A complex current ratio device for the calibration of current transformer test sets.

A practical method with high accuracy in generation and a pplication of error values for calibration of curre nt transformer test sets is described. A PC-controlled three-phase power source with a standard wattmeter is use d for generating the nominal and error test currents while an electronically compensated current comparator is used to provide summation and subtraction of them, p recisely. With this method, any ratio error and pha se displacement values could be generated automaticall y and nominal and test currents could be grounded o n the test set safely. Because of its high accurate ratio and phase error generating capability, any type of test set regardless of its operating principles could be cal ibrated.