Cost of outages

Outages can cause extensive economic damage to customers receiving a supply of electricity due to drops in production, spoilt raw materials, damaged equipment etc. Outage frequency and duration can be reduced by technical means, but this usually requires high investment levels related to the power distribution and generation system. When planning a power system a compromise must be reached regarding reliability and outage costs. As a basis for this planning process up-to-date knowledge of customers outage costs is necessary. The study focuses on conditions in low and medium voltage distribution networks. 28 distribution companies participated in the survey, 6 in Denmark, 18 in Finland and 4 in Iceland. The customer categories and corresponding number of customers were: residential sector - 9794, agricultural sector - 1404, industrial sector - 570, commercial sector - 599 and the public sector - 577. Costs of outages of various duration from 1 to 8 hours were assessed assuming that these breaks in electricity supply occurred during normal business hours. Voltage dips and and sequences of short, repetititive outages were also considered. The main method of research was customer survey. The results are presented in detail. (AB) (35 refs.)