WBSETCL: Focused efforts to enhance transmission system reliability

Focused efforts to enhance transmission system reliability

West Bengal’s sole state transmission company, West Bengal State Electricity Transmission Company Limited (WBSETCL) is one of the largest transcos in India. It is responsible for transmitting power throughout the state. In recent years, WBSETCL’s efforts have been focused on enhancing the reliability of the transmission network system, reducing transmission losses and voltage fluctuations, and making intra-state electricity transmission efficient through the provision of a competent electricity transmission network, construction of new substations including air-insulated substations (AIS) and gas-insulated substations (GIS), capacity augmentation of existing substations and reactive power management to ensure a robust grid. For the period 2019-20 to 2024-25, the transco has outlined a massive capex of Rs 80.82 billion, of which the majority is expected to be incurred on new transmission lines and substations.

Current network and operational performance

WBSETCL was incorporated in April 2007, post the unbundling of the erstwhile West Bengal State Electricity Board (WBSEB), in line with the requirement under the Electricity Act, 2003. The erstwhile WBSEB was unbundled into WBSETCL and West Bengal State Electricity Distribution Company Limited.

As of January 2020, WBSETCL’s total transmission line length stood at 14,710.7 ckt. km, 4.6 per cent higher than its line length of 14,060 ckt. km in 2018-19. The transmission line length registered a compound annual growth rate (CAGR) of 3.95 per cent during the period 2014-15 to 2018-19. Around 58.32 per cent (8,579.4 ckt. km) of its network is at the 132 kV level, 25.48 per cent (3,748.5 ckt. km) is at 220 kV, 13.93 per cent (2,049.8 ckt. km) is at 400 kV and the remaining (333 ckt. km) is at the 66 kV level. A line length of over 600 ckt. km was added during 2019-20 (till January 2020) as against 461 ckt. km in 2018-19. During 2019-20, the maximum line length of 82 per cent was added at the 132 kV level, followed by 15 per cent at 400 kV and 3 per cent at 220 kV.

As of January 2020, WBSETCL owned 141 substations (including AISs and GIS       ) and 651 transformers. One new AIS substations (220 kV) and three GIS substations (one at 220 kV and the other two at 132 kV) were added in 2019-20 (till January 2020). In 2019-20 (till January 2020) eight transformers were added, of which three were at the 220 kV level and five at the 132 kV, level. Meanwhile, WBSETCL added 1,448.3 MVA of transformer capacity in 2019-20 (till January 2020) as compared to 2,679 MVA of transformer capacity added during 2018-19. As of January 2020, its total transformer capacity stood at 35,291 MVA.

WBSETCL’s transmission losses have remained below 3 per cent over the past few years and decreased from 3.12 per cent in 2014-15 to 2.49 per cent in 2018-19 and 2.62 per cent in 2019-20 (as of January 2020). The company’s normative system availability stood at 99.92 per cent during 2018-19 and 99.85 per cent as of January 2020. In the 2019 fiscal, WBSETCL handled about 53,319 MUs of energy on its transmission network as against 49,560 MUs in the 2018 fiscal.

Financial highlights

WBSETCL has consistently delivered good financial performance in recent years. In terms of total revenue, the company registered a growth of 5.67 per cent in 2018-19 over the previous year. The total revenue went up from Rs 13.49 billion in 2017-18 to Rs 14.26 billion in 2018-19. Since 2014-15, the company’s total revenue has increased at a CAGR of 7.98 per cent. It recorded a net profit of Rs  4.48 billion in 2018-19, witnessing an increase of 2.32 per cent over the previous year. Since 2014-15, the company’s net profit has grown at a CAGR of 13.59 per cent. Its total expenditure increased by 3.31 per cent in 2018-19 over the previous year to stand at Rs 9.1 billion. The operations and maintenance cost increased from Rs 641.8 million in 2017-18 to Rs 661.8 million in 2018-19, registering a growth rate of 3.11 per cent. The transco’scapex recorded a CAGR of 6.23 per cent from 2014-15 to 2018-19 to stand at Rs 9.4 billion.

Future plans

The transco plans to add 13,806.5 MVA of transformer capacity from 2019-20 to 2024-25 to reach 46,368.5 MVA by 2024-25. It aims to add 5,371 ckt. km of line length over the same period to reach a line length of 19,431 ckt. km by 2024-25. It also plans to increase its GIS base to 83 by 2024-25.

WBSETCL has planned a sizeable capex of Rs 80.82 billion for the period 2019-20 to 2024-25. Of this, the maximum amount is planned for the construction of new transmission lines and substations (Rs 63.64 billion), followed by renovation and modernisation (R&M)/augmentation of existing assets (Rs 15.61 billion), and IT/SCADA and software (Rs 0.88 billion). The highest capex of over Rs 15 billion is expected to be incurred in 2021-22.

One of the key ongoing projects of the transco is reactive power management of the state grid. It plans to undertake the installation of 33 kV capacitor banks at 36 EHV substations to improve the power factor and the system voltage profile, and reduce the transmission loss. Also, to control and overcome high voltage problems in the eastern regional grid, the installation of a 125 MVAr switchable bus reactor has been planned at the Arambag 400 kV substation. Around 90 per cent of the project cost will be provided by the Power System Development Fund as a grant.

Some of the other important projects that are currently under way are R&M of the transmission system for relieving congestion in the intra-state transmission system, installation of switchable reactors at 400 kV and shunt capacitors at 33 kV, and establishment of reliable communication and data acquisition systems at WBSETCL’s substations. The implementation of an integrated system for scheduling, accounting, metering and settlement of transactions (SAMAST) has also been planned in West Bengal for Rs 259.6 million.

In September 2019, GE T&D India Limited secured a Rs 900 million grid upgradation order from WBSETCL. The order involves the construction of three new 132/33 kV substations using GE’s GIS technology in Ramnagar, Manbazaar and Birlapur. It also includes the extension of three existing substations at Hurand, Sirakole and Indus by adding two bays each.

With regard to the interstate transmission system, central transmission utility (CTU) Power Grid Corporation of India Limited (Powergrid) has one 800 kV HVDC and one 400 kV substation at Alipurduar, and four 400 kV and three 220 kV substations for the evacuation of power from central sector generators including power from Bhutan. Currently, about 400 MW of power can be received from the CTU in the state. Further, to provide sustainable power supply and facilitate power exchange with neighbouring states, the Central Electricity Authority has approved the construction of two 765 kV substations under tariff-based competitive bidding (TBCB) at Midnapur and Jeerat under the regional scheme. For the development of this project, PowergridMidnapur-Jeerat Transmission Limited has obtained the letter of intent through the TBCB route and the project is planned to be completed by 2021-22.


In sum, West Bengal’s transmission segment seems well positioned to cater to the changing sector needs with significant network additions planned in the near future. WBSETCL’s planned capex and initiatives are expected to ensure that it is on a strong footing to provide stable and quality power with improved availability and minimum losses in the transmission system.