The Mumbai distribution business of Reliance Infrastructure Limited (RInfra-D) is among the frontrunners when it comes to IT adoption in the Indian power distribution segment. Over the past decade, the distribution licensee has made steady investments in the deployment of IT with the aim of enhancing the effectiveness, efficiency and reliability of operations, and improving consumer satisfaction. RInfra-D is now exploring various technology options to improve automation and performance for making the distribution network smart grid ready.
RInfra has been the power distribution licensee in the suburbs of Mumbai for nearly eight decades. The company serves approximately 5.94 million consumers with a maximum demand load of 1,697 MVA across an area of 400 square km. Its network includes 4,137 km high tension (HT) cable length; 5,892 km low tension (LT) cable length; 3,042 MVA power transformer capacity; and 4,613 MVA distribution transformer capacity.
Over the past decade, RInfra-D has deployed IT systems covering the entire range of commercial and technical processes. For faster fault identification and restoration, the discom commissioned the supervisory control and data acquisition (SCADA) system in 2000, which was further integrated in 2005. A distribution management system (DMS) and fault passage indicators were also deployed in a phased manner to reduce fault isolation and supply restoration time.
Other key elements of RInfra-D’s automation initiatives include the deployment of automated meter reading (AMR), equipment management system (EMS), geographic information system (GIS) and outage management system (OMS). In addition, billing and customer care solutions have also been deployed to optimise the revenue cycle as well as meet customer needs for bill accuracy, ease of payment, effective complaint management, etc. Besides facilitating asset maintenance processes, the deployment of such systems has helped improve the reliability and quality of power. At present, RInfra-D ranks among the best performing discoms in India with a distribution loss level of 9.45 per cent and a reliability index of 99.97 per cent. Improving the reliability of power supply is especially relevant for RInfra-D as consumers in Mumbai have the option of switching operators. According to the company, it gained 19,300 new consumers during the first quarter of 2014-15 and regained all HT consumers who had migrated to Tata Power Company Limited in the past four years.
RInfra-D’s current initiatives in the field of IT deployment are focused on automation with the view of developing a smarter grid. The company is currently implementing a pilot project for remote integrated control and the automated monitoring of substations with various functionalities, including ring main unit control, distribution transformer monitoring, LT panel load monitoring, energy meter parameter supervision, door switching and motion sensing, and smoke detection. Under this system, the data flows from substation equipment to the feeder remote terminal unit (FRTU). From here, the data is either sent to the operator’s terminals at the SCADA control centre, or to the display terminal configured at each depot unit, or to the concerned engineer through SMS.
Another key initiative by RInfra-D is the deployment of intelligent electronic devices (IEDs) at 33/11 kV receiving stations in line with the IEC 61850 protocol. The rapid spanning tree protocol (RSTP) was selected for the project against the parallel redundancy protocol (PRP) as it gives N-2 redundancy compared to N-1. Switches and IEDs are also comparatively less costly in the RSTP. The deployment of IEDs has led to multiple benefits like the interoperability of smart IEDs, eliminating the need for large volumes of external cabling and saving space.
In the area of metering, RInfra-D has progressed past the deployment of AMR and started installing smart meters capable of prepayment, loss detection, remote connections and cry-out alarms. The company has already deployed 5,467 new radio frequency (RF) smart meters; more than 3,000 power line carrier smart meters; 2,616 RF retrofit communication boards; and a head-end system with mobile device management. Recently, the company also installed two tamper-proof theft averter or prevention boxes on a pilot basis.
RInfra-D is also in the process of upgrading its SCADA system. This entails replacing the server hardware and software with the latest versions; building operating system (OS) flexibility with the use of Linux OS; integrating SCADA with GIS; improving the graphical user interface; building DMS front-end protocol redundancy; enhancing SCADA and DMS functionalities; deploying light-emitting diode (LED)-lit rear-projection technology for video projection systems; upgrading the SCADA human-machine interface with the latest software and hardware configurations; and enhancing IT security.
Leveraging its experience in integrating IT systems in the distribution network, RInfra-D is also providing consultancy services to various state utilities under the Restructured Accelerated Power Development and Reforms Programme (R-APDRP). RInfra-D has been appointed the SCADA DMS consultant due to its SCADA deployment in eight cities in Maharashtra, two cities in Chhattisgarh, one in Bihar and one in Chandigarh. It has been appointed IT consultant by Karnataka and IT implementation agency by Chhattisgarh.
Enhancing primary equipment
RInfra-D is also exploring opportunities for increasing the smartness of its primary equipment. The company has deployed cast resin (dry type) transformers with aluminium low voltage (LV) foil windings, which have improved performance safety as well as reduced cost and weight. The option of replacing mineral oil with synthetic ester in existing transformers is also being explored as it helps increase safety and overload capacity. So far, retrofilling with synthetic ester has been done in two transformers. The company is introducing Jean Muller or Cooper Bussman fuse strips in distribution pillars and piranha connectors in mini pillars in order to make them touch-proof and theft-proof.
The use of tree-retardant cross-linked polyethylene cables with water blocking tapes is being considered to increase network reliability. The company is also considering the replacement of cone beam computed tomography-based flat-panel imager (FPI) with three-phase computed tomography-based FPI to enhance the reliability of DMS. In addition, discoms plan to remove crimping-type ferrules from 33 kV jointing and introduce cold shrink joints for easy and fast installation and enhanced joint life.
One of RInfra-D’s key future initiatives entails the deployment of smart self-healing transformers, capable of voltage injection on the LV side after sensing on the high voltage (HV) side, either in-phase or out of phase. The company is also exploring the deployment of residual current compensation ground fault neutralisers that can help ensure uninterrupted power supply during fault conditions. RInfra-D is also evaluating the option of integrating power cables with fibres which will eliminate the need for separate fibre optic cables. Fibres can also be used for SCADA connectivity, distributed temperature sensing, real-time thermal rating calculations, etc.
RInfra-D is in the process of deploying self-healing grids (SHGs) on a pilot basis for decentralised local fault location, isolation and supply restoration based on fault passage indicators and voltage presence indicating system sensors. Under this, switching is done automatically to isolate faulty sections and restore healthy circuits. With the deployment of SHGs, the fault isolation time has reduced to 20 seconds from 60 to 120 minutes before distribution automation and 5 to 10 minutes after automation. Similarly, SHGs have helped reduce losses due to last section faults to 0.0625 MWh from 30 MWh before automation and 5 MWh with automation. The loss because of first section faults has also come down to 0.0625 MWh from 15 MWh before automation and 2.5 MWh with automation.
Challenges and the way forward
Even as most distribution companies in India continue to struggle with the deployment of basic IT infrastructure, RInfra-D has comprehensively put in place all the major IT and automation technologies available for the segment. The company’s network stands smart grid ready, though there is a need to upgrade the decades-old complex mesh network, which presents a significant challenge in the deployment of next-generation IT and automation pilot projects. Other hindrances are related to incompatible primary equipment and the integration of stand-alone legacy equipment with diverse protocols.
Funding also emerges as a key challenge as R-APDRP funds are not available to private players. Not only does the deployment of IT infrastructure entail high capital expenditure but it also requires high operational expenditure since hardware equipment depreciates quickly and the software also requires frequent upgrades. Given these circumstances, projects become somewhat unviable at a rate of return lower than 35 per cent, which is often not available in India in the absence of a clear regulatory stance on the recovery of the cost of projects. Despite such challenges, RInfra-D stands committed to investing in technologies in order to enhance the reliability of power supply and improve customer experience.
Based on a presentation by Indranil Chatterjee, Assistant Vice-President, Central Engineering Service, Reliance Infrastructure Limited, Mumbai