Thanks to its excellent properties, such as electrical resistivity, flexibility
and resistance, ethylene-propylene-diene (EPDM) is widely used as an
insulating material for electrical cables. Insulation layers of power cables,
which make up 95% of electrical cables at nuclear power plants, are made
of elastomers. Therefore, normal work can be seriously compromised if
insulation of some cables is easily damaged or degraded. The performance
of electrical cables depends on the physical integrity of the key
components in the insulation layers, because micro-cracks can lead to loss
of insulation characteristics. The use of polymeric materials for the
production of electrical insulation is based on their favorable properties,
which are related to their high stability. Oxidation as a major degradation
process changes the functional characteristics of electrical insulations. The
obtaining of insulating layers of current cables with satisfactory properties
in an electric field were... achieved by a well-chosen formulation consisting
of high performance materials. In this dissertation, a research was carried
out regarding the choice of polymer formulations with EPDM, testing the
crosslinking of the appropriate EPDM formulation using peroxide
compounds in order to slow down the degradation of insulation polymer
layers of medium voltage cables. The proposed EPDM formulations were
examined in terms of degradation, improvement of rheological,
mechanical and electrical performances, and thermal stability. The
possibility of reducing the concentration of zinc oxide in the formulation
with simultaneous improved thermal and electrical stability due to the
adverse impact of zinc oxide on the environment as well as the costeffectiveness
of the insulation process on the cables were investigated. A
new HPLC method that were developed could be used in the cable
industry for routine measurements of percentage peroxide utilization in the
process of making insulating polymer layers of EPDM. The results
obtained showed that the appropriate types and concentrations of
peroxides, as well as the amounts of ethylene in EPDM, can result in the
development of stable insulation of medium voltage cables with excellent
electromechanical efficiency.
