Smart meters in the electricity sector measure power consumption in real time, detect theft, reduce expenditure on manpower, and furnish detailed data on consumption to help consumers plan their usage efficiently. Their twin capacities of bidirectional communication and remote load connection and disconnection make them distinct from other meters. A smart meter essentially consists of a basic static meter, a network interface card facilitating communication, and an internal load switch.
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, PLC (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 of these meters.
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, 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. It is envisaged that in the long term, these services will be integrated to provide better service.
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.
In addition to the above, to support communication, there are two technologies available for backend AMI systems, one being optical fibre and the other being the cellular system, to receive the data sent by smart meters. The optical fibre technique is a costly proposition while cellular-based back-end technology is very affordable, but its reliability depends on the frequency used.
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. It would be justified to assert that it is in the electricity sector that smart meters will offer the highest utility and potential.
At CESC Limited, several pilot projects have been implemented. Around 23,000 smart meters have been installed, of which 19,500 are RF-Mesh-based smart meters and the remaining are based on cellular technology. This year, the company’s plan is to install 70,000 meters so as to improve remote billing capabilities and reduce human intervention in billing, integrate legacy IT applications, and modernise billing systems so as to control administrative expenses and increase revenue intake. The company also has a communication network in place. However, there are some issues and concerns since AMI is a nascent technology and its supply chain ecosystem is still developing. Owing to this, the price per unit of smart meters is effectively so high that it renders the replacement of the current AMR technology unviable.
Further, 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 technology 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.