A total of 75 EHV transmission line masts in 22 transmission lines failed between January and June 2025 or the 1st half of 2025 due to multiple reasons that need to be checked and reported by the utility companies in a timely manner. File | Photo credit: S. Thanthoni
A government committee has ordered transmission companies, including those owned by the Adani Group and state-owned NTPC, to carry out proper maintenance as 75 high voltage (EHV) pylons failed between January and June 2025.
According to the meeting minutes of the committee, the change in wind intensity in certain parts of the country due to climate change has been observed as one of the key reasons for the failure of EHV transmission line masts, which play a key role in transporting large amounts of power over long distances.
A total of 75 EHV transmission line masts in 22 transmission lines failed between January and June 2025 or the 1st half of 2025 due to multiple reasons that need to be checked and reported by the utility companies in a timely manner.
These assets are owned by 12 players, including Adani Transmission, ReNew Transmission Ventures, Resonia Limited (formerly Sterlite Power Transmission Ltd), Powergrid and NTPC, according to a report by the Standing Committee of Experts set up by the Central Electricity Authority (CEA).
According to the report, the main cause of tower failures is attributed to high-intensity winds, according to transmission companies. Wind intensity has changed in certain parts of the country due to climate change. However, in many cases of EHV transmission line tower failures, utilities have failed to provide wind data that could support their reasoning.
Other reasons for the failure of EHV line masts include foundation damage, mast structure and deformation of the mast legs and lower level cage of the cross arm.
To avoid such incidents, CEA has advised utilities to refer to the wind map provided in the National Building Code while designing towers until the revised wind map is included in IS 875. SERC in coordination with IMD has been asked to update the wind map.
It said transmission companies must take proactive measures such as increased patrolling of the line and immediate replacement of missing members/bolts. Various deficiencies such as missing members, missing bolts, bent members, improper attachment of cross arm, soil covered chimney and rusted stubs/members were observed during the failure site visit of various transmission towers of various utilities.
Power companies should take necessary precautions and carry out proper maintenance of their lines to prevent towers from failing due to such deficiencies, he added.
Transmission towers built near river banks should be patrolled frequently and an assessment based on history should be made to anticipate changes in river flow and the towers should be provided with the necessary protection to prevent damage during such an event.
For towers located in overlapping wind zones, the panel recommended that the higher wind zone be considered if the tower is located within 50 km of the border area, and the tower can be designed accordingly.
The company also recommended that utilities develop their own teams equipped with appropriate tower design software to simulate, analyze and solve design problems for failed towers.
The CEA also recommended that digitization of spare parts and inventory management of transmission system assets using appropriate software such as SAP should take place on priority.
The power companies are also asked to submit the actual wind speed prevailing in the affected area so that the investigation team of the standing committee can get the reference wind speed that prevailed over the area. In this matter concerned power company may seek assistance from IMD/Nearest Airport/Nearest Wind Farm or State Irrigation Department to estimate the wind speed in the affected area based on observatory/satellite/radar data.
Energy companies should submit a report on the termination of the action, including all details and records, within 3 months. All utilities are required to strictly adhere to these timetables, he noted.
Published – 21 Oct 2025 20:57 IST
