Combined Instrument Transformers are special measuring transformers which combine the functions of a current and a voltage transformers. They are generally used where space is a constraint. Typical scenarios are when measuring transformers need to be added in a functioning substation.
![](http://4.bp.blogspot.com/-PVl86xA-eE0/TvCZVOvUbfI/AAAAAAAAFJA/O-k1C0lpuOw/s200/combined+instrument+transformers.jpg)