Transformers convert electrical energy from one voltage level to another. They are essential in the electricity network. After generation in power stations, electrical energy is transported to areas where it is consumed. This transport is more efficient at higher voltage, which is why power generated at 10 – 30 kV is converted by transformers in to typical voltages of 220 kV up to 400 kV, or even higher.
Since the majority of electrical installations operate at lower voltages, the high voltage needs to be converted back close to the point of use. The first step down is transformation to 33 – 150 kV. It is often the level at which power is supplied to major industrial customers. Distribution companies then transform power further down to the consumer mains voltage.
In this way, electrical energy passes through an average of four transformation stages before being consumed. A large number of transformers of different classes and sizes are needed in the transmission and distribution network, with a wide range of operating voltages.
Large transformers for high voltages are called system transformers. The last transformation step in to the consumer mains voltage is done by the distribution transformer.
On the policy front
Promotion of energy-efficient transformers through a number of policy instruments, including Minimum Energy Performance Standards (MEPS), are the most powerful tools to shift the entire market to higher levels of efficiency and ensuring realisation of national benefits of cost-effective energy. The Bureau of Indian Standards (BIS) has revised and published the National Standard for Distribution Transformers (DTs), IS 1180 (Part-I). This comprehensive standard has extended the scope for covering the entire range of DTs, i.e. up to 2500 kVA and 33 kilovolts, bringing India’s coverage more in line with other major economies such as Australia, China and the United States.
India has adopted a mandatory labelling scheme launch by Bureau of Energy Efficiency (BEE) for specific types of liquid-filled, naturally air-cooled three-phase distribution transformers. It covers power ratings up to 200 kVA. Power utilities were mandated to procure at least a 3-starred distribution transformer. BEE is in the process of reviewing and enhancing the scope up to 2500 kVA.
Specifications for procurement of high efficiency transformers for new installations and replacements and government policy initiatives like the Energy Conservation Act, implementation of 12th Five Year Plan and Rural Electrification Programmes, will drive the transformer market.
The author is Chief Manager –
Sustainable Energy, International
Copper Association India (ICA India).