Accuracy and Results of Steam-Consumption Tests on Medium Steam Turbine-Generator Sets

Abstract

Abstract Precision steam-rate or heat-rate tests on turbine-generator sets insure their owners and builders that the sets equal guaranteed and expected performance. The writer’s company made such tests on 22 medium-sized sets rated 2500 to 18,750 kw between 1946 and 1952. Most were tested at its plant at Lynn, Mass., on facilities for loads of 15,000 kw or less, with steam up 1500 psig and 1000 F. This paper presents the test methods and results, emphasizing an analysis of their accuracy. This analysis shows: (a) 0.5 per cent uncertainty in manufacturing and factory-testing these sets; (b) 0.3 per cent as the day-to-day uncertainty of tests; (c) 0.17 per cent uncertainty to be charged to the instrumentation of factory tests; (d) probably 0.5 per cent poorer performance of tests in the owner’s plants than in factory tests. This analysis confirms our belief of many years that it is proper to accept or reject a turbine-generator set on the basis of precision tests, with no allowance for test error.