Analog Design for a Power Transmission Line Sensing and Analysis VLSI Chip

Considerable interest currently exists in the use of application-specific VLSI chips for the sensing and control of power systems with a view toward achieving smart grids. This paper describes such a chip, one that performs sensing, analog preprocessing and digital analysis, with emphasis here on the analog circuits. There are three major subsections in the chip: the magnetic field coils, the analog preprocessing section - that includes A-to-D conversion, and the digital processing section. Two coils are provided on chip, one of which serves to sense the ac magnetic field, and the other can serve either as a driver coil or as a redundant sensing coil. The magnetic field itself can be generated by the power transmission lines, or for test purposes by the second coil. The paper discusses the analog VLSI design and fault tolerance issues, including the effect of placement of the frontend at two very different locations, one inside the sensing coils and the other outside of them. This allows for the evaluation of the interference generated though inductive coupling.