than that of LTS. To detect the quench signal in an HTS, signal wires are widely used for voltage taps. However, owing to the low NZP velocity, it is difficult to detect the quench signal in HTS when the voltage taps are attached at short distances from the HTS devices. Furthermore, there is a possibility of the HTS burning out when voltage taps are attached to both ends of the HTS tape, because the hot spot is scarcely dissipative and thermal runaway may occur in the normal zone. Thus, detecting the quench in HTS rotating machinery is difficult. Moreover, the signal wires used in the voltage taps become twisted when the HTS rotor coil rotates to generate magnetic flux. Therefore, in this paper, a sensitive quench-detection method that uses electromagnetically coupled coils is presented for application to HTS rotating machinery.
Bibliographical noteFunding Information:
Manuscript received August 28, 2017; accepted January 23, 2018. Date of publication January 30, 2018; date of current version February 20, 2018. This work was supported in part by the National Research Foundation of Korea grant funded by the Korean Government (MSIP) 2017R1A2B3012208, in part by the “Human Resources Program in Energy Technology” of the Korea Institute of Energy Technology Evaluation and Planning, and in part by the Ministry of Trade, Industry, and Energy, Republic of Korea (20164030201100). (Corresponding author: Tae Kuk Ko.) S. Song and Y. Choi are with the School of Electrical and Electronic Engineering, Yonsei University, Seoul 03722, South Korea.
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All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering