POWER LINE COMMUNICATION SYSTEM

PROBLEM TO BE SOLVED: To provide a power line communication system capable of reducing leakage of electric field from a distribution line by attenuating a different potential component from ground. SOLUTION: Electric power is tapped from two lines of a high voltage distribution line 3 and is connected to the primary side of a pole transformer 2, and the middle point on the secondary side is grounded by a ground line 10. Two lines on the secondary side are inputted in a combiner 7, and connected to a coupling transformer 7a through capacitor 7b constituting the combiner 7. The capacitor 7b is set to such capacitance that indicates a high impedance for a commercial frequency (50/60Hz) while showing low impedance for a high frequency. Since only the signal of high frequency is passed to the coupling transformer 7a while a commercial frequency is blocked, the capacitance of a transformer can be reduced. So, the signal of high frequency occurs on the secondary side of the coupling transformer 7a, which is inputted in a modem 6 through a twisted pair cable 8. COPYRIGHT: (C)2005,JPO&NCIPI