India’s aggregate technical and commercial (AT&C) losses are among the highest in the world, averaging around 26 per cent as per official estimates (though the actual losses are estimated to be higher). This is primarily due to the lack of proper energy accounting by distribution utilities at all levels (feeders, transformers, consumers, etc.). For instance, Paschimanchal Vidyut Vitran Nigam Limited’s (PVVNL) metering coverage is just about 55 per cent. Of its 4.2 million total consumers, 2.3 million are metered consumers and 1.9 million are umetered.
New metering technologies can play an important role in improving the operational performance of distribution utilities. Though most of them have taken steps to replace the older electromechanical meters with electronic ones, the adoption of advanced metering technologies like prepaid metering and smart metering is still very scattered.
The older-generation electromechanical meters only record active energy consumption. Moreover, the wear and tear of their moving parts directly affects accuracy and results in revenue losses. Hence, nearly all distribution utilities are now replacing these meters with electronic meters.
Electronic meters can accurately record different kinds of power-related parameters, including instantaneous voltage, current, reactive energy, power factor, frequency, as well as the consumer’s active energy consumption. They can also be combined with remote reading and time-of-day (ToD) payment facilities.
The deployment of electronic meters has resulted in better revenue realisation for utilities. It has also helped reduce billing cycles by introducing spot billing. The manual readings in electromechanical meters caused relatively longer billing cycles and led to delays in billing and the collection of dues.
New metering technologies
Metering technologies are constantly evolving with the aim of eliminating manual meter reading. For instance, some utilities are adopting infrared port meters that make billing more accurate. Meanwhile, the implementation of automated meter reading (AMR) in agricultural feeders, distribution transformers (DTs), and low tension (LT) and high tension (HT) industrial services has considerably improved the metering efficiency of utilities.
At Southern Power Distribution Company of Andhra Pradesh Limited (APSPDCL), the man-ual billing of LT and HT consumers is being cross-checked with the billing parameters measured by meter reading instruments (MRIs). To further improve accuracy and bring in greater transparency, AMR is being implemented as well. As all feeder energy meters in the utility are electronic, their MRI data is analysed for any deviation in supply hours.
Bangalore Electricity Supply Company Limited (BESCOM), among the country’s few advanced distribution utilities in terms of technology deployment, has taken several new metering initiatives. These include the introduction of thread-through-type composite meter housing boxes for distribution transformer centres (DTCs), the three-element metering system as against the earlier two-element system, the replacement of 0.5 class current transformers (CTs) and potential transformers (PTs) with 0.2s class CTs and PTs, ToD metering, prepaid metering for LT installations using smart card technology, net metering, and the installation of meter data acquisition systems (MDAS).
PVVNL, meanwhile, is planning to implement smart metering in Billari and Gulawthi, covering a total of 13,000 consumers in these areas.
The following sections discuss the different metering technologies that have already been adopted or are being implemented by utilities in India…
Prepaid metering, or pay-as-you-go metering, allows consumers to pay in advance for the energy they are planning to consume. Prepaid metering offers utilities the benefit of 100 per cent cash collection and provides consumers enhanced services. It is not a new concept in the Indian power sector. In 1999, the Brihanmumbai Electric Supply and Transport Undertaking had implemented a prepaid metering pilot project in Mumbai. Prepaid metering projects are currently under way in Delhi, Ghaziabad, Jamshedpur and Karnataka as well.
The prepaid metering mechanism eliminates the billing cycle and leads to better revenue management. The need for manual disconnection or reconnection does not arise either, thereby leading to lower operational costs.
Prepaid metering also provides flexibility to consumers in terms of payment options and topping up additional units, just like prepaid cellphones. However, an operational constraint associated with this is that it is suitable for only whole current meters with inbuilt relays.
In a tariff order dated April 2012, the Karnataka Electricity Regulatory Commission (KERC) ordered the state’s discoms to cover all tem-porary installations under prepaid metering. In this regard, BESCOM has awarded a contract for the implementation of prepaid meters using smart cards at the Indiranagar Division for LT consumers to Supermax Components Private Limited. The Rs 49 million pilot project involves the installation of about 3,525 meters, 100 of which have been installed in the first phase.
BESCOM has initiated DTC metering in two phases. In the first phase, towns under the Restructured Accelerated Power Development and Reforms Programme (R-APDRP) will be covered and 42,500 DTC meters installed. Non-R-APDRP towns will be covered in the second phase, with 35,000 DTC meters being installed. BESCOM has adopted thread-through-type metering for DTCs in non-R-APDRP towns, which offers several advantages over conventional DTC meter cubicles.
The thread-through-type system for DTC metering is compact and light and entails a reduced installation time of four to six hours. The CT is integrated and busbars or external housing boxes are not required. The thread-through system helps eliminate errors due to wrong connections and broadens management capabilities by monitoring current, voltage, ambient temperature, overload, underload, high/low voltage, etc.
On the other hand, conventional DTC metering cubicles are heavy and bulky and require about 8-12 hours for installation. The connections inside the metering cubicle are prone to errors and a lot of care must be taken to avoid meter reading errors. In addition, the meter cubicle is prone to rusting as it is made of metal.
HT ToD metering
KERC had mandated the state’s discoms to implement ToD billing for consumers with a sanctioned load of 500 kVA and above. BESCOM completed this project in September 2012, having covered around 1,278 consumers. Under the project, existing meters were reprogrammed to three time zones for ToD billing: 2200 hours to 0600 hours (non-peak hours), during which the applicable tariff was less than the normal tariff; 0600 hours to 1800 hours, during which the normal tariff was applicable; and 1800 hours to 2200 hours (peak hours), during which the applicable tariff was higher than normal.
A net meter is a bidirectional energy meter that records energy exports by rooftop photovoltaic (RTPV) plants as well as imports (consumption of the energy supplied by discoms). Consumers can install their own solar RTPV plants and use the generated energy for their own usage and feed any excess power to the utility grid. The net consumption is billed at normal tariff slabs and the meter reading taken by the distribution licensee forms the basis of the commercial settlement.
BESCOM has already rolled out 67 RTPV installations with the net metering facility by installing bidirectional meters. It has also invited expressions of interest for the empanelment of vendors for the further supply of bidirectional meters.
Smart grids and AMI
Smart grids are essentially aimed at setting up better infrastructure for the delivery of electricity. They utilise information and communication technology so that power systems can operate more efficiently, reliably and safely. In this context, advanced metering infrastructure (AMI) is crucial. It comprises smart meters, data concentrator units, communication networks, MDAS, and meter data management systems (MDMS), which are all integrated on a single platform.
The Electricity Department (ED), Puducherry, is implementing a pilot smart grid project in association with Power Grid Corporation of India Limited. The functionalities under it include AMI, peak load management, demand-side management, demand response (DR), outage management systems (OMS), renewable energy integration with net metering, power quality management (PQM), microgrids, energy storage, electric vehicles with solar charging stations, and street light automation.
So far, a smart grid control centre (SGCC) has been established at Puducherry. Over 1,650 smart meters and 33 data concentrator units (DCUs) have been installed, covering nine DTs. The meters of different communication technologies (RF 2.4 GHz, RF 865 MHz, PLC, BPLC, GPRS) have been successfully integrated at the control centre and the interoperable system has been implemented with reliability and security.
For OMS, eight monitoring systems have been installed to monitor the health of DTs in terms of oil temperatures and oil levels. Around 21 fault passage indicators have also been installed to provide alerts to the SGCC and maintenance crews.
Under PQM, an automatic power factor controller and insulated-gate bipolar transistor-based filters were installed. To facilitate renewable energy integration, smart meters with net metering were installed for three rooftop solar consumers.
These measures have led to reduced AT&C losses and increased revenue in the Puducherry ED through improvements in billing and collection efficiency. The online energy accounting and auditing system has helped in the detection of tampering and theft, revenue protection and system load analysis. There is also a better understanding of the system load for designing DR programmes, and the utility has benefited through improved load management due to the optimal utilisation of assets and reduced blackouts. This has reduced the capex for capacity addition and expensive peak power purchases. The other benefits are improved power quality, reduced outage times, better crew and asset management, street light automation, and facilitation for prosumers to inject renewable energy back into the grid.
Apart from utility benefits, the implementation of the smart grid pilot project has a slew of advantages for consumers, providing them greater control over energy usage and billing. They can enjoy a reliable power supply, longer appliance and gadget life due to improved power quality, and the ability to inject excess power into the grid. They also do not need to depend on backup power solutions. The pilot project has led to an overall improvement in the consumer satisfaction index.
Issues and challenges
Most Indian discoms lack the initiative required for implementing smart grid technology. The lack of skilled manpower and high smart meter costs are the main issues as the initial investment in purchasing these meters is quite high. There is also a lack of clarity when it comes to the application of smart grid technology in the Indian context.
At present, the network infrastructure of distribution utilities is not sufficient for the deployment of smart metering technology. The existing electronic meters allow only one-way communication and are therefore not suitable for smart metering applications. Utilities have already made significant investments in upgrading existing mechanical meters and older static meters; therefore, making re-investments in smart metering will be an add-itional burden, especially since most utilities are dealing with high financial losses.
There are also issues related to capacity building, data availability, last mile connectivity, and radio frequency. The operational challenges include latency in signal reception, the incomplete coverage of the communications network, and concerns related to end-to-end interoperability standards for integrating AMI systems. In addition, the lack of consensus on the specifications of low-cost single-phase smart meters by all stakeholders, the industry’s lack of readiness for the manufacture of smart meters, manpower limitation, and the lack of clarity about the functional requirements of smart meters are other pressing issues.
The way forward
The major concerns of distribution utilities in India include the combination of an ever-growing energy demand and a non-commensurate supply, which leads to load shedding. The ageing infrastructure in the distribution network is another problem, as is the lack of sufficient technology deployment, which leads to delays in restoring breakdown outages. The lack of skilled manpower and high levels of dissatisfaction among consumers are other issues.
These days, consumers are better informed and demand improved services from discoms, including uninterrupted electricity supply and quicker grievance redressal. Consumers expect utilities to provide facilities for the faster removal of faults in electricity distribution, accurate billing systems and convenient payment options.
New metering technologies are now being designed to meet consumer expectations, in addition to streamlining the operational performance of utilities. Going forward, distribution utilities are expected to adopt new metering technologies and switch to smart grids after garnering key lessons from the various pilot projects under implementation.
Based on presentations by A.K. Gupta, Chief Engineer, PVVNL; D.V. Chalapathy, Divisional Engineer, APSPDCL; and S.A. Satish Kumar, General Manager, BESCOM at a recent Power Line conference