A Step Up

TPDDL transitions from AMR to AMI

Over the past few years, Tata Power Delhi Distribution Limited (TPDDL) has made significant improvement in its operational and consumer-related parameters. Notably, the utility’s aggregate technical and commercial (AT&C) losses have reduced to 7.92 per cent since its privatisation. The percentage of its defective bills has declined from 6 per cent to 0.2 per cent while the bill complaint resolution time has reduced to two days in 2019 from 45 days in 2002. Its impressive performance on these fronts has expanded its customer base from only 0.7 million in 2002 to over 1.7 million at present. TPDDL’s success on these parameters can be largely attributed to the implementation of advanced technologies to improve efficiency and consumer service delivery. It has deployed several technologies such as advanced distribution management system, which has replaced the conventional SCADA-DMS-OMS (supervisory control and data acquisition, demand management and outage management system) with features such as real-time integration of smart meter data and geographic information system (GIS), advanced metering infrastructure (AMI) and automated demand response.

The utility is now implementing AMI, a more real-time and automated system than advanced metering infrastructure (AMR). A look at TPDDL’s journey from AMR to AMI…

AMR architecture

TPDDL’s transition to AMR began in 2004, and it was the first utility that started experimenting with the technology. Under this, all 30,000 customers above 10 kW have moved to AMR. In addition, it has installed around 70,000 low tension current transformers (LT-CTs), and high tension (HT) and distribution transformer (DT) meters, which contribute to 70 per cent of its revenue. TPDDL has also deployed indigenously developed software AMRDA to ensure seamless reading and analysis. The key functions of AMR technology include download of billing data, theft analytics and data archival.

The deployment of AMR and analysis software by TPDDL led to a surge in the load booked. It increased from 9.1 MW in 2004-05 to 45.1 MW in 2005-06 and 67.3 MW in 2006-07. Meanwhile, the actual AT&C losses reduced from 33.79 per cent in 2004-05 to 26.32 per cent in 2005-06 and 23.73 per cent in 2006-07. In 2011-12, TPDDL updated its AMR analytics system, thus increasing the load booked to 31.16 per cent. The load booked remained stagnant until 2017-18 and then increased to 27.29 per cent in 2018-19. The overall success rate of deploying AMR technology has been 98 per cent per month.

Shift to smart metering and AMI

AMI or smart metering forms the core of smart grid architecture. It comprises smart meters, data concentrator units, a meter data management system and an HES. AMI enables two-way communication, and allows consumers to manage their electricity consumption with its hourly/ daily reading frequency. In contrast, AMR allows one-way communication with a monthly reading frequency. 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 the power factor and load.

TPDDL’s AMI project entails the installation of 300 routers and 66 collectors (for 0.5 million meters) under a radio frequency (RF) mesh canopy. For this, the ground-level survey has been done on more than 500 sites. Of the 110 ICT sites, 60 have been selected for collector installations. Further, of more than 7,000 substations with RMU sites, 300 sites have been selected for RF planning. Noise analysis has been done in 305 locations and network planning has been completed.

After implementing SCADA-DMS, enterprise resource planning and billing systems, the next key technology identified by TPDDL is smart metering, which has gained adoption under the Ujwal Discom Assurance Yojana. Smart metering has been crucial as it allows faster outage detection and restoration of service. It provides customers with greater control over their electricity use when coupled with time-based rates. It enables customers to make informed decisions by providing highly detailed information on usage patterns based on analytics. About 1,735 DT meters, 134 routers and seven collectors were installed as of October 31, 2018. The utility replaced 60,000 meters in 2018-19, and aims to replace another 150,000 meters in 2019-20.

The utility has a robust communication network. At present, the communication rate is 92 per cent against the target of 99.9 per cent. Further, the firmware has been updated in all collectors and routers, and is being updated in meters. Site surveys for additional collectors have been started. As per the SAP data updated in the head-end system (HES), of the 32,105 DT, 1P and 3P meters installed as of February 2019, only 6,043 did not report their billing data, which is a success rate of 81 per cent.

Challenges

TPDDL is migrating from HES version 7.3 to 7.4. Since the database structure changes with each update in the HES version, the data extracts from meters are not generated in the desired format for billing. This is one of the key challenges faced by the utility. Another challenge faced by TPDDL is delays in the delivery of adapters for field data downloading and site identification for router installation in the rural belt. The utility is also witnessing a delay in the issuance of IS 16444 certification for HT transformers and CTs. The certification for single-phase and polyphase transformers was received in September 2018. Type testing of smart meters is also delayed due to non-readiness of the labs. Further, the utility faces consumer resistance in isolated areas. Steps need to be taken to develop the meter data management system (MDMS). TPDDL has developed the revenue protection logic for MDMS internally as the feature is not available in MDMS. There is also a capacity limitation of pre-MDMS to 50,000. Lastly, there is also a gap in the development of the new version of HES and MDMS.

Future roadmap

Due to the rising energy costs and demand, and increasing renewable energy integration, the existing energy infrastructure has become obsolete. TPDDL’s transition from AMR to AMI has allowed real-time monitoring of energy consumption. Moving ahead, TPDDL aims to adopt a customer-centric approach, with a focus on creating awareness. AMI will provide customers the autonomy to decide their consumption patterns. It will also enable energy auditing on a wider scale. TPDDL is evaluating other technologies such as RF mesh at 865-867 MHz, 2.4 GHz and 5.8 GHz. The 865-867 MHz RF mesh is being explored as a hybrid technology with optical fibre, which enables fast data transfer.

Net, net, the implementation of advanced technology and intelligent energy management will help reduce energy use, spending and emissions, and provide a solid foundation to build a smarter energy infrastructure.

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