Posted By C L Cadet Hello, I am interested in finding out if it is acceptable to top up oil in a high voltage transformer while it is in service (11.8/33kV)

Posted By George Wedgwood Absolutely no way you should consider this activity whilst the transformer system is energised. Removing the filler opening may lead to the Bucholz relay trip being rendered ineffective, if fitted, and if not how would you know that a possible fault would be safely managed? Filling oil is a specialised operation and not one where you would simply climb up on top with a top-up can but it is essential that risks are assessed beforehand in any event. Depending on the type of transformer you may want to consider; Is it a large HV transformer? Is there a leak anywhere that may be causing loss of oil? Has the transformer had any faults that could have caused oil breakdown? What type of oil is required? Is the transformer temperature normal? Has the oil been analysed and are the results good as a dielectric? How will you access the filling point? Have you got a clean oil bowser and relaible delivery system for filling? Have you got the manufacturer's filling and operational instructions? Have you got the correct oil? Can you perform a full isolation of the transformer system, including the low voltage control system? Will you be issuing a permit to work beforehand? Are the sight glasses clean? When was the oil last changed? Is an electrical engineer in charge of the work? Is the filling team equipped with the right PPE? Have you got accidental spill controls available in case of lost oil? There are probably more questions but that will probably do for now. It is essential that the question is asked of a competent electrical person with transformer experience and a plan is agreed before starting but importantly, that the reasons for the requirement are considered carefully as transformer testing may be a better start before filling. Hope this helps, George (Former power station electrical engineer)

Posted By GT George, I am not an ex power station electrical engineer. Sorry to read you have blocked my retort to CLCadet. However, I presume that you feel in your professional capacity as a Moderator, Electrical Engineer, or FCMIOSH allows you this priviledge,and that your reply is more in keeping with the information we as a group should be issueing to someone who doesn't understand high voltage. Am I correct in assuming that the Moderators committe have come to a concensus of opinion that your comments are koshered and acceptible? I would respectfully suggest that you are misguided. If you wish to contact me off forum I will be glad to explain to you why. Not wishing to get into a slanging match but more into a constructive, informative discussion, that helps the uninitiated i.e CLCadet.by name and nature. Please I would also suggest you read the thread question and answer it appropriately. Yes or No. GT