Some specific questions of Insulation coordination in Mediterranean and subtropical regions

摘要

Asset management of high voltage networks situated in some specific world’s regions includesparticular precautions in application of complex discipline of Insulation coordination. Discussedregions include narrow ring around Mediterranean Sea and areas with similar, mostly subtropicsclimate. They are basically characterized by very high parameter of equivalent salt salinity (ESDD)arising from nearby sea (e.g. in Adriatic region) or even from desert sand (e.g. in Maghreb region).What is specific for Mediterranean type of insulation pollution is high level of NSDD parameter due tolimestone kind of sea bed. Further to that such areas are characterized by high level of lightningactivity, strong winds and relatively high humidity and temperatures. As the consequence of it thespecific end-of-life failure modes of external high voltage insulation are appearing and particularprecautions in design and in maintenance phase are demanded. Some experiences will with thecomposite insulators built-in in high voltage networks in these regions will be shown.One of important question is the dependence of great summer fires in countries like Spain, Greece orCroatia to Insulation coordination and generally on behaviour of great electric power systems. Besidesnatural wildfires it is mentioned kind of fires intentionally caused in great cane farms in countries likeBrazil, South Africa or Australia. It is not still recognized that insufficient solutions in Insulationcoordination for high voltage lines exposed to various kind of great fires is one of the key factor ofgreat blackouts in many countries. Therefore the study of interactions of “fire-lines” is necessary inboth methods: in laboratory tests and in on-site experiments. Some results will are summarized fromstudies and operational experiences in Croatia and some other countries from distribution andtransmission networks.