Thermoplastic high performance cable insulation systems for flexible system operation

Crosslinked polyethylene (XLPE) has been the cable insulation material of choice in many different transmission and distribution applications for many years and, while this material has many desirable characteristics, its thermo-mechanical properties have consequences for both continuous and emergency cable ratings which, in turn, have implications for system operational flexibility. In this paper, we describe the principles and two embodiments through which new thermoplastic insulation systems can be actively designed with improved electrical and thermo-mechanical properties for use in cable applications. First, a blend system based upon high density (HDPE) and low density polyethylene (LDPE) is considered, before comparable principles are applied to combinations of polypropylene grades. In both cases, a suitable formulation is first developed through laboratory testing of film and plaque specimens, before a mini-cable is produced and tested.