Strategy for the renewal of 110 kV substations

Under the impression that there would be high load increases and the target levels of service reliability should be ensured, the German utility Hamburgische Electricitats-Werke AG (HEW) of the city-state of Hamburg constructed a large number of 110 kV substations between 1950 and 1970. Given the specific age structure of the substations and the current state of the electrical equipment in use, HEW has taken advantage of the planned renewal of a large 110 kV substation to develop a strategic approach to the timely evaluation of existing high-voltage plant which also allows long-term maintenance measures to be planned. Future refits will be largely influenced by revised considerations of the company´s philosophy on service reliability, by the inclusion of long-term load forecasts, and by an integrated rolling planning system for the entire 110 kV distribution network. In view of the expected changes and greater competition on the international electrical energy market, the remaining life time of system equipment must be exploited more strongly in order to reduce high investments for the necessary functional substance conservation of the high-voltage power system