A short circuit in the electrical cables with polymer insulation: a new look at the cause of its occurrence and non-traditional ways of solving the problem

TL;DR

This paper investigates how thermal aging causes abnormal conductivity in PVC insulation, leading to short circuits, and proposes preventive measures to reduce fire hazards caused by this phenomenon.

Contribution

It reveals that thermal aging can induce a spontaneous transition of PVC from insulator to conductor, offering a new understanding of short circuit causes in polymer insulation.

Findings

Thermal aging causes PVC to exhibit abnormal high conductivity.

Transition from dielectric to conductive state in PVC is spontaneous and uncontrollable.

Preventive measures can significantly reduce fire hazards from short circuits.

Abstract

It is known that most of the electrical cables use as insulation compositions based on polyvinyl chloride. Like most polymers, the latter is quite sensitive to thermal aging, which is not without reason, to be one of the main causes of the various types of faults in the polymeric insulation, leading eventually to a short circuit and fire. On the example of the most common polymer insulator-PVC subjected to preliminary partial thermolysis, simulating the process of accelerated aging, we for the first time show that in this case as a result of the aging process, the electrical conductivity of PVC can acquire abnormal (not obeying Ohm's law) character. In this case, transitions from a state with normal (low) conductivity of PVC into the state with an ab-normally high conductivity was clearly observed, being spontaneous uncontrollable process. Es-pecially the large-scale nature of these changes allowing easily transferring polyvinylchloride from a state of typical dielectric (insulator) in a class of conductors attracts attention.). Thus, an-other one of the most important features of a short circuit in the PVC insulation is opened. It is noted that the reduction of fire hazards in this case (by the maximum possible elimination of the phenomenon of short circuit due to thermal aging of polymeric insulation) should be preventive in nature, as the most effective, simple and convenient way.