Communication technology is a crucial component of advanced metering infrastructure (AMI). A robust communication technology, primarily for data transmission between head-end systems and smart meters, is vital for generating real-time alerts as well as for the transfer of a huge quantum of data that a smart meter generates. Although communication technologies such as fibre optics, powerline communication (PLC), and radio frequency (RF) mesh, no single technology meets all the requirements and, therefore, utilities often adopt a combination of these technologies across their distribution areas. While fibre optics offers the advantage of high bandwidth availability, PLC operates well on low voltage levels. Often, in order to make an informed decision, utilities conduct pilot projects with different technologies to delve deeper into technology deployment and the potential challenges.
AMI and its drivers
Discoms have been deploying technologies such as smart meters and AMI to enhance efficiency and improve monitoring. Smart meters enable two-way communication between the meter and the central monitoring system, thereby enabling remote monitoring. Further, with analytics, AMI can facilitate creation of a huge data pool that can be analysed and utilised to deliver better results. However, as smart grids gain momentum and technology advances further, network communication requirements also need to evolve. Utilities are now increasingly using AMI for varied applications such as load balancing, energy audit and improvement in billing efficiency. Since the implementation of AMI facilitates remote meter reading, it provides greater convenience at a reduced cost in comparison to a traditional meter. The remote monitoring feature is also useful for detecting meter tampering. Through real-time visibility, it provides alerts to a utility in case of unusually heavy load on the grid, meter bypassing and unaccounted-for consumption. Thus, by curtailing power theft, smart meters can substantially reduce the aggregate technical and commercial losses of discoms. Technology can also significantly improve utility load forecasting and the ability to procure the right volumes of power. Utilities can also implement time-of-use tariffs for different categories of customers and encourage load shifting with demand response programmes.
On the operational front, AMI allows remote reading of meter data, thereby eliminating chances of human error in the meter reading process. Besides, it also allows for the measurement of power quality data and asset optimisation. AMI data supports granular monitoring of power flow on the distribution network, helping utilities identify segments of over- and under-loading, which is important for system planning. Further, the identification of phase imbalances can significantly reduce the failure rate of distribution transformers (DTs). Therefore, AMI holds the potential to substantially improve operational and financial performance of distribution companies and deliver better customer satisfaction.
Smart grid communication options
Currently, there are multiple communication technology options to choose from, based on the requirements of utilities. There is no single technology that is effective for all kinds of networks. Each technology has its own advantages and disadvantages and, therefore, can be chosen for use on a case-to-case basis. For instance, fibre optic the communication has high bandwidth availability, but has issues related to laying and maintenance of the communication network. Though multiprotocol label switching technology is reliable, it is not cost effective as it requires expensive network equipment. PLC, on the other hand, is an effective solution for low voltage levels but it is largely untested in Indian conditions. There are also issues related to bypassing of transformers and transmission frequency in PLC communication. RF canopy is considered to be effective for quick deployment but faces reliability issues, which could hamper critical operations. Besides, it also faces issues of availability of frequency ranges. Cellular network (2G/3G/4G) proves to be effective only for a low volume of data transfer and faces issues of feasibility and reliability in certain areas. Narrowband internet of things (NB-IoT) is the latest effective solution for low volume data transfer. However, this is yet to be tested on various applications. Therefore, the best-suited technology solution for utilities is a combination of various technologies depending on the needs and requirements of different pockets in their distribution areas. In terms of RF mesh and cellular network, the operational expenditure of a cellular network is expected to reduce making it more competitive with RF mesh. Meanwhile, RF mesh topology is more reliable for dense areas as compared to a cellular network. Signal strength variation and technological obsolescence issues are areas of concern in a cellular network. Further, the RF mesh works on licence-free band, with lots of free users, walkie-talkies, etc. In terms of comparison of communication technology between a public and a private network, public carrier networks have proven to have a mixed record regarding survivability. There is a lack of adequate backup power on commercial networks, which results in the public network remaining unavailable until the utility electric service has been restored. Further, congestion severely affects availability of public networks in case of emergencies when availability is most needed. Public networks are also prone to hacking attempts. A private network, in contrast, offers high availability and security, but it suffers from a low life cycle. Globally, RF mesh communication technology is being widely used by utilities. Currently, it is being deployed by the Dubai Electricity and Water Authority, the Provincial Electricity Authority, Thailand, Singapore Power, Meralco, Tepco, the Pacific Gas and Electric Company, Oncor, Florida Power & Light, and United Energy Distribution. Besides this, with regard to NB-IoT, a pilot project is under way by the Lithuania State Utility to identify whether the technology will be sufficient for equipment control, and maintenance, replacement and updating of software. The roll-out of the technology is expected by the end of 2020.
BYPL’s AMI roll-out strategy
With regard to the roll-out of AMI by BSES Yamuna Power Limited (BYPL) by 2020, the discom plans to undertake a controlled roll-out (technology testing phase) where one cluster/subdivision is covered. The assessment will be conducted in terms of technology, benefits, vendors and inclusion of all use cases. The smart end point includes deployment of 35,000 meters. Meanwhile, during 2021-24, the discom plans to undertake area-wise mass roll-out of AMI involving real-time monitoring of DT load, automated meter reading, automated outage detection and analytics. Further, BYPL is planning a pilot project in the country, in parallel with Reliance Jio, to assess the performance of NB-IoT technology.
Challenges and the way forward
One of the biggest challenges for discoms is to keep pace with the constantly evolving technology. With new technological solutions emerging at a rapid pace, older technologies are fast becoming obsolete. Thus, utilities must adopt communication solutions that are scalable and can adapt to different circumstances. Another major challenge is handling the quantum of data transmitted from meters. Though this data can provide a lot of insights to utilities, managing the data can be a problem. To this end, utilities must support advanced communication technologies with sophisticated data management tools in order to efficiently manage and analyse the data. Apart from this, while adopting any communication technology, utilities need to put in place various checks and balances in order to ensure robust cybersecurity.
Based on a presentation by Lalit Kumar, Head, IT Infrastructure, BYPL, at a Power Line conference