H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
H02J13/00—Circuit arrangements for providing remote monitoring or remote control of equipment in a power distribution network
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04Q—SELECTING
H04Q9/00—Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom
H04Q9/08—Calling by using continuous AC
H04Q9/10—Calling by using continuous AC using single different frequencies