Horatio Rodrigo

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Gaseous helium at high pressure is regarded as a potential coolant for superconducting cables. The dielectric aspects of cryogenic helium gas are both complex and demanding. In this experimental study, we looked at the interface between a smooth epoxy surface and high pressure helium gas in a homogeneous electric field. The ac flashover voltages of epoxy(More)
Successful validation of the dielectric design of high temperature superconducting DC cables cooled with pressurized helium gas circulation is reported. The dielectric design features were developed based on the tests of several short sample cables. The features were adapted for the dielectric design of the cable and termination components such as high(More)
A valuable solution to the voltage rating limitation of gaseous helium (GHe) cooled HTS power devices is demonstrated through the use of cryogenic gaseous mixtures of small mol&#x0025; of gaseous hydrogen (H<sub>2</sub>) balanced with GHe. An 80&#x0025; enhancement of the dielectric strength, both in dc and ac, is observed for the mixture with 4 mol&#x0025;(More)
The results of experimental determination of surface flashover breakdown voltage under high voltage ac and dc for cylindrical G10 are presented. The results are analysed using Weibull statistics and are compared with theoretical field calculations obtained using Ansoft, which is a software package based on finite element analysis. The results show that(More)
A new and novel design concept for superconducting cables that uses the gaseous cryogen as the dielectric medium is presented. This novel design addresses the challenges in developing a dielectric design of a superconducting cable that is cooled by a gaseous cryogen such as gaseous helium (GHe). This design has the added benefit of improving thermal aspects(More)
An improved model for the estimation of the breakdown voltages of gas mixtures is developed. The application and utility of the model is demonstrated by using it in estimating the breakdown voltages of gas mixtures containing helium and hydrogen that are being developed as an alternative cryogenic insulation and cooling media for certain high temperature(More)
The occurrence of partial discharge is one of the challenges that limit the design options and voltage ratings of gaseous helium cooled high temperature superconducting (HTS) cables. The measurements of partial discharge inception voltage (PDIV) at cryogenic temperatures on several model cables were used in the optimization of the dielectric design of a 30(More)
This paper presents a model to simulate electrical trees in dielectric materials. The model accounts for the characteristic tree patterns and the partial discharges associated with the propagation of trees. This simulation model is used as basis to develop a diagnostic tool to determine the remaining life of insulation materials by relating the fractal(More)
A comparative study of cryogenic dielectric and mechanical characteristics of electrical insulation materials is described. Breakdown strengths and tensile strengths of Cryoflex, Kapton, PPLP, and Teflon were measured at 77 K in liquid nitrogen. Breakdown strengths of Cryoflex, Kapton, PPLP were also measured in gaseous helium at 2 MPa and 77 K. The(More)
This paper explores various power cable challenges for notional electric ship applications including future technology trends for shipboard power cables. To meet the demands of an &#x201C;all electric ship,&#x201D; the cabling requirements of the design are not a trivial issue which can result in significant error in estimating final size, weight, and cost(More)