A Review of detection and mitigation of negative dissipation factor in high voltage power transformers

This paper provides a review of the various techniques currently used for the detection and mitigation of negative dissipation factor or tan delta in power transformers. Negative tan delta is a serious concern to engineers; its importance is to keep the quality control of the high voltage equipment on a high level. The error happens occasionally, it must be determined whether it is significant to include into the insulation system. Failure to detect and mitigate the error of this nature may result into decreasing dielectric strength, reduced lifespan, and eventually to catastrophic failure of the transformer. This, in turn, will cause external equipment damage, fires and loss of revenue due to the inevitable, consequent unscheduled outage and loss of time in replacing or repairing the apparatus. It also raises a huge concern to the quality product of the manufacturer, which at some point they will lose business to their customers, due to this unresolvable error called negative dissipation factor.