Building System Resilience

Network modernisation key to robust T&D operations

The strengthening and modernisation of transmission and distribution (T&D) networks is imperative for maintaining uninterrupted power supply and quality. With greater integration of renewables and diverse loads like electric vehicles (EVs) as well as distributed generation, T&D networks need to be resilient to deal with exigencies and prevent blackouts. A case in point is the Mumbai grid outage in October 2020, which affected nearly 18.4 million residents in the city and its suburbs and was reportedly triggered due to tripping of a key transmission line. This points to an enhanced need for operations and maintenance (O&M) as well as remote monitoring of critical assets. Indian T&D utilities are undertaking several initiatives to modernise the grid and adopt the latest technologies.

Power Line presents an account of key initiatives and programmes in the T&D segment on this front…

Distribution network modernisation

Network modernisation and strengthening in the distribution segment is mainly being carried out under the central government schemes. Given the weak financial health of the state-owned discoms, these schemes are helping discoms adopt latest technologies such as smart meters, distribution automation as well as augment the power supply infrastructure. The central government’s twin flagship programmes – the Integrated Power Development Scheme (IPDS) and the Deendayal Upadhyaya Gram Jyoti Yojana (DDUGJY), which were launched in 2014, are at the core of the Ministry of Power’s (MoP) attempts to ensure 24×7 power for all and strengthen the distribution segment in urban and rural areas respectively.

With an investment outlay of Rs 320 billion, the IPDS targets strengthening of the sub-T&D networks, digitalisation including IT enablement of discoms, enterprise resource planning (ERP) and smart metering, substation monitoring and gas-insulated switchgear (GIS) substations. Notably, system strengthening has the highest share (88 per cent) in the total approved project cost at Rs 282 million. Meanwhile, IT enablement, ERP, smart metering, real-time distribution automation system (RT-DAS), and GIS substations have a share of 1-3 per cent each. So far, projects worth over Rs 2 billion has been sanctioned for RT-DAS for 35 discoms, ERP projects have been approved for 18 states and 102 GIS substations have been approved for 16 states. Further, 20 data centres, 20 disaster recovery centres and 44 customer care centres have been completed under the IPDS.

As per an IPDS impact assessment study by the MoP covering 250 towns under 46 discoms, 43 discoms reduced aggregate technical and commercial (AT&C) losses. Around 220 towns showed a reduction in AT&C losses with respect to baseline values. In fact, 109 sample towns reached a level of 15 per cent AT&C losses. The reduction in AT&C losses resulted in a saving of about 12,000 MUs of electricity (worth Rs 30.52 billion) in terms of the power procurement cost.

Similarly, the DDUGJY, with an outlay of over Rs 576 billion (including an additional outlay under the Saubhagya scheme), targets the electrification of all villages and strengthening of sub-T&D infrastructure in rural areas and feeder separation, among other things. Massive system strengthening has been undertaken under the scheme so far in rural areas with the establishment of nearly 660,000 ckt. km of 11 kV lines and about 1.27 million ckt. km of low tension lines. Further, over 2,600 new substations have been set up and 4,214 substations have been augmented under the scheme.

Another key network modernisation initiative is the National Smart Grid Mission (NSGM), which was launched in 2015. So far, 11 pilot smart grid projects, which were launched in 2013 by the MoP, have been declared go-live, approximately 156,000 smart meters have been installed and eight projects have reached financial closure. The Assam, Tripura and Telangana projects are expected to achieve financial closure by December 2020, for which impact assessment has been completed. Some of the key findings from these projects are that six pilots exceeded their AT&C loss targets, smart grid systems have been integrated with the R-APDRP in the Tripura, Assam and West Bengal pilots, and remote connect/disconnect has been tested at all pilots. Further, two smart grid projects in Bilaspur and Raipur, being developed by Chhattisgarh State Power Distribution Company Limited, are currently under consideration.

Apart from this, five smart grid projects have been sanctioned to cater to 810,000 consumers, and are at various stages of development. Around 750,500 smart meters are expected to be installed as part of these five NSGM projects being carried out in Chandigarh, Jharkhand, Odisha and Rajasthan. As of November 2020, the projects being implemented by the Chandigarh Electricity Division (CED), excluding subdivision-5, Jharkhand Bijli Vitran Nigam Limited and Odisha Power Transmission Corporation Limited are at the tendering stage, while projects in CED subdivision-5 and Jaipur Vidyut Vitran Nigam Limited are under implementation. The projects entail deployment of automated metering infrastructure, distribution transformer monitoring units, ERP as well as Supervisory control and data acquisition system.

Further, Energy Efficiency Services Limited (EESL) is implementing the Smart Metering National Programme with an objective to replace 250 million conventional meters with smart meters. So far, nearly 1.4 million smart meters have been installed by EESL. Key states include Uttar Pradesh (984,000 smart meters), Haryana (123,000), the New Delhi Municipal Council area (57,000) and Bihar (28,000).

Technology trends in transmission

Digital substations, greater penetration of flexible AC transmission systems to manage the growing share of renewable energy generation, energy storage systems and the use of data analytics and artificial intelligence (AI) to increase the efficiency of grid resources are some of the growing technology trends in transmission. The country’s premier transmission utility, Power Grid Corporation of India (Powergrid) is introducing new technological developments in the interstate transmission segment and is actively working in these areas.

The company has set up the National Transmission Asset Management Centre (NTAMC) at Manesar, near Gurugram, Haryana, and regional transmission asset management centres (RTAMCs) at various locations across the country, which are manned round the clock by experts for effective monitoring and management of assets. These state-of-the-art centres have been facilitating remote operation of the system and monitoring of various parameters on a real-time basis, at regional and national levels. During the year 2019-20, 24 substations were integrated with the NTAMC for remote operation, taking the total substations that are being operated remotely to 234. Powergrid also established its 11th TAMC at Bhubaneswar (Odisha) in 2019-20.

Powergrid has also installed a number of state-of-the-art static synchronous Compensators (STATCOMs) in the 400 kV grid to improve the grid reliability and voltage stability limit. The company has commissioned STATCOMs at Solapur, Aurangabad, Satna and Gwalior in the western region; Lucknow and Nalagarh in the northern region; Ranchi, Rourkela, Jeypore and Kishanganj in the eastern region; and Udumalpet, Trichy, Hyderabad and NP Kunta (in Ananthapuram) in the southern region. In addition, Powergrid has implemented pilot projects on process bus technology at the Bhiwadi and Neemrana substations and is in the process of implementing it on the upcoming 220/66 kV GIS substation project at Chandigarh.

Further, in a bid to move towards smart transmission, Powergrid is implementing  a wide area measurement system-based unified real time dynamic state measurement project for real-time monitoring of grid parameters. Cumulatively, 1,379 phasor measurement units for 329 stations and 31 phasor data concentrators for the National Load Despatch Centre (NLDC), NTAMC, all regional load despatch centres (RLDCs) and 24 state load despatch centres (SLDCs) had been commissioned till March 2020.

Moreover, in order to support the integration of renewables into the grid, 11 renewable energy management centres (REMCs) were commissioned in March 2020. REMCs allow centralised forecasting and monitoring of renewable energy generation and have been set up by Powergrid under the central government’s flagship Green Energy Corridors I project. REMCs are also equipped with AI-based renewable energy forecasting and scheduling tools, which provide better visualisation and situational awareness to grid operators. These 11 REMCs are co-located with the NLDC, SLDCs in Tamil Nadu, Karnataka, Andhra Pradesh, Maharashtra, Madhya Pradesh, Gujarat and Rajasthan, and RLDCs in Bengaluru, Mumbai and New Delhi.

The way forward

Some of the upcoming technology and modernisation initiatives in the power sector are mainly in the areas of digitalisation and cloud computing, cybersecurity, peer-to-peer trading based on blockchain, augmented reality/virtual reality-based O&M and digital twins, among others. Going forward, network modernisation measures will play a key role in building a resilient smart grid of the future.

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