This post is an excerpt from an article appeared in ESI Africa magazine.
With the use of ubiquitous PLC, reduced deployment time and costs as well as increased maintenance planning are attainable. Currently, one of the main application domains of PLC is the smart grid where bidirectional connectivity is necessary to connect sensors and control units for monitoring and optimisation of power flows and better integration of renewable energy sources. One of the key components of the smart grid is smart metering.
The smart metering market worldwide is significantly high with forecasts predicting the deployment of 400 million meters by 2020 in China, 240 million in Europe and 150 million in North America.
In Europe, it appears that PLC will play a dominant role, already in Italy 30 million PLC meters have been installed, while other countries have several millions in the field and are accelerating rollouts such as Spain and France. PLC nodes have the potential to act as deep network probes in all domains, from transmission, to distribution to customer level. Therefore, PLC will offer infrastructure that is able to gather and exchange high volumes of data from meters and sensors to analysis and operation centers. In turn, this will enable more effective monitoring and proactive maintenance, higher safety, higher efficiency, better planning and execution as well as higher customer satisfaction. PLC technology has reached high maturity and worldwide standards have been completed.
Supporting the electrical grid network
Bidirectional connectivity offered by PLC can enable better grid management and maintenance. In the transmission side of the network, it offers support to a number of applications such as remote station surveillance, state estimation and overhead cables monitoring. PLC provides connectivity between sensors located in medium voltage substations so that status can be monitored, faults detected and isolated, and islanding events prevented. The capabilities of smart meters connected via PLC in the low voltage network can be extended to actively involve customers through the implementation of demand side management and demand response mechanisms. To this extent, home area networks using PLC can provide reliable and low latency data exchange between sensors and devices for real-time load control together with a wide set of IoT applications for increased security, comfort and quality of life. PLC also enables management and control of microgrids where distributed energy generation from renewables requires continuous supervision. In addition, PLC offers a link between electrical vehicles and the grid, thus enabling several applications from customer identification and pricing, to control the state of charge, to delivery of information and entertainment services inside the vehicle. Finally, the PLC network can be used to remotely manage assets in the field.
From communications to grid diagnostics
Despite the maturity achieved by PLC technology, still the question arises whether further advances can be made. This is why research is still very vivid. At the Lab of Embedded Communication Systems of the University of Klagenfurt, Austria, research, prototyping and tests are done on all aspects relevant to PLC. Measurement campaigns are carried out to characterise the communication medium and develop models that can be used in simulation tools; novel modulation, coding and signal processing algorithms are developed to increase performance and enable high flexibility to spectrum usage and the fulfillment of EMC-EMI regulations.
Indeed, standardisation bodies did not pose much focus on BB-PLC technology for true smart grid applications over outdoor networks since the main application of BB-PLC was home networking.
Furthermore, studies are carried out to devise adaptive media access protocols, routing mechanisms and assess the performance of a full PLC network. In addition, the deployment of hybrid networks is foreseen, where PLC is used in combination with wireless technologies. This approach enables the exploitation of the diversity offered by multiple communication media and therefore can grant higher coverage and better fulfillment of the application requirements. Another area where advanced research is carried out relates to the idea of embedding sensing capabilities to the PLC transceivers.
The goal is to embed more intelligence to PLC devices that can act not only as communication nodes but also as distributed sensors for network diagnostics. The analysis of PLC signals, and more in general of the electromagnetic field, can enable the identification of faults and cables degradation, to infer the status of the grid topology, to identify feeders and phases etc. These new solutions will provide higher benefits to utilities and distribution system operators.
It is also important for professionals to have knowledge and a firm grasp of PLC technology and the progress made. This can help to better engineer PLC systems and plan deployments by the electrical utilities. It should be emphasised that PLC is not just a communication technology, but rather it is a technology where network nodes communicate through the electrical grid and therefore it is important to understand and be acquainted with both domains.
A.M. Tonello, “Why You Should Consider the Uptake of PLC Tech,” ESI Africa – Utility Maintenance Focus, vol. 3, pp. 34-36, July 2017.
A.M. Tonello, Grid diagnostics enabled by PLC for sensing, NES 2017.