Older oil filled electrical switchgear. Past, present and future

Oil-filled electrical switchgear has been in use both at high and low voltage for many years and has, of necessity, been of robust construction. This fact has led many to assume that it has an indefinite service life. There have been cases of high voltage switchgear installed 70 to 80 years ago still being in service. It is not uncommon to find both high and low voltage switchgear from the 1920s and 1930s still in use. Performance requirements have risen over the years and switchgear technology has developed to meet the challenges. System energy levels have tended to increase as distribution networks have expanded to meet demand for energy which has placed greater requirements on performance. The replacement options for such switchgear are outlined by the author in this paper