The LJ-2/4/7 zero sequence current transformers are used in indoor environment, and provided for electric power systems of rated frequency of 50/ 60 Hz and rated voltage of 35kV and below. The relay DD-11/60 matches with this model. All the versions meet standards IEC60044-1 and GB1208-2006. The pro ducts are used in metering electric energy, voltage controlling and relay protection applications.