Transformer sizing is very important in terms of overall economy as well as reliability of operation of a solar PV plant
Q.Could you elaborate on the importance of transformer sizing when planning a solar PV plant?
Transformers are used in solar PV plants to step up the output voltage of inverters thus playing a very important role in deciding the overall system configuration. Inverter Duty Transformer sizing in Solar Power Plant actually depends on the Inverter, which is sourced from Inverter manufacturers in India or abroad. As solar PV plants are getting MW and GW in sizes the requirements of larger inverters are growing in the market. Keeping with the demand a lot of reputed international manufacturers have started manufacturing higher capacity inverters in turn increasing the demand for higher sizing transformers. The specific advantage of using a higher sizing transformer is that it reduces the overall cable circuit cost in the electrical power circuit. In fact the overall electrical BOP cost comes down due to less number of HV circuit. The integration of power circuits helps cost reduction by 7 to 8 % on a typical 100 MW plant. The market has already observed stable source of 2 to 2.5 MW Central Inverters which if used twice per Transformers, can reduce lot of HV equipment. Transformer sizing is very important in terms of overall economy as well as reliability of operation. Indian EPC companies and Builders are gradually moving towards higher size Transformers of 4000 kVA to 6 MVA.
Q.Tell us more about the solar inverter duty transformer that Electrotherm manufactures? What makes it an ideal choice for solar pv plants?
We are manufacturing Solar Inverter duty Transformers since last 8 Years. We are probably one of the very few Indian companies that have commercially launched and establish 2 CCA design in Solar Inverter Duty Transformers. 2 CCA designs are preferable over 1 CCA designs because mechanically 1 CCA design becomes unstable after a particular capacity. For the last 3 to 4 years the average Transformer size has gone up due to continuous success and technology up gradation within the high capacity Inverter industry. The sizes of Central Inverters earlier were limited up to 1 MW, which has recently increased 2.5 folds helping more consolidation of loads per Transformers. Each Inverter is now able to handle excess currents as compared to earlier size of 1 MW max. The Transformer Industry has also designed Transformer size up to 10 MVA capacities, making it suitable for connecting to 4 such large Inverters.
Q.How does a Solar Power House help EPC contractor overcome the challenge of commissioning the project in record time?
Solar Powerhouse is an integral approach in terms of complete DC to AC conversion. In a Solar Power House, the Central inverters are connected to Transformers up to capacity of 4 MW AC. The Transformers HT side is then connected to the next compartment through busduct or cable for connection to HV switchgear. Several electrical main circuit and aux circuits including SCADA controls and battery bank are terminated and tested at factory before despatch to site. This reduces the site integration cost and time helping the project developers to commission the project in minimum time. Solar Power House being a plug and play model comes completely wired and integrated with equipments that are already tested making the integration of the device with the project at the site very easy.
Q.What sets apart the Solar Power House manufactured by Electrotherm from similar product available in the market?
Similar products available in market are either short in terms of capacity or in terms of efficient integration. Because we have technical expertise to address right from DC side of the Inverter circuit up to the HT VCB and Bushing connection in the field, we naturally stand apart in the crowd. The integrated test facility to check all protection and controls circuits with full load capacity is an added advantage in our case. Due to design and manufacturing superiority, we march ahead of others in terms of reliability and product quality. Our expertise in understanding the O&M also helps our customers to receive user friendly and easy to go equipment. Main circuit, Aux circuits and all other devices are well placed in the compact compartments and nicely segregated in terms of fault attending and monitoring purpose. The shortage of site experience is another fundamental which the other manufacturers lose which has emerged out to be one of the main reasons of their failures at the site. Competency in developing and designing of solar Power House is a key fundamental.
Q.How do you plan to achieve the target of supplying transformers worth 1200 MW solar capacity in the next 2 years? The segments those are likely to help in achieving the target?
We are at currently doing more than 1000 MW. The unit size has gone up, so we are making 15 to 20 Transformers per 100 MW as compared to earlier 40 Transformers for the same size plant. The Inverter supply should be smooth which will help developers to complete projects much faster.
Q.With solar capacity likely to double to 18GW this year, how do you see the sector contributing to the overall growth of the company?
As far as Solar Sector is concerned, we are focussing more on higher size Transformers and thus are able to comply to the growing market demand. Process control in Transformer manufacturing has been one of the key drivers in our facility; in fact this is a fundamental strength with our Brand. Till now we are able to respond to market Capacity and are able to grow in the sector while maintaining quality and timely delivery of products. We are able to honour commitments made to our customers in terms of commissioning schedule.
Q.How do you see the transformer technology changing over the next few years? How will this technology changes benefit the solar industry?
Technology has always been the key driver in the manufacturing of engineering goods. Transformers are no exception. However it is not much applicable to Solar Inverter Duty Transformers. The process has more or less remained same in the last 10 years. Till now, in India, we are following conventional manufacturing process as this is highly reliable and field tested. Of course; It is worth to mention here that some manufacturers are trying to develop Transformers using different raw material and using some modern process to cut down manufacturing cycle time to meet growing demand, however the technology is in the state of development and it will take time to meet the technical requirement of end product.
Q.In addition to the inverter duty transformer and solar power house, what are the other products manufactured by Electrotherm?
We are a leader in special duty Transformers since inception. We are pioneer in design, manufacture, supply, installing of Converter Duty Transformers required for Steel and Aluminium industry. There are high current Transformers with special cooling facility and works with several other electromechanical equipment for Heat Treatment and other requirement of heavy engineering and process industry .
Q.What role do you envision Electrotherm playing in the solar industry? Your vision for Electrotherm in the solar industry?
The Central and Renewable energy ministry planning for 2 GW per annum solar energy additions in India is a challenging objective and now that market is promising, we expect same pace to continue till 2022. We are well equipped to respond to the market demand in terms of technology and capacity utilisation. We are at present holding a respected market position in terms of quality and market share which we hope to continue and grow in near future.