Power Grid Corporation of India Ltd (PGCIL) has been assigned a project for re-conductoring of existing 400kV lines in West Bengal, under the regulated tariff mechanism (RTM) framework.
A decision to this effect was taken at the latest meeting of the National Committee on Transmission (NCT) held last month.
The project, termed as “ERES-48: Jeerat-Rajarghat-Subhasgram reconductoring,” has an estimated outlay of around Rs.212 crore and a completion timeframe of 30 months.
The project involves reconductoring of three existing 400kV single-circuit lines (Twin ACSR Moose) with Twin HTLS conductor, with ampacity of single HTLS as 1516 amp, spanning a total line length of around 140 ckm.
The three lines are:
- Jeerat (WBSETCL) – Rajarhat (PG) [41 ckm]
- Jeerat (WBSETCL) – Subhasgram PG) [65 ckm]
- Rajarhat (PG) – Subhasgram (PG) [34 ckm]
Besides, the project will entail commensurate upgrade of 400kV bay equipment at the three aforementioned substations in order to suit the HTLS conductor.
Rationale
Power demand and load growth in West Bengal is concentrated in the districts of North 24 Parganas and South 24 Parganas (including Kolkata). Currently, there are four main sources of power supply:
- 765/400kV New Jeerat substation (PGCIL)
- 400/220kV Jeerat substation (WBSETCL)
- 400/220kV Subhasgram substation (PGCIL)
- 400/220kV Rajarhat substation (PGCIL)
The aggregate transformation capacity of these four substations currently is 8,020 MVA and this would increase to 8835 MVA, after ongoing augmentations at Jeerat and Rajarhat are commissioned.
These four substations are currently feeding several 220kV and 132kV substations of state transco WBSETCL (West Bengal State Electricity Transmission Company Ltd) in and around Kolkata city. It is observed that there is currently no contingency provision for these lines and any outage would result in overload of remaining lines.
Further, WBSETCL has projected additional load to the tune of 200 MVA to 300 MVA for data centres in and around New Town and Rajarhat areas, with a 24×7 load profile.
To meet this load, WBSETCL has proposed to upgrade its existing 220/132kV New Town AA3 substation to 400/220/132kV. This upgraded substation will have ISTS connectivity via a LILO of the existing 400kV single-circuit Jeerat-Subhasgram line.
It is also found that the 400kV Jeerat–New Town AA3 and the Jeerat—Rajarhat lines are getting critically loaded under N-1 contingency. These lines, commissioned in 1986 and 1994, respectively, are sections of the 400kV 2xsingle-circuit Farakka—Jeerat line.
Considering the age of the lines, the RoW challenges and the critical role that these lines play to feed the capital city of Kolkata, it was decided that the entire 400kV section, which is Jeerat (WBSETCL)–Subhasgram (PGCIL), and Jeerat (WBSETCL) – Rajarhat (PGCIL) – Subhasgram (PGCIL), would be reconductored with HTLS conductor, under what is being called as the “ERES-48: Jeerat-Rajarghat-Subhasgram reconductoring” awarded to PGCIL under the RTM guidelines.
Commissioning schedule
The project is scheduled to commission in 30 months, aligned to the upgrade of WBSETCL’s 220/132kV New Town AA3 substation to 400/220/132kV, which is expected by March 2029.
Featured photograph (source: CTC Global) is for representation only