Ensuring Transformer Efficiency

Key to reducing overall transmission losses

The Indian power sector has been facing mounting financial and technical losses. This can be attributed to the obsolete energy infrastructure and poorly connected transmission network in the country. As per a Power Finance Corporation report, transmission and distribution (T&D) losses stood at 21.81 per cent in 2015-16, a marginal decline from 22.77 per cent in 2014-15. Even though transformer losses account for a small share of the overall T&D losses, investing in better transformers can help improve the situation significantly.

Transformers are the first and most crucial links connecting the three power segments – generation, transmission and distribution. The entire quantum of electricity that is transmitted passes through the transformers. Research has indicated that transformers are the second largest loss-making equipment in electricity networks, after transmission lines. Therefore, it is important to ensure transformer efficiency and reduce the loss levels. High transformer losses at the intermediate levels reduce the energy output. As a result, more power is generated, leading to higher carbon emissions.

Need for efficient transformers

Studies indicate that over 3 per cent of the generated electrical energy is lost between the generating source and the end user due to transformer losses. Making amends at the transformer level could thus have a considerable impact on improving grid stability.

The majority of transformers in the country are inefficient as reflected in the high loss figures at the national level. Inefficient transformers result in a lower quantum of usable energy and high operations and maintenance costs. In addition, transformer failures can result in sudden outages, which, in turn, can affect a wide range of production activities in the economy. An efficient transformer is thus important to avoid such possibilities and ensure lower losses, improved reliability and a potentially longer service life.

To this end, one possible measure is to replace the current fleet of transformers with amorphous metal transformers, which are more efficient. Further, using a better grade of core material and making more turns in the coil could reduce non-load losses. Using copper instead of aluminium can also significantly reduce load losses. Research in this segment has indicated that deploying efficient transformers can reduce losses by as much as 60 per cent. Moreover, considering that efficient transformers last longer, even a longer payback period would yield significant monetary benefits. Hence, an efficient transformer is a lucrative option both from a financial and technical perspective.

Current scenario

Recognising the importance of efficient transformers in the power value chain, the government has introduced several measures and standards to ensure that good quality transformers are deployed by the concerned entities. In February 2015, the Bureau of Indian Standards introduced the revised standard IS 1180:2014, “Outdoor Type Oil Immersed Distribution Transformers up to and including 2,500 kVA, 33 kV – Specification Part-I Mineral Oil Immersed”. The revised standard was drafted to broaden the scope of coverage beyond the 200 kVA level up to the 2,500 kVA and 33 kV levels, and bring India’s efficiency norms on par with international standards. Further, the new standard incorporates losses at 50 per cent and 100 per cent loading. In addition, the Bureau of Energy Efficiency has a mandatory “star rating plan” in place that rates distribution transformers on a scale of one to five, with five-star-grade transformers being the most efficient. Total loss figures are stipulated both at 50 per cent loading and 100 per cent loading for each star classification. Apart from the efforts by the government, organisations such as the International Copper Alliance India (ICAI) have contributed to energy efficiency by conducting programmes on this subject. These programmes recommend the use of low-loss distribution transformers amongst other things. In the past, ICAI has also collaborated with the Indian Transformers’ Manufacturers Association for conducting conferences that promote the use of energy efficient distribution transformers.

Challenges and the way forward

Although the existing scenario indicates the need for advanced transformers, there are certain issues that need to be dealt with. The cost of these transformers remains the primary concern. While it is argued that the resultant savings would eventually offset the costs, the initial investment remains a major impediment. In addition, there are several standards and mandates for the deployment of transformers, but there continues to be a lack of uniformity in implementing these standards. Therefore, it is important to ensure that the entire country is woven into the same regulatory fabric.

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