A superconducting
energy pipeline is an integrated system for fuel
delivery and power transmission. In the energy pipeline, direct current
(DC) power is carried by superconducting tapes with almost no loss.
Moreover, liquefied natural gas (LNG) is used not only as one kind
of clean energy but also as a cooling medium. However, the lack of
data on the electrical insulation characteristics of LNG (especially
the resistance to breakdown and flashover) restricts the development
of a superconducting energy pipeline. Therefore, this paper focuses
on solving a series of problems (such as gas tightness, overpressure,
and high voltage) in LNG insulation testing, obtaining the electrical
failure data of multicomponent LNG, and analyzing the behavior of
electric breakdown and flashover in LNG. The test results show that
LNG as a dielectric cooling medium has remarkable performance in withstand
voltage to replace the liquid nitrogen/liquid tetrafluoromethane (LN2/LCF4) binary mixtures. The research could offer
key technical support for the superconducting energy pipeline and
also provide a reference for the study of electrical properties on
other cryogenic fuels.