Amongst the several options that have emerged to cater to the dynamic needs of distribution utilities, a promising and multifaceted solution is a smart meter. Smart meters have played an important role in revolutionising system communication and making it bidirectional from the conventional unidirectional flow. Efforts are being mobilised both at the global and domestic levels in order to facilitate the large-scale deployment of smart meters and thereby enhance the operational efficiency of discoms. While smart meters are an effective solution for mitigating most issues that impact utility efficiency, it is imperative to select the right technology for communication as technology effectiveness depends on a host of factors.
Need for meter communication
Meter communication lies at the heart of system efficiency since it offers a range of benefits to the utility. To begin with, communication ensures remote monitoring of the utility’s infrastructure. It not only enhances the pace of work but also ensures the constant supervision of important systems.
Second, having a bidirectional communication system gives the utility access to a large real-time data pool, which can be analysed to rectify errors and plug technical gaps.
Next, deploying communication technology facilitates the creation of a transparent system which, in turn, establishes better consumer connect. This also ensures the proactive involvement of customers in the entire process. Further, communication technology aids in the timely detection of faults and, if supplemented by additional solutions, has the potential to identify the exact source of leakage/fault.
Lastly, communication is the need of the hour, even from a regulatory perspective. The revised National Tariff Policy, 2016 mandates the installation of smart meters for consumers. As per the policy, the deadline for the installation of smart meters for consumers with a consumption of over 200 units is December 2019. Since the countrywide installation is already running behind schedule, an increasing number of utilities are now adopting smart metering solutions.
Communication technologies
There is an array of technologies to choose from; however, it is essential to factor in all the important parameters while making a choice. To begin with, it is important for the utilities to decide whether the meter roll-out under consideration is scattered or clustered, since the requirements of these two segments are likely to differ. The next step is to gauge the risk-taking capacity of the utility. While a few utilities have a higher risk-taking capacity and are willing to try out solutions that have not been tested yet, others are relatively conservative and prefer deploying lab-tested technologies. After this, the next step is to prioritise entities along the value chain. It is imperative to decide whether the communication vendor would receive priority or the meter vendor. Alternatively, the utility may adopt a holistic approach that values all the participating entities equally. Lastly, in order to make an informed decision, utilities often conduct pilot projects to delve deeper into technology deployment and the potential challenges that may arise in the future.
Utilities can select the communication technology suited to their requirements from a number of options including power line communication (PLC), general packet radio service (GPRS) and radio frequency (RF) mesh communication.
PLC is a traditional and reliable technology available to electric power utilities for critical communication channel and protection signalling. In PLC, the RF signals are transmitted through power transmission lines. PLC has an appreciably higher mechanical strength as compared to ordinary lines, which implies that it remains unaffected even in adverse conditions.
GPRS is a cellular communication technology and was one of the first technologies that enabled a cell network to connect to the internet protocol network. GPRS uses the existing telecom infrastructure to transmit data from smart meters. GPRS solutions are well suited for areas where the use of PLC or RF mesh is technically inconvenient or too expensive. These solutions are not only cost effective but also have other advantages such as resistance to external interference and low average power consumption.
The RF mesh communication technology comprises radio nodes organised in a mesh topology. Wireless mesh networks consist of mesh clients, mesh routers and gateways. Mesh clients refer to laptops, cellphones and other wireless devices, and the mesh routers forward traffic to and from the gateways. A mesh network offers an advantage in terms of enhanced reliability. Even if one of the nodes of the network fails to work, the other nodes can be used for communication purposes. Further, the technology allows automatic clustering and de-clustering of meters when network devices fail or stop functioning. The biggest advantage of the technology is that it offers scalability and adaptability, and can thus be utilised for longer time horizons. In addition, it has self-healing properties that can significantly scale down operating costs.
CESC’s experience
CESC Limited has emerged as a pioneering utility in the smart metering domain. The discom recently crossed the 50,000 mark of smart meter installation in Kota, where it operates as a distribution franchisee. The utility has conducted a range of pilot exercises in the past for evaluating technology feasibility based on network conditions and other important parameters.
In February 2015, for instance, the utility completed a pilot project wherein it installed 25 meters based on RF mesh technology. The objective of the exercise was to evaluate the performance of the technology with respect to the scattered deployment of meters and for this purpose, one collector and two routers were deployed. The project was successful, indicating that RF mesh technology is a feasible option in the case of scattered meter deployment.
On similar lines, in June 2015, CESC used the same technology for randomly installed meters. The utility randomly deployed 25 meters across the pilot area. The communication devices used were a router, a bridge, a master bridge and relays. The pilot was conducted to evaluate the performance of canopy with respect to need-based scattered deployment of meters and data analytics (DA) applications. This project, too, was successful, and highlighted how effectively RF mesh can complement DA applications.
Further, in order to test the efficacy of RF mesh with ring main unit automation, CESC carried out another pilot in October 2015. An extender bridge and a connector were installed for the purpose. The outcomes of this pilot, too, were promising.
Earlier, In January 2015, the utility deployed PLC technology, which was tested with both the underground and overhead distribution networks. Three data concentrator units (DCUs) were installed along with the meters to test the efficacy of both types of networks. While the DCUs effectively communicated with the meters in the case of overhead networks, stable communication could not be established in the case of underground networks, as a result of which the DCUs had to be shifted. Thus, the results of the exercise indicated that PLC works better with overhead networks compared to underground networks. However, not all of the pilots of the utility have been successful. In November 2015, CESC conducted a pilot to gauge the viability of GPRS communication technology in the case of clustered deployment of smart meters in high-rise buildings. Nine meters were installed for the exercise along with a DCU. However, the meters failed to communicate real-time outage alerts to the utility.
CESC’s experiments reveal an important underlying fact that it is not just about installing the smart meter, but also choosing the appropriate communication technology.
Challenges and the way forward
The wide range of options in communication technology poses an equally significant share of challenges for the utilities. The foremost challenge for discoms is to keep pace with the constantly evolving technology. New technological solutions are emerging at an unprecedented rate, rendering various options obsolete. Thus, utilities must adopt communication solutions that offer scalability and can adapt to different circumstances.
Another major challenge is handling the quantum of data transmitted from the meters. Although this data can provide a lot of insights to the utilities, managing the data can pose a concern. To this end, utilities must supplement advanced communication technologies with sophisticated data management tools in order to efficiently manage and analyse the data. Further, customer ignorance is an impediment. It is important for customers to have a basic understanding of the technology to ensure better results. Awareness at the consumer end enables smooth flow of information, and prevents resistance to new technologies and solutions. This, in turn, allows utilities to better manage the distribution network.
Smart meter deployment in the country is gaining ground with each successive year. Although India is yet to make a complete shift to smart meters, the initial smart meter wave has already had a considerable impact on technology maturity and market offering. There is not only an emergence of new technologies, but also constant upgradation of the existing technologies in a bid to facilitate the shift towards digitalisation.
With inputs from a presentation by Susmita Sen, Manager, Metering, CESC, at a recent Power Line conference