Patent ID: 8203814

Claim:
An electrical switching apparatus comprising: a plurality of poles, each of said poles comprising: a conductor, and a Rogowski coil including an opening and an output, said conductor passing through the opening of said Rogowski coil; and a processor circuit comprising: a sensor circuit including a plurality of inputs, each of said inputs being electrically interconnected with the output of the Rogowski coil of a corresponding one of said poles, said sensor circuit further including a number of outputs having a plurality of values, each of said values corresponding to current flowing through the conductor of a corresponding one of said poles, a memory comprising for each of said poles, an offset value for said sensor circuit for a corresponding one of said poles, a gain correction factor for said sensor circuit for a corresponding one of said poles, and a gain correction factor for the Rogowski coil of a corresponding one of said poles, a number of routines, and a processor cooperating with said sensor circuit and said number of routines to provide for each of said poles a corrected value of the current flowing through the conductor of a corresponding one of said poles as a function of a corresponding one of said values, the offset value for said sensor circuit for the corresponding one of said poles, the gain correction factor for said sensor circuit for the corresponding one of said poles, and the gain correction factor for the Rogowski coil of the corresponding one of said poles.