A56-The World’s Largest Transformer -1930

The above was the title of an article in a UK Journal (IEE Journal Vol 71) in November,1933. It was about two 100 MVA 12.5/33 kV Transformers for Barking B Power Station in UK, made by M/s Hackbridge, a UK transformer manufacturer.?

These 125,000 HP water cooled transformers (those days transformer rating used to be occasionally referred in terms of HP instead of kVA) had a nominal rated output of 93.75 MVA as per British Standard rating, but were capable of a continuous output of 103.125 MVA with an ambient air temperature of 30 degree C at a cooling water of 15?degree C. The efficiency on full load and at 75 degree C was 99.47 % (Total loss 550 kW). Two separately mounted 60 % water coolers (Oil flow 275 gallons per minute and water 180 gallons/minute- 1045 & 684 lpm) provided the necessary cooling. Core type construction used a five-limbed core (core weight 75 tons) with directly wound spiral winding (Helical winding) for both HV &LV windings. Total weight with oil, coolers and accessories was 165 tons with overall dimensions of 23x8.5x20 feet (7.0 x2.6x 6.1 metres). M/s W.B. Dick & Company supplied the transformer oil.

Transport of the transformer from the Hackbridge factory (at Hersham, Walton-on-Thames, Surrey, 24 kms south of London) to Barking power station was by road, using a specially built lorry, the largest in the world, till then. Overall length of trailer was 65 feet (19.8 metres) with steering from both front and rear. A cabin was provided behind the rear bogey for the ‘guard’ who was operating the rear bogey steering and was in continuous telephonic communication with the driver. The average speed of movement over road was very slow, three miles an hour. In view of extremely heavy weight, bridges were avoided. Hence the transformer was taken to Surrey docks, conveyed across the river in a barge and then lifted on to the lorry again for the reminder of the journey to the power station.

This transformer company was claiming their transformer as a record rating in later years too. I doubt the authenticity of it.?I find by 1931, GE (USA) had made a 100 MVA 24/12 kV 50Hz Auto Transformer (percentage impedance 5.5 %; efficiency 99.67 %; Toal weight 87 tons) and AEG (Berlin) made a three winding unit 100 MVA 220/110/33?kV 50 Hz, (Impedance 12.5 %; OFW cooled; efficiency 99.2 % ; Losses 200/600 kW- two winding basis; Internal 125 Tons; Total 219 Tons; oil 45 tons; Transport 168 Tons ,size-29x9x23 feet)?( Source: R. M. Charley, Recent Progress in Large Transformers, IEE Journal, Vol69, No.418, Pages 1189- 1207, October 1931) Against 99.2 % efficiency and 200/600 kW losses, typical losses of a similar 100 MVA 220 kV?Transformer today ( after 90 years) is?99.72 % efficiency and losses 43/245 kW ie losses have come down by 80 % & 60 % respectively!

Any way, it is clear that in early 1930s, 100 MVA 220 kV was the largest rated transformer in the world against today’s 4500MVA 1100kV auto-transformer bank in China and 1800 MVA GSU bank in Europe.

Hackbridge Electric Construction company was established in Hackbridge, Surrey in UK in 1919 for manufacturing transformers. Transformer production was shifted to Hershem, Walton-on-Thames, Surrey in 1923. Distribution transformer production was shifted to ?Isle of Thanet in UK. 1n 1929, company started production of 66 kV class transformers for Central Electricity Board, UK. In 1946, Hackbridge Electric Construction company merged with Hewittic Electric Company and the company name changed to Hackbridge and Hewittic Electric Company. Mercury arc rectifier was the speciality of Hewittic and they were the market ?leaders in that product line. In 1947, HHEC ?incorporated as a public company. A large 100-ton bay was built for the assembly, processing and testing of large 132, 220 and 440 kV transformers, including very substantial test plant with a 3300 kV impulse generator.

A brilliant Indian engineer K. Easwaran from Madras was an apprentice with Hackbridge in late 1940s, soon after his higher studies in London. He was able to impress on Hackbridge management for commencing transformer production in India to overcome the restrictive import rules of the Indian Government. In 1956, he established a factory in Madras (Chennai) in India to manufacture power and distribution transformers, in technical and financial collaboartion with Hackbridge and Hewittic Electric Company. A company was formed in India with the name of Hackbridge-Hewittic and Easun Ltd (HHE). I visited their transformer factory in Chennai in 1965 on a study tour from my college. This was the first time I visited a transformer factory in my life, never knowing then that next half a century, I will be running around transformers, rolling out of factory floors.

HHE, India had great reputation for quality and reliability of transformers. They were the first in India to make 132 kV class transformers in 1960s ??and 150 MVA 220 kV Class auto-transformers in 1970s. They could not meet the cut throat competition in the market and hence went out of circuit by the first decade of this century. Certain back fired export jobs added to their misery.

In 1965, the Hackbridge and Hewittic, UK ?merged with English Electric company. In 1971, Hersham transformer factory was closed and the transformer production shifted to Stafford. The Hersham factory buildings were demolished in 1978.?In later years, General Electric Company of UK (GEC) acquired The English Electric company. Later Alsthom acquired GEC and now the company is owned by GE, USA.

https://www.hackbridgeandhewittic.co.uk/training/index.htm?-Booklet given to engineer trainees of HHEC,UK in 1960s

https://www.hackbridgeandhewittic.co.uk/lincoln/index.htm?- History of Hackbridge &Hewittic Ltd