NOVELTY - The system (10) has an electric power router (21) which transmits the information between specific addresses and accompanies electric power while providing the address for identifying each of the electric power apparatuses provided in and connected to the electric power grids (12a,12b). An internet connection (22) carries the information connected with the router and accompanies the power from router. An electric power line monitoring apparatus (25) is connected with internet connection to monitor the grid based on information accompanying power received from internet connection.    USE - System for monitoring electric power grid through wide network in electric power company such as distributed power supply of photovoltaic power generation (PV), wind power generation (WT), nuclear power, hydraulic power, and thermal power.    ADVANTAGE - The electric power line monitoring apparatus is connected with internet connection by the wireless unit to monitor the grid based on information accompanying power received from internet connection so that the internet is accessed regardless of the place and electric power grid monitoring is continued from the place distant at the time of emergency disaster. Thus, the prolonged stoppage of operation of power system resulting from the stoppage for monitoring apparatus during unexpected disaster is avoided effectively while reducing the investment cost with the reduces time for assembling the system. Since the electric power identifies the attribute of the electric power generated by the nuclear power, thermal power, or hydraulic power, the optimal operation and monitoring of system is performed effectively according to the attribute of electric power.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of the system for monitoring electric power grid. (Drawing includes non-English language text)    System for monitoring electric power grid (10)    Electric power grids (12a,12b)    Electric power router (21)    Internet connection (22)    Electric power line monitoring apparatus (25)