Distribution transformer market is expected to remain growth-oriented

In an interview with EPR Magazine, Chhaya Bhonslay, Chief – Technical Services (T&D), Tata Power, elaborates on the technology trends in distribution transformers.

What are the new technologies in distribution transformers? How is the technology evolving in the market?
While conventionally distribution transformers are oilfilled, safety and environmental aspects are now driving utilities to rely on dry transformers for distribution applications. Nowadays, regulatory agencies are also insisting for adopting dry type transformers for residential and commercial premises application. Another challeng for utilities in large urban cities is availability of space. As a result, most of the utilities are now installing dry type transformers in consumer substations and locating transformers in basement or even in high rise towers. Tata Power has recently successfully commissioned dry type transformer at 44th floor of a high-rise tower in Mumbai. Additionally, use of conventional mineral oil in transformer is being reviewed amidst raising concerns of environmental issues. K class fluids such as ester oil (natural or synthetic) are being offered as a very good alternative. Use of ester oil is no more limited to only larger capacity (> 5 MVA). Mumbai distribution typically involves highly concentrated load centres where transformer size ranges from 630 kVA onwards up to 1,500 kVA and 2,000 kVA. Application of natural easter, in place of conventional mineral oil, in such distribution transformers in Mumbai is being implemented since last 2-3 years by Tata Power. We have also tried natural esters for retrofitting the existing transformers and the performance at acceptable levels
has been observed.

High capital cost of synthetic ester oil is prohibiting its widespread application as of today. However, we expect the cost to come down in the next few years to facilitate its large-scale application.

Recently, Tata Power commissioned India’s largest 125 MVA natural ester filled transformer in Mumbai.

Amorphous core with optimised coil design and aluminium windings (for small distribution transformer application has potential applications in future for reducing losses and capital cost.

Technology for foil type winding instead of conventional conductor winding is already in practice for industrial applications, which can give advantage of more mechanical strength and may give some advantage of cost optimisation. For utility segment, this is now gaining momentum.

Reliable power output and minimum T&D losses make power sector stronger. What kind of automated and digital solutions will help achieve this?
Distribution network is generally spread across large geographical area. Remote monitoring and operation of such network is very crucial to ensure reliable supply. Such remote operation involves controlling switching operations of RMUs and switch gears as well as asset monitoring of all equipment in a substation. Establishing communication link to a substation in transmission network is relatively easy as FOP solutions are easily available while laying transmission network. However, for distribution network it poses a challenge in view of sheer numbers of substations involved.

GSM technology is presently being used wherever FOP network is not available. Optimisation of available network services is now being tried by deploying Dual SIM Modem as multiple mobile network services are now available in city like Mumbai. We are operating our Mumbai distribution network at benchmark reliability level (in terms of SAIDI & CAIDI) with automation level of about 44 percent, and with DAS availability of around 96 percent.

Use of long-range radio device (LORA) is now picking up for monitoring of nonautomated substation at optimal cost. We have already deployed this technology at more than 100 substations in Mumbai and integration of the same with existing Distribution Management System (DMS) is in final stages.

The above techniques supplemented with intelligent data analytics techniques facilitate for effective distribution grid management, which in turn supports minimisation of losses and stable and reliable distribution supply to all customers.

How are the state DISCOMS and government agencies responding to the concept of digital transformers?

Transformers are very critical equipment in the Transmission & Distribution networks. Hence, reliability and availability of these transformers is vital to meet customer service requirements. Digital transformers with various sensors provided for online monitoring of asset health provide early detection signal and thus help in taking necessary corrective actions to prevent failures.

These online diagnostic applications are gaining popularity for large power transformers in transmission area but its commercial viability is still a concern for distribution area. DISCOMS are exploring these concepts actively, by balancing among capex costs, ARR approvals and the technology benefits.

What is the current market size of distribution transformers in India? What is the growth trend?
Transformer market in India is growing rapidly in last few years. It is estimated that complete transformer market in India may reach more than Rs 80,000 crore per year by FY 22, out of which, the power transformers contribute 45 percent, and distribution transformers 55 percent.

There are large number of manufactures in the range of 200- 250 in numbers in distribution transformers. However, the quality of manufactures differs vastly on account of being national and international level OEM or small-scale unorganised OEMs. The vast difference can be seen by the fact that out of these total manufacturers, there are just about 5-8 per cent constitute national and international level OEMs. The rest of the manufactures are from small-scale sector.

These small size players enter through State Electric Boards (SEBs) where price-sensitive L1 criteria plays a dominant role. This is directly affecting the quality of product, which can be seen by failure rate of transformers in SEBs. There is growing need to shift the policies of SEBs from lowest cost of supply to optimisation of lifecycle cost assessment.

How do you look at the future of distribution transformer market?
Distribution transformer market is expected to remain growth-oriented with the following key drivers and opportunities for growth:
• Government’s focus on rural electrification
• Increasing focus on distribution reforms and privatisation of utilities in India is expected to drive network upgradation in distribution segment
• Growth in renewable capacities will require strengthening of T&D infrastructure
• Expected industrial growth in India will lead to load growth requiring network upgradation
• Replacement of ageing equipment in distribution area Key challenges to be addressed are poor financial condition of SEBs and political will for driving distribution reforms.

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Digital transformers with various sensors provided for online monitoring of asset health provide early detection signal and thus help in taking necessary corrective actions to prevent failures.” – Chhaya Bhonslay, Chief – Technical Services (T&D), Tata Power