Dielectric-spectrum-based method and system for detecting PPLP insulation of superconducting cable

Abstract

The invention relates to a dielectric-spectrum-based method and system for detecting PPLP insulation of a superconducting cable. The method comprises: S1, applying excitation voltages at different frequencies to a test sample and calculating an impedance value, complex capacitance and dielectric loss of the test sample under different frequencies by measuring the the voltage and current of the test sample; and S2, acquiring an aging degree of the test sample to obtain an insulation detection result of the sample according to the complex capacitance, the dielectric loss and the corresponding frequency. Compared with the prior art, the method and system have the following advantages: the complex capacitance and dielectric loss of the PPLP are measured and calculated at different frequency points; and on the basis of frequency curve drawing and fitting comparison, the aging degree of the test sample is evaluated and thus the PPLP insulation performance can be detected comprehensively andeffectively.

Description

technical field [0001] The invention relates to the technical field of electric equipment insulation detection, in particular to a dielectric spectrum-based superconducting cable PPLP insulation detection method and system. Background technique [0002] High-temperature superconducting (High-Temperature Superconducting, HTS) cable is a cutting-edge technology, with the characteristics of high current, low loss, and small size, and its transmission capacity is 3 to 5 times that of conventional cables, which can better meet the needs of power energy transmission and urban The demand for power grid construction, but its relevant test and operation experience at home and abroad is very little, and the overall technology is in the stage of network demonstration and a small amount of commercial application on a global scale. The domestic kilometer-level high-temperature superconducting demonstration project in Shanghai is expected to be completed by the end of 2019, but there is n...

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Problems solved by technology

[0003] Obtaining good insulation performance is one of the key links in the practical application of HTS cables. The cable insulation structure is an indispensable part of HTS cables, which can provide the necessary guarantee for the safe operation of superconducting cables. At present, the mainstream insulation structure of HTS cables Liquid nitrogen impregnated PPLP (Polypropylene Laminated Paper, polypropylene laminated paper), PPLP is made of porous pulp material and polypropylene film, and has good impregnation performance. Therefore, the performance of PPLP will directly affect the performance of superconducting cables. Safe operation, the existing superconducting cable insulation testing basically refers to the test items of conventional cables, such as capacitance test, dielectric loss test, etc. However, in the dielectric loss test, there is a lack of relevant testing for the aging degree of PPLP insulation performance

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