Drain plugs are found at numerous locations on a transformer. The most common locations are on the bottom of radiator banks and tap changer compartments. If additional tightening does not stop these common thread leaks (Figure 1), then the plug has to be removed and repaired which entails draining the oil from the radiator bank or compartment. Again, this results in oil processing and down time for the transformer.
TDS Repair Technique
TDS’s repair procedure is to enclose the leaking plug with a designed aluminum enclosure (Figure 2). TDS technicians inventory various size enclosures to fit the most common drain plugs. The enclosure is held in place by two set screws and crunch teeth that are located on the inside diameter of the enclosure’s bore. Once installed the enclosure’s void is pumped with TDS’s rubber based, non-adhering sealant, thereby fixing the leak. As long as the customer wants the leak stopped, the enclosure remains in place. If the customer wants to access the plug, the enclosure can be removed easily. The set screws are loosened and the enclosure tapped off with a rubber mallet.