Insulation coordination of MV power cables

In medium voltage power cables, the concept of cost/reliability has been cu rrent since the end of the 1980s when the Brazilian Standards introduced et hylene-propylene-rubber (EPR) insulated cables, with different thicknesses of insulation for conventional cables and for those with blocked conductors or with water tightness constructions. However, despite the benefits obtainable by use of such cables, they have h ad limited use by electrical power utilities, perhaps because the concept h as not become widely recognized. This paper intends to clarify and submit a new approach for design the diel ectric system of medium voltage cables, for use in underground and insulate d overhead distribution feeders. Theoretical aspects of sizing the dielectric system, by means of coordinati ng the insulation, and also using reliability parameters, will be dealt wit h herein. Results of practical applications are also presented and discusse d.