Adapting HomePlug C&C PLC for use in a low voltage smart grid

The paper presents the adaptations that were required to HomePlug Command and Control (C&C) V1.0 to meet the requirements, and deal with the issues, that arose out of a field trial of a low voltage smart grid deployed in a blanket fashion in Johannesburg, South Africa for Eskom by Util Labs and EON consulting. The field trial spanned 3 years and 27 000 supply points. HomePlug C&C based PLC was used as the primary communications mechanism inside the LV distribution islands. During the trial the LV distribution networks where mapped and instrumented extensively. The paper looks at a number of physical network parameters that influenced the deployment architecture and the development of the network protocol. The HomePlug implementation was modified to allow for transmission based on node and packet priority. This removed packet collisions. Fairness and bandwidth guarantees were implemented using a super frame co-ordinated by a network master. This allowed the PLC implementation to reach 95% channel utilization under very heavy loads of 30 simultaneously transmitting nodes. During the trial it was discovered that there was significant PLC leakage between LV distribution islands. PLC leakage introduces multiple masters and hidden nodes into the network. The protocol implementation was adapted to mitigate the impact of this.