ABB has launched a new generation of magneto optical current transducer (MOCT-P) optical instrument transformers for relaying applications suitable for high-voltage networks.

The rated voltages range from 72 kV up to 800 kV. Current sensing is based on the well-known magneto optical Faraday effect. The free-standing sensor column communicates with the rack-mounted electronic module, located in the control house, by means of 200/230 multimode optical fibers. By this, the electronic module and relays are isolated from voltage surges.

The new product’s primary benefits are the fast multiple analog 200mV low voltage outputs capable of interfacing with several commercially available microprocessor relays, and the environmentally friendly oil and SF6 free design. Its low weight enables high flexibility in mounting arrangements and eases handling on site.

An additional key feature is the highly accurate reproduction of fault events due to lack of any magnetic distortion effects common in conventional current transformers with iron cores.The high bandwidth of 10 kHz adds opportunities in the area of power quality products. The MOCT-P optical instrument transformer was tested according to the latest and ANSI standards or electronic current transformers.The MOCT-P can be used in many applications such as in transmission line-, bus-, transformer-, breaker- or distribution schemes.

The optical instrument transformers MOCT-P are manufactured at ABB’s high-voltage facility in Youngwood, Pennsylvania, USA.