Weather Impact on Components Reliability: A Model for MV Electrical Networks

In order to schedule the choice of maintaining or refurbishing MV equipment, an electrical utility may study ageing effects on different pieces of such equipment. In this paper, the analysis is based on record of outages (MV power cuts) during several years where causes of outages are noticed (and ages of pieces of equipment are also known). Failure rate versus age estimation results are given for different pieces of equipment for MV overhead lines or MV underground cables. We also present quantification of daily weather conditions impact on the reliability of these components. We mainly take into account wind, temperature, humidity, and flashes of lightning intensity. Reliability accelerated life testing models (Eyring or Peck reliability model), have been studied to take into account, impact of temperature and humidity on failures rates of underground MV cable pieces of equipment. Main results on this subject will be presented. Possibilities of using mechanical stress reliability laws (Wolher law, Miner´s Rule or Coffin-Manson law) to model mechanical damages concerning overhead lines components due to weather constraints (wind speed) , will also be discussed in this paper.