A high dynamic magnetooptic current transformer with optimized signal processing

In the power industry current has to be measured for metering and protection purposes. Conventional sensor setups need two transformers to realize the high dynamic range. By a new mixed analog/digital signal processing algorithm, the performances of a high accuracy revenue metering and a fast, high dynamic protection metering magnetooptic current sensor were combined into one single unit. The system design is based on a rigorous investigation and optimization of the error sources in the signal processing chain. The results are proved by a demonstrator achieving a dynamic ranged from 0.05 to 100 times the rated current and a ratio root mean square error of less than 0.5 percent.