CASCADE CURRENT TRANSFORMER Russian patent published in 2005 - IPC

FIELD: electrical engineering.

SUBSTANCE: connected to low-voltage metering winding of in-service current transformer is primary winding of additional current transformer with transformer ratio equal to unity so that cascade current transformer is formed, its measurement error being equal to sum of errors of in-service transformer and additional transformer whose error throughout entire range of loads connected to its secondary winding is approximately equal in absolute value to that of in-service current transformer and its polarity is reverse to that of error of in-service current transformer. Additional current transformer has magnetic circuit, primary winding, and secondary winding; its magnetic circuit is assembled of several cores wound of ferromagnetic ribbon and inserted into each other or placed one on top of other and separated by nonmagnetic gaskets. Secondary winding is wound on magnetic circuit assembled of several cores so that part of secondary winding turns passed through holes in nonmagnetic gaskets enclose at least one core.

EFFECT: enhanced measurement accuracy of in-service current transformer.

3 cl, 1 dwg