Study of the viscoelastic behavior of cold-shrinkable joints for MV cables

Abstract

A new technology to joint medium voltage cables has been introduced in recent years: cold-shrinkable joints are gradually replacing premolded slip-on and heat-shrink type products. One of the key concerns on the functioning of such products is about the ability to shrink onto the cable insulation after long periods of storage time. The viscoelastic properties of the materials used in cold-shrinkable joints determine the evolution of the shrinkage behavior with storage conditions and of the pressure on the cable after installation. These material properties were measured. A measuring device was developed to read directly the pressure of the joint on the cable as function of time and it was used to assess the effects of storage and installation conditions.