Decoupling networks for promoting power line carrier systems

Electricity authorities are constantly confronted by congestion in frequencies on their power line carrier (PLC) networks and they quite often look for alternative modes of communication which could be quite expensive. At a time when there is rapid growth in power systems, the need for exclusive communication circuits becomes significant. Therefore, the issues connected with power line carrier networks become more complex, particularly when the frequency approvals from the Government are not easily obtainable. Network decouplers have emerged as a dependable and economical solution. With the practices of selecting marginally-sized outdoor equipment and wide preference of onsite tuning, decouplers have been tried in some installations earlier. The gains sought thereby seem to be quite limited and often confined to teleprotection. The Indian experience with network decouplers, however, has proved to favour PLC systems not only for the teleprotection requirements but also for speech communication, monitoring measures and supervisory controls. Extensive short-circuit tests and modern dielectric technology have enabled manufacturers and utilities in realising these aims quite economically