Testing of Boilers and Turbo-Alternators in Power Stations of the Central Electricity Authority

Abstract

The paper refers to the seven years' period following the nationlaization of electricity supply. The various reasons for plant testing are stated but such work is never an end in itself. The average heat rates for 33 sets each of 30 MW. and 30 sets each of 60 MW. are stated, together with their standard deviations. Heat rates as low as 7,800 B.Th.U. per kW.-hr. may be achieved in the foreseeable future. In the seven-year period 77 per cent of new sets were tested, which yields a fair cross-section of the performance of the installed plant. It is the intention to introduce a system of routine testing for the more important machines. In dealing with the subject of boiler tests, available methods are reviewed and consideration is given to recent simplifications of the deferred efficiency test as agreed with the Watertube Boilermakers' Association (W.T.B.A.). A table of average boiler losses for stoker and for pulverized-fuel firing is presented and from this reliable estimates of boiler performance can be deduced so as to allow for several variables which could affect the answer. Water flow enters into the testing of both boilers and turbines. The paper refers to standardization of flow metering in the Central Electricity Authority (C.E.A.) and states that five hydraulic calibrating laboratories are being constructed. The Authority is constantly investigating improved means of flow measurement and hopes thereby to contribute to an improvement in technique. With regard to electrical metering, and in view of the proposal to introduce routine turbine testing, meters should be of the highest quality. N.P.L. certificates have been obtained for a super grade of instrument and results are set out in tabular form. The paper ends by a foreshadow of some possible improvements in electrical integrators.