Studies on the measurement of contact resistance in no-insulation HTS coils

초록

Accurate measurement of contact resistance in no-insulation (NI) high-temperature superconducting (HTS) coils is crucial for their performance evaluation. The sudden discharge test is a widely used method for measuring the contact resistance of NI HTS coils. However, there are several issues regarding the data acquisition system (DAQ) during the test. In particular, the DAQ must operate at a sampling rate exceeding 500 S/s. An infinite impulse response (IIR) filter can introduce a phase delay into the filtered signal compared to the original data. For instance, applying a 4-Hz low-pass Butterworth filter to a high-frequency signal may lead to measurement errors due to this delay. Moreover, remnant field induced by the screening current after the current transportation introduces uncertainty of conducting sudden discharge tests. This paper proposes the qualified settings of DAQ system configuration for sudden discharge test and suggests an alternative method for measuring the contact resistance of NI HTS coils.

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