A new interstate transmission system (ISTS) scheme is in the making, aimed at providing redundant ISTS power supply to upcoming manufacturing units in the Dholera Special Investment Region (SIR) in Gujarat.

The proposed transmission scheme will be a second power source, in addition to the 220/33kV Dholera substation along with the 400kV double-circuit Panchham—Dholera line  already established by state transmission utility Gujarat Energy Transmission Corporation Ltd (GETCO).

Under the new scheme, around 150-200 MW of power will be drawn from the upcoming ISTS Vataman substation and fed to GETCO’s new substation at Dholera (called Dholera-2), which is 30-35 km from Vataman.

It may be mentioned that the 765kV Vataman switching substation is being implemented as part of an ISTS scheme developed by Vataman Transmission Ltd, a wholly-owned subsidiary of Power Grid Corporation of India Ltd (PGCIL).

The Vataman substation is envisaged for completion by December 2025 and GETCO is seeking ISTS connectivity to its Dholera-2 substation by January 2026.

Two-pronged project

The proposed ISTS scheme, to be known as “Transmission system to provide redundant power supply to Dholera area” will have two components.  Under the first, some elements that are already envisaged under another ISTS scheme “Transmission system for offshore wind in Gujarat,” will be transferred to the present Dholera scheme. The second component will involve development of new transmission elements.

The first component will entail creation of a 400kV switchyard along with installation of 2×1500 MVA, 765/400kV interconnecting transformers at the Vataman (AIS) substation.

It may be carefully noted that the Gujarat offshore wind transmission project involves capacity augmentation of the Vataman substation that is coming up through Vataman Transmission Ltd. Some elements of this augmentation have now been shifted to the Dholera transmission project as they would need to be commissioned sooner.

The second component involves development of a 220kV switchyard along with installation of 2×500 MVA, 400/220kV interconnecting transformers (ICT) at the Vataman substation and two 220kV line bays for the 220kV double-circuit line from Vataman substation to GETCO’s Dholera-2 substation. The 220kV line, itself, will be implemented by GETCO and will not be part of the Dholera ISTS scheme.

Space for the additional infrastructure envisaged at the upcoming Vataman substation will be provided by Vataman Transmission Ltd.