Last week, we talked about the importance of properly testing a newly installed transformer. Particularly, we discussed the need to take and analyze DGA samples according to a recommended schedule during at least the first month of service. It is equally important to perform the first routine, in-service monitoring and diagnostic tests according to a recommended interval. We refer to that as the “Ten-Month Full-Oil Test”. The timing is important, as some defects may provide initial symptoms during this period without causing revealing more obvious indication until after the warranty period has expired. The timing of the first interval at ten months, and running the complete recommended package of tests, will serve to establish a diagnostic baseline. In addition, the results, particularly abnormal DGA results, may be used to start a dialog with the manufacturer if problems or defects are suspected.
Responsible transformer owners perform annual testing of insulating liquid. Using this initial ten month interval, followed by annual testing, allows you the opportunity to have current oil test results about two months before the warranty expires. This allows you to bring up with the manufacturer any abnormalities you might find in a timely fashion, so that any difficulties that may arise can be addressed in a satisfactory fashion.
