V6.230 20131017916 Dual Algorithm LTC Condition MonitoringThe TTC-1000 has several set points that the user can employ for LTCconditioning monitoring. The LTC differential is the mathematical differencebetween the probe named LTCDIFF, LTCDIFF1, LTCDIFF2, LTCTANK,SELTANK or DIVTANK and top oil temperature. Therefore is only available inunits with more than one temperature probe. For instance, if P1 is used for TopOil, P2 for Ambient, a third probe would need to be available for LTC monitoringof one tap changer tank. Should the transformer have two tap changer tanks,only one probe would be available for other functions such as Top Oil.There are two heating events that can be detected with the TTC-1000: Slowly evolving Problems normally associated with coking of the tapchanger contacts Quickly evolving problems associated with a malfunction of the tapchanger mechanism which leads to rapid temperature increases which ifnot caught quickly can lead to catastrophic failure of the transformer.The range of the calculation is from –20 to +20 ºC.NOTES:1. When using LTC condition monitoring, it is important to remember toname one of the probes LTCDIFF, LTCDIF1, LTCDIF2, LTCTANK, SELTANKor DIVTANK. Evaluation of the LTC set point is not done unless one of theprobes is named for that function (LTCDIFF, LTCDIFF1, LTCDIFF2,LTCTANK, SELTANK or DIVTANK).2. LTC differential functions use the first probe named TOP OIL, TOP OIL 1,TOP OIL 2, or TOP OIL 3.
