Delhi discoms relying on advanced tech transformers to ensure power supply

The power discoms operating in Delhi are relying on their advanced-technology transformers to ensure an uninterrupted supply of electricity, with the peak demand ranging around 8,000 MW amid a scorching heatwave in the city.

The transformers used by the BSES are designed to operate at 40 degrees above the ambient (area) temperature, said a spokesperson of the company.

"This basically means that the transformers can operate at up to 40 degrees more than the prevalent area temperature. For example, if the area temperature is 48 degrees Celsius, these can operate till 88 degrees Celsius without any external aid," he said.

The BSES discoms (distribution companies) -- BSES Rajdhani Power Limited (BRPL) and BSES Yamuna Power Limited (BYPL) -- supply electricity to most parts of the city except North Delhi.

"Due to the modern design and technology, there is no need for any external aid like a fan to cool the transformer," the BSES spokesperson said.

Transformers getting overheated and burnt due to extreme temperatures leads to power outages for hours.

In some extreme cases, if the transformer temperature goes beyond 88 degrees Celsius, an external cooling fan is used to bring the temperature within the permissible limits, the BSES spokesperson said.

The Tata Power Delhi Distribution Limited (TPDDL) discom that supplies electricity to North Delhi operates 88 grid substations at the 66-KV and 33-KV level with 222 transformers, all remotely monitored and controlled through a central Supervisory Control and Data Acquisition (SCADA) system, said a spokesperson of the company.

"With the mercury soaring to extremes this summer, maintaining the optimal performance of our power transformers is crucial to ensure their effective functioning," she said.

Delhi recorded its highest-ever peak power demand of 8,302 megawatt on Wednesday as the city recorded a maximum temperature of 46.8 degrees, the highest in 79 years.

On Thursday, the maximum temperature was 45.6 degrees Celsius and the peak power demand was 8,091 MW at 3:28 pm. The weather department has forecast a maximum temperature of 44 degrees Celsius for Friday.

The TPDDL transformers are meticulously designed for diverse seasons and Delhi's environmental conditions, the spokesperson said.

The transformers are equipped with an "Oil Natural Air Natural" (ONAN), "Oil Natural Air Forced" (ONAF) cooling system that keeps their temperatures within the permissible limits during summer, she said.

An automatic cooling system activates or deactivates the cooling fans or oil pumps based on the transformers' oil temperature and winding temperature.

Remote monitoring through the SCADA system allows keeping a close watch on the oil and winding temperature indicators, she added.

Additionally, there is an arrangement of industrial blowers, strategic load shifting and sharing between transformers to avoid overheating issues.

Online monitoring, including thermos-scanning and ultrasonic testing, also ensures that the transformers are in peak condition even during the most demanding times, the TPDDL spokesperson said.