Apparatus for and method of attenuating power line carrier communication signals passing between substation distribution lines and transmission lines through substation transformers

摘要

A shunt three-phase wye-connected capacitor bank is connected intermediate a substation transformer and any source of zero-sequence power line carrier communication signals being transmitted on the substation distribution network to partially alleviate unbalance conditions in the communication signals which in the balanced condition are not passed by a three-phase substation transformer to the main transmission line. The signal is further attenuated by connecting the common wye-point of the capacitor bank through an inductance to neutral to form a shunt element of either an L or pi attenuation circuit with the series inductance of the substation transformer and the transmission line inductance forming the serial elements of the L or pi circuit. A further shunt element at another substation distribution network completes the attenuation circuit for the pi configuration.