A distributed optical current transducer (DOCT) and a current measurement method are proposed to solve the problem that the straight-through optical current transducer is vulnerable to crosstalk magnetic field interference. We established a mathematical model of the magnetic interference degree of DOCT. Analyzing and summarizing the characteristics of the magnetic interference degree distribution of DOCT revealed that there are six magnetic interference zeros outside of DOCT. Then based on the background of three-phase common box current measurement in a gas-insulated substation, a current measurement method of anticrosstalk magnetic field interference is proposed, that is, adjusting the direction of DOCT to make the interference current at zero magnetic interference point, to achieve the effect of anticrosstalk magnetic field interference. The experiment shows that the measurement error of DOCT is <0.15%, and the interference of the crosstalk magnetic field can be ignored.

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