Major blackouts in the development of electricity distribution networks

摘要

Protection against wide-scale blackouts is a crucial part of the management of the modern electricity distribution business. Although the everyday reliability of electricity distribution has been significantly improved by network automation solutions and new construction techniques over the past few decades, the challenge of major storms and long-lasting interruptions still remains. This is the case especially in rural areas where vulnerable aerial lines are typically found. Although major storms may lead to wide-scale blackouts and may cause significant damage to the business, the issue of major blackouts has mostly been neglected in the strategic-level planning of electricity distribution systems. The reason for this is the lack of practically applicable analysis models. Modern distribution management systems usually support traditional reliability calculations, but they do not provide tools to estimate the risk of occurrence and effects of extreme weather events for the electricity distribution business. In this paper, methodology is presented for major storm modeling from the electricity distribution perspective. In the paper, storm and interruption data gathered from electricity distribution utilities are analyzed, and a major storm model is introduced. By the results, the utilities and authorities involved are able to assess the network renovation investments required to avoid long-lasting interruptions caused by major storms. The results are based on a survey commissioned by the Finnish Ministry of Employment and the Economy in 2012. The work has been carried out in cooperation with several Finnish electricity distribution utilities that have experienced wide-scale blackouts as a result of major storms in their electricity networks over the last few years.