Interfacing optical current sensors in a substation

Optical current sensors are achieving increased acceptance and use in high voltage substations due to their superior accuracy, bandwidth, dynamic range and inherent isolation. Once deemed specialized devices intended for novel applications, optical sensors have risen to a performance level exceeding conventional magnetic devices. Optical current sensors have pushed the limits of measurement beyond what is presently available with conventional technology. In order for users of optical transducers to realize the complete benefits available from this new technology, an understanding of the differences between conventional transformers and optical sensors is critical. Key users who must understand these differences include planners, apparatus engineers, substation designers, maintenance personnel and system operators. Interfacing optical sensors to existing meters and relays is one of these key differences and is the primary focus of this paper. Providing a simple method of interconnecting old and new technology is a necessary and required step in the path to acceptance of optical sensors, and if given this, it will ease the transition to advanced systems within a substation.