Accurate metering and billing, and better load management are the top priorities for power distribution utilities. Therefore, they have implemented advanced metering infrastructure (AMI) and adopted automatic meter reading (AMR). AMI allows two-way communication with the installation of smart meters. This not only helps the utility in better network planning and load management, but also provides consumers greater control over their electricity consumption and energy bills. Meanwhile, AMR, through which meter reading is remotely recorded without any human interference, has gained wide acceptability among utilities given its benefits of accurate billing, and faster detection of meter tampering and theft, and better network management.
AMR
In AMR systems, usually GPRS-based intelligent modems are installed at availability-based tariff (ABT) meters to capture meter data and communicate it to the central data centre. Typical interaction touchpoints of an AMR application include databases of billing information; consumer, meter and SIM details; and distribution transformer (DT) consumption and loss information. With no manual intervention, AMR helps reduce commercial losses, detect meter tampering and thefts, reduce provisional billing and billing cycle days as well as the number of consumer complaints.
In the power distribution segment, Tata Power Delhi Distribution Limited (TPDDL) became the first utility to implement AMR for all connections above the 0.4 kV level. It has installed around 70,000 low tension current transformer, high tension and DT meters, which contribute to 70 per cent of its revenue. Further, indigenously developed software AMRDA carries out seamless reading and analysis.
In the transmission segment, one example AMR implementation is by Gujarat Energy Transmission Corporation (GETCO). As of May 2018, GETCO had installed 1,420 interface ABT meters at concentrated (conventional generation stations) and scattered (non-conventional stations and substations) locations. The transco has developed an energy accounting and scheduling software, which has been customised with AMR functionalities.
AMI
Broadly, AMI comprises smart meters, a meter data acquisition system (MDAS), a meter data management system (MDMS), and an integrated ICT infrastructure. Further, an enterprise service bus and business analytics are used to consolidate the operations of AMI. Apart from the essential features of an ordinary meter such as meter reading and billing, and tamper detection and energy auditing in case of a smart meter, the data generated in the meter is utilised at the outage management system and distribution automation segments for demand forecast, volt-var control, network planning, asset management and load management purposes.
AMI entails two-way communication, and allows consumers to manage their electricity consumption. It provides consumers greater control over their electricity use. It also provides real-time alerts to consumers in case of violation of threshold values in power factor and load.
One of the examples of AMI implementation is TPDDL. The discom’s AMI project entails the installation of 300 routers and 60 collectors (for 0.5 million meters) under a radio frequency (RF) mesh canopy. As of May 2018, the discom was halfway through the installation of its metering infrastructure.
Communication technology
A robust communication technology forms a crucial part of the successful operation of AMI. The choice of communication technology depends on varied factors such as geographical terrain and the available network.
One of the widely and successfully deployed communication technologies for AMI in the country is RF mesh. It is used for in-house communication purposes and for communication between meters and data concentrators. RF mesh has high market penetration and a short gestation period. Besides, the technology has witnessed a decline in prices in recent times. On the downside, RF mesh technology fails to deliver the desired results in basements and very thinly laid-out areas.
GPRS is another technology used for communication in AMI. It is widely used for communication between meters and data concentrators in rural areas as well as for back-end communication purposes. With regard to another communication technology, namely, power line communication (PLC), pilot projects in India have depicted that its performance varies with network conditions and installation practices of utilities. Some of the other communication technologies are Wi Max (high bandwidth); IP-based communication (highly secured communication) and long range (delivers excellent results but low penetration in the Indian market).
With regard to network service pro- viders, certain technical specifications are desired for the successful implementation of AMI and AMR. These include dual band (900/1800 MHz GPRS) for connectivity of SIMs, private access point name for data security, static internet protocol for each SIM, data plan of 20 MB per month per SIM, and a pulse rate (packet size) of 5 kbps or lower.
MDAS
The MDAS remotely acquires interface meter data through AMR from the selected consumer meters. MDAS undertakes real-time and historical data acquisition, and performs supervisory functions such as processing, monitoring, analysis and diagnostics. With no human intervention, MDAS acquires data pertaining to operational parameters; helps in accurate billing; generates MIS reports for proper planning, monitoring and decision support; and performs corrective actions after receiving directions from the management.
Issues and challenges
For the successful implementation of AMR and AMI solutions, the preparation of a suitable installation site is crucial. Site readiness for modem installations, Phase 1 or Phase 3 power supply, and good signal strength to send meter data files securely or in an encrypted format are essential. Further, at the field level, a number of hardware devices need to be installed such as a GSM/ GPRS modem, a communication cable between an ABT meter optical port to a modem port, and a SIM provided by the network service provider. On the other hand, at the control centre, an MDAS server and an MDM server need to be installed. Another challenge in AMR/ AMI pertains to non-communication encountered owing to optical/serial cable not properly connected, weak signal or no signal, antenna damage/missing, and SIM card not working, among other things.
Another area of concern in AMR and AMI implementation is cybersecurity. For network security purposes, RF mesh technology is encrypted and IPv6 compliant. It also offers certificate-based and hardware security. Meanwhile, in the case of GPRS, there are issues of fake identities, tampering with communication, and cellular jamming. Besides, GPRS in India is not IPv6 compliant.
To conclude, while a host of technology solutions are available for the implementation of AMR/AMI, for the best outcome, utilities need to identify the most appropriate technologies in view of their requirements. Besides this, change management is crucial for the smooth implementation of AMR/AMI.
