With a view to including the planning and development of 1,150kV ultra-high voltage alternating current (UHVAC) power transmission systems, Central Electricity Authority (CEA) has newly released its “Manual on Transmission Planning Criteria, 2026”.
The newly-released manual, which takes effect from October 15, 2026, incorporates substantial revisions to its preceding versions. The “Manual on Transmission Planning Criteria” was first released way back in 1985 and was subsequently revised in 1994, 2013, 2023 and 2025.
The UHVAC focus
The latest edition of the manual further advances the transmission planning framework by incorporating planning parameters and criteria for 1,150kV transmission systems, thereby providing an additional technological option for high-capacity power transfer over long distances and for addressing emerging right-of-way (RoW) constraints.
The manual has also been updated to include provisions for bulk load integration and system models, along with typical parameters, for VSC-HVDC systems, wind and solar power plants, battery energy storage systems (BESS), various renewable energy technologies, STATCOMs and other emerging components of the power system.
The “Manual on Transmission Planning Criteria, 2026” is available on the official website of Central Electricity Authority (CEA) and may be accessed using this external link.
Overall scope
The planning criteria detailed in the manual is primarily meant for planning of interstate transmission system (ISTS), intrastate transmission system (InSTS) and dedicated lines, right down to the 66kV voltage level.
The manual covers the planning philosophy, the information required from various entities, permissible limits, reliability criteria, broad scope of system studies, modelling and analysis, and prescribes guidelines for transmission planning.
Applicability
The planning criteria detailed in the latest manual shall be used for all new transmission systems planned after October 15, 2026. The existing and already planned transmission systems may be reviewed with respect to the provisions of these planning criteria. Wherever required and possible, the new manual recommends planning of additional system to strengthen the existing system.
Planning margins
The manual recommends that new transmission system additions required for system strengthening may be planned keeping a margin of 10 per cent in the thermal loading limits of lines and transformers. Further, the margins in the interregional links may be kept as 15 per cent.
Featured photograph is for representation only