Substations and switchgear play a vital role in providing reliable supply. As such, various government schemes have been formulated in India for network strengthening and modernisation in the transmission and distribution segment. The focus of some of these programmes, such as the Integrated Power Development Scheme (IPDS) and Deendayal Upadhyaya Gram Jyoti Yojana (DDUGJY), is on setting up new substations and augmenting the existing ones across distribution utilities in the country. Under DDUGJY, work (including augmentation) has been carried out on 7,179 substations as of December 2021. Meanwhile, under the IPDS, as of February 2022, 991 new substations have been commissioned, and 1,601 have been augmented. Further, the recently launched Revamped Distribution Sector Scheme (RDSS) aims to focus on distribution infrastructure works. Transmission utilities have also been focusing on the expansion of substation capacity to further strengthen the network and enable greater integration of renewable energy. During 2021-22, 78,982 MVA of substation capacity was added by transcos across the central, state and private sectors, vis-à-vis 57,575 MVA in the previous year (at the 220 kV and above level).
Under the IPDS and DDUGJY, distribution utilities have undertaken significant substation capacity addition, as well as augmentation. The IPDS was launched in November 2014, with the aim of increasing the quality and reliability of power supply in urban areas. In terms of financial outlay, a total project cost of Rs 310.74 billion has been sanctioned under the IPDS. Key components of the scheme include strengthening of sub-transmission and distribution networks in urban areas; metering of feeders, distribution transformers and consumers; enterprise resource planning (ERP) and information technology (IT) enablement; provisioning of solar panels and underground cabling; gas-insulated switchgear (GIS) substations at locations with space constraints; and real time-data acquisition system (RT-DAS) projects for accurate measurement of power interruption parameters such as System Average Interruption Duration Index/ System Average Interruption Frequency Index at the 11 kV feeder level. Component-wise, around 91.7 per cent of the sanctioned cost is for system strengthening. Projects covering 547 circles in 33 states/union territories are part of the scheme. Of these, system strengthening works in 546 circles have been successfully completed. Apart from this, Rs 17.65 billion has been earmarked for IT and operational technology projects (such as IT-enablement of towns, ERP, RT-DAS and smart meters) and Rs 8.14 billion for new technologies (such as GIS substations). Since the launch of the IPDS, till February 2022, 991 new substations have been commissioned. Further, capacity augmentation has been carried out at 1,601 existing substations. For GIS substations, the total approved project cost, including the project management agency cost, is Rs 8.14 billion. The total grant approved by the central government is around Rs 5.3 billion, of which Rs 4.5 billion has been released.
Meanwhile, the DDUGJY, launched in December 2014, has been focusing on strengthening sub-transmission and distribution networks in rural areas. The key objectives of the scheme include network strengthening, metering, rural electrification, feeder segregation and decentralised, distributed generation. The scheme’s network strengthening plans entail the installation of new substations and augmentation of transformer capacity at existing substations. To this end, the DDUGJY covers the setting up of 2,816 new substations and capacity augmentation of 4,407 substations. As of December 2021, work (including augmentation) has been carried out on 7,179 substations.
Further, a key component of the RDSS is distribution infrastructure works, required for strengthening and modernising the system as well as for loss reduction. The infrastructure strengthening works will include the construction of new substations and upgradation of existing ones, among other projects. The scheme has a total outlay of Rs 3,037.58 billion, with an implementation timeline of five years (financial year 2021-22 to financial year 2025-26). Funding for substations under the scheme will be as per requirement. The scheme also plans to fund 3,875 supervisory control and data acquisition projects to enable real-time supervision and controllability of substations, including opex for two years, besides other works.
In 2021-22, of the total substation capacity addition, the maximum capacity of 39,095 MVA was added by Power Grid Corporation of India Limited (Powergrid), as per the Central Electricity Authority. Other utilities that added significant capacity during the year include Transmission Corporation of Telangana Limited (9,248 MVA), Uttar Pradesh Power Transmission Corporation Limited (UPPTCL) (5,740 MVA), Gujarat Energy Transmission Corporation Limited (GETCO) (5,180 MVA), Karnataka Power Transmission Corporation Limited (2,850 MVA) and Madhya Pradesh Power Transmission Company Limited (2,065 MVA).
At the interstate level, Powergrid has a projected capex of around Rs 300 billion, to be incurred in the next three years. The various transmission projects in hand include ongoing regulated tariff mechanism (RTM) projects worth Rs 71 billion, new RTM projects worth Rs 312 billion, and tariff-based competitive bidding (TBCB) projects worth Rs 132 billion. Currently, projects worth Rs 257.5 billion are under bidding via TBCB, including interstate transmission system (ISTS) projects under bidding (Rs 129 billion), ISTS projects for which bidding is yet to be initiated (Rs 108 billion) and intra-state projects under bidding (Rs 20.5 billion). At the intra-state level, most state transcos have not firmed up substation capacity addition plans. Among the utilities for which substation capacity addition plans are available for the next three to four years, the maximum substation capacity is planned by Tamil Nadu Transmission Corporation Limited, GETCO, UPPTCL and Jharkhand Urja Sancharan Nigam Limited.
Key developments include the recent commissioning of the first GIS substation in Pulwama’s Lassipora area by the Jammu and Kashmir Power Development Department, which has given a boost to electricity supply. Further, Tata Power Delhi Distribution Limited has installed a 630 kVA submersible transformer under the parking space of its substation building in Gujranwala Town in New Delhi. It is the first submersible distribution transformer set up by a utility in India, installed in collaboration with Toshiba Transmission and Distribution Systems (India) Private Limited. It is virtually a zero-space installation, as the top surface can be used for general purpose applications such as walkways, roads and parks.
The way ahead
Overall, the implementation of various schemes has led to an improvement in the transmission and distribution segment through the expansion and augmentation of networks. Going forward, under the RDSS, each discom/ state will draw up a scheme according to its requirement, with the end objective of reducing losses and ensuring 24×7 power supply. N