Author: PPD Team Date: 23/06/2025
Twelve Inter-State Transmission System (ISTS) projects have been approved by the Central Transmission Utility of India Limited (CTUIL), according to a recent office memorandum. These projects span the Western, Northern, and Southern regions and involve transformer augmentation, reactor additions, and bays for renewable energy (RE) evacuation.
Separately, the 43rd CMETS-NER (Central Monitoring and Evaluation Team for Transmission in North Eastern Region) meeting reviewed progress and approved augmentation plans in the North Eastern Region (NER).
Approved ISTS projects
1. Raigarh (Kotra): 765kV, 80MVAr spare reactor for Bus Reactor #2 (Rs 123.3 million).
2. Jaipur South (PG): 1×500 MVA, 400/220kV ICT (Rs 489.6 million).
3. Neemrana (PG): 1×500 MVA, 400/220kV ICT (Rs 489.6 million).
4. Lucknow (PG): 1×500 MVA, 400/220kV ICT with GIS and bus extension (Rs 871 million).
5. Bikaner-IV PS: Three 220kV bays for Furies Solren (300MW) and SJVN Green (500MW) (Rs 185.4 million).
6. Barmer-I PS: One 220kV bay for Anboto Solar (300MW) (Rs 61.8 million).
7. Nagarjunasagar (AP): 1×500 MVA ICT, reactor bay shifting, and bus work (Rs 576.6 million).
8. Nellore: Conversion of 80 MVAr fixed reactor on Vijayawada-Nellore line to switchable (Rs 27.7 million).
9. Tumkur (Pavagada) PS: Two 220kV bays for Ayana and ACME RE projects (Rs 125.4 million).
10. Kozhikode (Kerala): 1×500 MVA ICT with bay works and 110kV diversion (Rs 531.3 million).
11. Trivandrum (Kerala): 1×500 MVA ICT with tie bay and associated works (Rs 534.2 million).
12. Udumalpet (Tamil Nadu): Replacement of 315 MVA ICT with 500 MVA ICT (Rs 377 million).
CMETS-NER meeting outcomes
At the 43rd Consultation Meeting for Evolving Transmission Schemes in the North Eastern Region (held on 29 May 2025), CTU and regional stakeholders discussed ongoing and upcoming intra-state and ISTS-linked works. Key decisions included:
- Ziro (Arunachal Pradesh)
Under NERES-31, a 132/33kV, 31.5 MVA ICT will be added with associated outdoor GIS and 33kV indoor GIS bays. Implementation timeline: 24 months. - New substations at Koronu and Wakro
Proposed by DoP Arunachal Pradesh and agreed for implementation under intra-state mode.
- Koronu: 2×10 MVA, 132/33kV substation via LILO of Roing–Tezu ISTS line.
- Wakro: 2×10 MVA, 132/33kV substation via LILO of Tezu–Namsai ISTS line.
Target commissioning: 2027.
- Downstream system status
Many ISTS substations in NER (New Mariani, New Kohima, Nangalbibra) have pending downstream lines. These are under various stages—route survey, tendering, or awaiting funding. - Intra-state 400kV developments
New substations at Rangia, Khumtai, Sonapur (Assam), Surajmaninagar (Tripura), and Zhadima (Nagaland) are in progress. These include LILO of multiple ISTS lines and augmentation to GIS. - Bay space allocation
Several STUs have been allotted bay space at ISTS substations for terminating their new intra-state lines. Implementation is pending in many cases.