Patent ID: 7511468

Claim:
A portable apparatus for measuring harmonic voltages and currents on an alternating current electric power distribution grid, said alternating current having a fundamental frequency, said apparatus comprising: a. a plurality of current measurement channels, each such current measurement channel equipped with an associated current transducer; and b. a plurality of voltage measurement channels; and c. a current calibration source, said current calibration source having an output, and said current calibration source configured to provide a means of calibrating the current measurement channels and their associated current transducers for gain and phase, at frequencies higher than the fundamental frequency; and d. a voltage calibration source, said voltage source having an output, and said voltage calibration source configured to provide a means of calibrating the voltage measurement channels for gain and phase, at frequencies higher than the fundamental frequency; and e. said current calibration source and said voltage calibration source configured so that the current calibration source output and the voltage calibration source output are physically separated, and f. said current calibration source and said voltage calibration source constructed as a physically embedded element of the portable apparatus.