Smart meters are a key element of advanced metering infrastructure (AMI). An AMI system can detect electricity theft and component failure. It also permits remote disconnection and facilitates prepaid metering, which has proven to increase revenues substantially.
Smart meters are designed to provide constant communication to their respective distribution companies. Discoms prefer communication technologies for smart meters and AMI that are self-healing, and have limited operations and maintenance costs. The other feature that discoms prioritise while looking for communication technology is scalability, because non-scalable infrastructure is problematic when the whole business case for AMI installation is founded on economies of scale leading to low unit cost of production. Another vital condition that has to be satisfied is that meters need to be auto-reconfigurable, that is, able to commence operation on installation while also automatically reconnecting themselves to the grid after a grid failure so as to save time and manpower. A major prerequisite of smart meter communication technology is the robustness of the network, insulated from security interceptions and the exploitation of network vulnerabilities. Further, the communication technology should be such that it allows for the optimal deployment of network devices, thus controlling maintenance costs over the long term.
Communication technology choices
There are various types of smart meter communication technologies, characterised by variations in their operation, features and cost, which determine their suitability. These include cellular, RF-Mesh, Wi-Fi, power line communications (PLC)), LoRa and NB-IoT. Of these various versions, Wi-Fi communication technologies are quite vulnerable to data exploitation, according to several pilot studies. Wi-Fi-based smart meters communicate with the discom, but are prone to security issues and vulnerabilities in their current iteration. This dampens the confidence of discoms and raises concerns over the mass deployment.
Cellular technology provides data on a day-to-day basis. Cellular technology-based meters are useful for scattered deployment. However, network availability is not very good as it works on 2G. PLC involves embedding modules inside the electrical wires, and thus attracts the widespread interest of consumers as well as discoms. However, electrical lines are constructed keeping in mind only the purpose of electricity supply. Hence, the complex network, load variation and noise may cause interference, resulting in unstable communication. That said, they are useful in multi-storeyed condominiums despite the noise as they adjust the transmitter output power in accordance with the load impedance situations.
NB-IoT-based smart meters are very costly and are thus only suitable for deployment in urban clusters where the density helps in controlling costs. The RF-Mesh-based smart meters are most widely deployed in pilot projects in India because they are capable of seamless integration with other infrastructure services such as gas systems, water, cooling systems and heating systems. Moreover, they are reliable and scalable, and provide a constant flow of data.
RF-Mesh optimises the network devices with its inherent technology and is self-healing. The scattered deployment of RF-Mesh in an area with low density requires a huge canopy of network devices to render it workable. It must still be noted that RF-Mesh is ideal for deployment in high density areas since it fulfils the parameters of optimal network devices, self-healing, auto-configuring robustness, etc. Another reason to prefer RF-Mesh-based meters is that they can be recovered if they are stolen and can thus help prevent financial losses. Furthermore, with these meters, it is easy to detect and identify any anomaly or tampering in real time.
The way forward
Smart meters will have manifold applications in metering and their installation may provide enormous value to distribution companies by recovering the unrealised revenues lost due to theft, non-payment and erroneous computation. They will have widespread applications across infrastructure sectors like electricity, natural gas and water.
Choosing the best-suited end-to-end communication technology will be an issue that utilities need to address. Backward compatibility is also a concern with the selected communication technologies. Also, considering that it is a new technology, there is a lack of exposure and knowledge regarding its development. Moreover, this is a technology that requires a technically knowledgeable workforce with expertise in ICT in addition to a certain degree of knowledge about the working of meters. There is a need to hire staff that is experienced in operating this technology in order to manage the network seamlessly and ensure its data integrity. Lastly, there is a high initial capex required for RF-Mesh carpet deployment, which poses financial concerns, considering the weak financial condition of distribution utilities and their deteriorated balance sheets.