The EGAT High Current Detector (EGAT HCD) is an owned-development invention by Electricity Generating Authority of Thailand (EGAT) and was obtained the Petty Patent from the Department of Intellectual Property, the agency in intellectual property protection of Thailand. The EGAT HCD was originally invented for analysis of unsymmetrical current flowed in four-paralleled stator winding of 2x282 MVA pump storage synchronous machines. The non-homogeneous temperature distribution in the stator windings was found to be main root cause of serious burning in the both synchronous machines. The partial high temperature was generated in their two branches of stator winding. The remedy required clearly conclusion of the Root Cause Failure Analysis (RCFA).