Papers by Vutukuru Vasudeva Rao
IEEE Transactions on Applied Superconductivity
Power Research - A Journal of CPRI
Manufacturing of HTS power cables requires winding the HTS tapes helically around a former. These... more Manufacturing of HTS power cables requires winding the HTS tapes helically around a former. These HTS tapes are costly, and delicate and require sophisticated winding machinery which is expensive. In this paper, an in-house economic mechanism for converting a conventional lathe machine to a Tape Winding Mechanism (TWM) is discussed in detail. In addition to the developed prototype, the technical issues and challenges encountered during the development of TWM are listed. The developed TWM was instrumental in successfully winding 10 HTS tapes simultaneously around a tin-coated braided copper former of 19 mm diameter with a pitch length of 210 mm for a continuous length of 5 m HTS cable. The recommendation of modifying any existing cable winding machine to TWM is also discussed.
Journal of Superconductivity and Novel Magnetism
The Journal of CPRI, Dec 13, 2022
High Temperature Superconductor (HTS) based power cable is a technological marvel which can trans... more High Temperature Superconductor (HTS) based power cable is a technological marvel which can transmit bulk power over large distances without any joule heating as compared to a conventional copper cable, owing to its zero DC resistance in superconducting state. However, to maintain this superconducting state, the cable must be at a temperature below its critical temperature under self-field. Commonly used HTS material includes BSCCO (T c = 110 K) and YBCO (T c = 93 K) and thus, requires cryogenic liquid nitrogen (77 K) for attaining superconductivity. Further, the voltage drops across the various joints such as joint box and current leads in the termination unit must be monitored to ensure optimal operation of the cable. This demands for sophisticated instrumentation operating under extreme low cryogenic temperatures for safe operation, performance monitoring, cryogenic measurements, and control of the HTS power cable cryogenic process. This paper presents the instrumentation scheme followed for testing India's first 6-meter HTS power cable. The instrumentation scheme involves housing of the various temperature sensors and location of voltage tapping, current measurement, cryogen flow measurements, operation of control valves, operation and measurement of high vacuum system, stray field measurement, insulation resistance measurement and dielectric measurements for cable are the important parameters for the successful operation of HTS power cable. To perform data logging NI-DAQ and LabVIEW software was used to develop in-house Supervisory Control and Data Acquisition (SCADA) system. This paper discusses intrinsic aspects of complete instrumentation and developed SCADA system for HTS power cable.
IEEE Transactions on Dielectrics and Electrical Insulation
Power Research - A Journal of CPRI
For the operation of High Temperature Superconducting (HTS) power cables at high voltage levels, ... more For the operation of High Temperature Superconducting (HTS) power cables at high voltage levels, the electric field distribution depends on the relative permittivity of dielectric materials. In HTS cables, PolyPropylene Laminated Paper (PPLP) is used as a cold dielectric material and is wrapped helically along the length of the conductor thereby electrically insulating it. During the installation and maintenance process of HTS cables, termination units and joint boxes, the PPLP is often exposed to moisture. The presence of moisture affects the dielectric breakdown strength and dielectric losses. The effect of moisture content in PPLP at ambient and liquid nitrogen temperature has been studied to determine the breakdown strength, relative permittivity (εr) and dissipation factor (tan δ). Effect of moisture content on the performance of PPLP via the measurement of dielectric breakdown strength and relative permittivity for various temperatures and moisture content are discussed in thi...
2021 IEEE 5th International Conference on Condition Assessment Techniques in Electrical Systems (CATCON)
2021 IEEE 5th International Conference on Condition Assessment Techniques in Electrical Systems (CATCON)
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Papers by Vutukuru Vasudeva Rao