Optical Solutions for AC
The Alstom optical current sensor brings a new level of accuracy to sensing over the range between 1 Arms and 63 kA rms. A lightweight dry type insulator and window head design allow pedestal mounting or suspension from rigid bus. The reduced size and weight are attractive benefits over conventional oil-filled equipment, allowing placement in compact substations or in retrofit applications where space may be limited. Its broad dynamic range makes this current transformer particularly suited for independent merchant plants where extreme accuracy at both full power output and station service draw is demanded.
The COSI-MU integrates a set of analog voltages together with the full COSI product range, which includes COSI-CT, COSI-CM and COSI-CT F3.
The Alstom COSI-CM system takes advantage of a conventional voltage transformer coupled with the wide dynamic range of the optical current transformer. The optical current transformer has the same specifications as the COSI-CT. Coupling capacitor voltage transformers (CCVTs) are used in high-voltage and extra high-voltage transmission systems to provide potential outputs to metering instruments and to protective relays.
The Alstom flexible optical current sensor has a flexible fibre optic sensing loop that is easy to wrap around high-voltage bushings, generator buses, or other conductors in ways not possible with conventional current transformers. The sensing loop is an all-dielectric cable, which connects to standard Alstom Grid electronics giving the user the same high performance capability and output options as the high voltage current transformer. It is the ideal solution for installation in difficult spaces on a temporary or permanent basis.