Transmission utilities have reported 17 cases of failure of power transformers of 220 kV and above voltage between January and June 2025, according to a report by the Central Electricity Authority (CEA).

The CEA observed that a large number of transformer failure incidents remain unreported, as many state and central transmission utilities and private utilities have failed to share data.

Transformers are the costliest equipment in a switchyard/substation. They are expected to serve the entire life of the substations, which is considered to be 35 years. “However, it has been observed that many transformers installed in Indian utilities have failed within the first few years of service, which is a matter of concern,” a CEA expert committee said.

Of the 17 failure incidents, the Maharashtra State Electricity Transmission Company alone reported nine transformer failures during the six-month period. In two cases, the utilities said the failed transformers were beyond repair.

The report attributed the transformer failures to normal aging, insulation system and bushing faults, frequent system faults, transient overvoltage generated by the system, and the absence of prudent maintenance practices.

Of the 17 incidents, six were of 220 kV class and 11 of 400 kV class transformers.

Six of the transformers failed within five years of operation, three between five and 10 years, five between 10 and 20 years, and three that were in operation for over 20 years.

In another report, the CEA reported that 76 extra high-voltage transmission line tower failures occurred across 28 transmission lines, including 220 kV, 400 kV, and 765 kV AC lines, in 2024.

The CEA noted that condition-based maintenance practices using modern diagnostic tools have yet to be adopted on a large scale by many utilities. The utilities must make it a practice to conduct various tests on major electrical equipment one or two months before the expiry of the equipment’s warranty period, so that any abnormality can be discussed with the equipment manufacturers for taking up remedial action.

India’s power transmission sector is facing challenges due to supply chain shortages and increased procurement costs, driven by high demand for transformers and other critical transmission components. Stakeholders report a growing stress in the power system supply chain, with shortages of transformers, control relay panels, tower parts, insulators, and gas-insulated switchgear. Longer lead times for procuring these components are delaying transmission projects.