Patent ID: 9008982
Filing Date: 2015-04-14
Classification: G01R

Abstract:
1. A method for determining the magnetic flux in a power transformer, comprising: determining a first current through a primary capacitive assembly, the primary capacitive assembly positioned between a phase line and a primary winding of a capacitance-coupled voltage transformer (CCVT); determining a second current through an auxiliary capacitive assembly, the auxiliary capacitive assembly positioned between the primary capacitive assembly and a reference line; calculating a voltage on the phase line using the first current, the second current, the known capacitance of the primary capacitive assembly, and the known capacitance of the auxiliary capacitive assembly; integrating the calculated voltage on the phase line to determine the magnetic flux within a core of a power transformer; detecting that the power transformer has been de-energized; and adjusting the interval of integration based on when the power transformer was de-energized in order to calculate a residual magnetic flux in the core of the de-energized power transformer.