USE INCREASING

Evening Star, Issue 22362, 11 June 1936, Page 6

USE INCREASING

ELECTRICITY IN BRITAIN SUCCESS OF THE GRID When the construction of the national electricity grid was completed in 1933 public interest naturally veered from the engineering side of the project to its commercial aspect, and perhaps the most striking feature of the. eighth annual report of the Central Electricity Board is the credit balance of over £1,021,000 that lias resulted from trading operations during the past year (says a writer in the ‘ Manchester Guardian ’). Since the full economies possible can only be obtained gradually as the load on the public electricity supply system grows, trading operations being based on a long-term and not on an annual budget, this figure can be regarded as very satisfactory. Further, it is estimated that capital expenditure on generating plant to the extent of at least £11,400,000 has been saved as a direct result of the grid’s existence, and in 1935 the cost of generation was reduced by some £920,000 owing to the concentration of production at the more efficient stations. Economies of this order give an added interest to the announcement made last December that a thermal efficiency of over 29 per cent.—a record for the power stations of the world—had been achieved at Battersea. 70 PER CENT. EXPANSION. The influence of tthe national electricity scheme is seen in many other ways. Over the past six years, during which the grid has been building and getting into its stride, the output of electricity in this country has expanded by 70 per cent., whereas the world output has risen by 20 per cent. only. In 1935, when general trading by the Central Electricity Board was in force through the greater part of the country, some 17,565,000,000 units were generated in public supply stations in Great Britain —about 2,100,000,000 more than in 1934—and 95 per cent, of this was generated in nearly 150 stations operating under the direction of the board. To satisfy the increasing demand new generating plant totalling 277,000 kw. in capacity and including a 105,000 kw. set at Battersea (the largest in Europe) has been put into commission, and _ at the end of 1935 the selected stations had an aggregate output of nearly 7,000,000 kw. On the Galloway water power scheme 67,000 kw. of hydroelectric plant is in operation at Tongland and Glenlee, and construction at the smaller stations at Carsfad, Earlstoun, and Kendoon is well under way. The first section of the new steam station at Fulham, comprising two 60,000 kw. turbo-generators, is also approaching completion. During the year arrangements were made to operate Messrs Lever Bros.’ power plant at Port Sunlight in conjunction with the grid, bringing it an additional load of 40,000,000 units a year. In the next few years at least the demand is expected to increase considerably, and for the winter of 1936-37 extensions are in hand l at 22 stations in various parts of the country, covering plant with a total capacity of 350,000 kw, and including a 75,000 kw set for Barking and 50,000 kw sets for Kearsley (Lancashire Electric Power Company) and Hams Hall (Birmingham Corporation). Arrangements have also been made for further extensions aggregating 670,000 kw of generating plant, some of which will be in commercial operation by the winter of 1938-39. The most important of these are at Dalmarnock (two 50,000 kw sets); Fulham (60,000 kw); and Barton, Manchester; Clarence Dock, Liverpool; and, Hams Hall, Birmingham (50,000 kw each). 4,075 MILES OF LINE.

, Hand in hand with the interconnection of power stations has gone the standardisation of frequency of supply throughout the country. This involves the reconstruction or replacement of generating plant, converting plant, and motors, and has meant work not only in the supply companies’ stations, but also on the premises of some 340,000 consumers whose supply had to remain uninterrupted. About'7s per cent, of the standardisation work has been completed. The transmission line network constituting the essence of the grid covered about 4,075 miles at the end of 3935, 2,880 miles operating at 132.000 volts, and the remainder at 66.000 or lower voltages. During the year various extensions were carried out to increase supplies at existing centres of demand and to serve new areas as occasion arose. The secondary ring through Colchester, Clacton-on-Sea, Printon, and Harwich, and the new secondary line from Three Bridges to East Grinstead were finished and brought into service. ■ Preliminary surveys and the acquisition of wayleaves were begun on a new 132,000-volt line from Tronbridge to Stoke-on-Trent; a new 33,000-volt line from Colchester to Coggeshall; and additional lines between Stout-port and Worcester (132.00volt), Carlisle and Egremont (33,000volt), Bourne, Sin-fleet, and Boston (33,000), and Worthing and Littlehampton (33,000-volt). At the opposite ends of England arrangements were made to connect Ramsgate and Berwick-on-Tweed to the grid. Transforming and switching stations were brought into operation at East Grinstead, Lewes, Newton Abbot, Exeter, Oxford, Glossop, Workington, and Glenlee. Rural development in South Scotland was assisted by the provision of a number of tappings on the 33,000volt ring in Berwickshire. At the end of the year there were 280 switching and transforming stations on the grid, with an aggregate transforming capacity of 8.862,700 k.v.a. • LIGHTNING, FOG, AND FUMES. Research has been carried out into various phenomena such as voltage surges (including those due to lightning), the pollution of insulators by fog and dirt in industrial areas, the corrosion of overhead lines by saltladen air on the coast, and gas and fumes from factory chimneys, and the construction of high-voltage circuit breakers. In the last connection work has been facilitated by the installation of elaborate testing equipments for circuitbreakers in the works of the various manufacturers, the latest of which is now in operation at Witton, near Birmingham ; here instantaneous short circuits up to 2,000,000 k.v.a. can be produced at voltages up to , 132,000, enabling one of the worst troubles of electrical power systems to be reproduced for test purposes.