ASME PTC6.2:2004 pdf download Steam Turbines in Combined Cycles
1-1 0BJECT
This Code provides procedures for the accurate test-ing of steam turbines in combined cycles. It is the intentof this Code that accurate instrumentation and measurement techniques be used to determine performanceIn planning and running the test, the Code User muststrive to follow the procedures in this Code to meet theuncertainty requirements.
1-2 SCOPE
This Code may be used for testing steam turbines incombined cycles with or without supplementary firingand in cogeneration applications. Within these categories of combined and cogeneration cycles, this Codeis applicable to condensing and noncondensing steamturbines, to reheat and nonreheat steam turbines, andto induction/extraction steam turbines. The variety ofcycles presents challenges in writing a code that ad-dresses all issues encountered for all cycle configura-tions. ASME PTC 6 is the appropriate code for testingsteam turbines in nuclear and fossil-fired regenerativefeedwater heater cycles. This Code is applicable only toturbines in cycles in which steam is the working fluid.This Code provides procedures for testing and calcu-lating turbine-generator output performance correctedto reference conditions as a measure of overall turbineperformance.This Code contains rules and proceduresfor the conduct and reporting of steam turbine testingincluding requirements for pretest arrangements, testing techniques, instrumentation, methods of measure.ment, and methods for calculating test results and un-certainty.
1-3 UNCERTAINTY
The underlying philosophy of this Code is to achievetest results of the lowest uncertainty based on currenttechnology and knowledge, taking into account test costand value of the information obtained. To accomplishthis and because of the various configurations coveredby this Code, an upper limit for the uncertainty of eachparameter is established. Exceeding the upper limit ofany parameter’s uncertainty requirement is allowableonly if it is demonstrated that the selection of all in-strumentation will result in an overall test uncertaintyequal to or less than what it would have been had allparametersuncertainty requirements been followed.A pretest uncertainty analysis is required. It serves toestablish the expected level of uncertainty for the test.The test uncertainty shall be calculated in accordancewith the procedures defined herein and by ASME PTC19.1, Test Uncertainty.
A post-test uncertainty analysis is also required. It isused to determine the uncertainty for the actual test.This analysis should confirm the pretest systematic andrandom uncertainty estimates and validate the qualityof the test results.
The maximum uncertainty permitted by the Code willbe influenced by the actual turbine cycle and the sensi-tivity of the corrected results to cycle variables. The com-bination of the applicable test uncertainty limits of eachof the measurands shown in Table 3-6.41 and Section 4will determine the allowable test uncertainty for thatparticular configuration and test. For example, the cal-culated uncertainty for a typical reheat cycle derived using the limiting uncertainties of all components is 0.5%as given in Nonmandatory Appendix B.