Information and communication technology (ICT) has played a key role in attaining efficiencies and improving the operations of Tata Power Delhi Distribution Limited (TPDDL). The company considered various factors while designing its communications network. These include budget constraints and time frames; applications and services required to run the network; bandwidth estimate of each application and service per user; number of users and locations to be connected on the network; and centralised and decentralised server architectures as well as main and backup centres.

TPDDL’s ICT infrastructure

At the time when TPDDL took over Delhi’s distribution system from the erstwhile Delhi Vidyut Board in 2002, all grid substations were manned and control panels were not connected to a communications network. Under the first phase of creating an IT infrastructure for its network, TPDDL built a website and linked several office locations through 60 kbps point-to-point communication links.

A 10-year technology road map was then prepared for several technology improvements. Based on this, TPDDL implemented the grid substation automation system. Today, TPDDL’s 66/33 kV and 11 kV networks are completely automated and unmanned, with remote monitoring being undertaken from a central location. Several other important initiatives were also taken under the technology road map. These included the implementation of the geographic information system (GIS), distribution management system, outage management system (OMS) and distribution automation system.

The various IT applications in place are SAP-ISU and enterprise resource planning modules such as financials and controlling, plant maintenance, materials management, project system, and human capital management. Payment gateways have also been set up by the company. Further, two data centres – primary and secondary – have been established.

Over the next few years, as part of the next phase of the technology road map, the proposed initiatives to be implemented by TPDDL include the introduction of systems for enterprise application integration, field force automation and automated demand response.

The basic framework for implementing these technological improvements is a reliable and robust communications infrastructure. At TPDDL, the current communications infrastructure landscape  includes web and communication links for connecting all zonal offices as well as single-window customer call centres to register new connections and power supply complaints. The call centres are integrated with the SAP-ISU system, supervisory control and data acquisition system, GIS and OMS. Another key communication technology used by TPDDL is automated meter reading, through which meters of more than 50,000 consumers are connected on its network.

In addition, any time payment and spot billing machines are an important part of the communications infrastructure. Different modules of SAP have also been implemented across several verticals such as human resource and finance. Two data centres of the utility are connected through servers so that secondary data centres can be used as a fallback option with the help of remote terminal units in case of an application failure at the primary data centre.

Choice of connectivity

TPDDL’s 350 km fibre network comprises a mix of leased fibre from service providers, optic fibre cable (OFC) network as well as an optical ground wire system. Further, over 180 locations (including grid substations, district offices and zonal cash collection centres) are connected through OFC, radio frequency (RF), GSM and general packet radio service technologies.

The company’s communications network has a core-ring with a capacity of STM 16 or 2.4 GHz and both its data centres are on this network. The sub-rings have a capacity of STM 4 and data from these merges with the core-ring. The communications network consumes around 400 Mbps of bandwidth for various applications. RF connectivity technologies are also being used in the communications network. In case of a fibre cut, data is transmitted through 100 Mbps microwave links between adjacent sub-rings.

Design and performance requirements

According to Sanjeev Kumar Rana, senior manager, Smart Grid Group, TPDDL, “The strength of a communications network can be assessed based on several parameters.” One of the important performance requirements for any communication technology is network availability. The amount of time the network is available for use (along with other performance parameters) should be stated in the service level agreements signed with telecom service providers. Another performance requirement is network latency, which can be measured in terms of response requirement and data rate requirement. Further, a communications network should be able to support the quality of service provisioning mechanisms, that is, control mechanisms which can provide different service qualities or priorities to various users. By incorporating all these factors TPDDL has been able to establish a strong ICT infrastructure.

Based on a presentation by