ASME 19.6:2018 pdf free download – Electrical Power Measurements
The methods given herein include direct and indirect determinations ofactive power (watts), reactive power (vars), and power factor produced or consumed in alternating-currentsingle-phase and polyphase electrical circuits, electrical generators, power transformers, and motors. This Supplement does not include such measurements of fundamental electricalpropertiesas voltage,current,frequency,resistance,andimpedance, exceptas neededto supporttheobjectives of this Supplement.
This Supplement emphasizes the methods and instrumentation required to obtain measurement results with the lowest practical uncertainty based on current engineering knowledge, taking into account measurement costs and the value of information obtained from the measurement. Test uncertainty is principally influenced by the quality and calibration of the instruments, experience and judgment of the test personnel, and stability and characteristics of the power system. When estimating the systematic uncertainty of a power measurement, an uncertainty analysis shallbeconductedto identifythepotentialsources ofuncertainty, howthese wereestimated, andalistofall assumptions made that support the estimates presented. Table 1-3-1 presents the requirements for the active power measurement uncertainty for three classes ofmeasure- ments designated as Class A, B, or C. Forthe Class Ameasurements (high quality, minimum uncertainty), the uncertainty can be restricted to a narrow band. For the Classes B and C, a range of uncertainties can occur depending on the in- strumentationselectedand the otherfactors mentioned above. Class B has two options, dependingonthe calibrationand burden data available. Other options may be applicable for exceptions to best practices, provided the uncertainty re- quirements are met for Class B.
For cases ofmonitoring or comparative testing, where the same instruments are used for both initial and later tests, absolutemeasurementisnotthegoalofthetest. Inthesecases,therelativeuncertaintyistheuncertaintyofthedifference between the previous reading and the current one or between the before and after tests of an equipment rebuild or modification. Inthesecases, PerformanceTestCodes thatreferencethis Supplementmayallowtheuseofameasurement that does not meet the requirements of Class A, B, or C, if it is demonstrated that the systematic uncertainties are correlated and essentially cancel out, thus resulting in a low measurement uncertainty. The sections ofthis Supplementdescribe various combinations ofinstruments available foruse in the measurementof electricalpowerandtheircalibrationandapplication requirements. Thespecifictestuncertaintyforeach combinationof instruments can be determined by the procedures outlined in Section 7.
The applicable provisions ofASME PTC 1 are a mandatorypartofthis Supplement. Itshould be reviewed and followed when preparing the procedure for electrical power measurements. ASME PTC 2 defines many of the terms and numerical constants used in this Supplement. The ASME PTC 19 series, Supplements on Instruments and Apparatus, should be consulted when selecting the instruments used to measure the required test parameters and when calculating test uncertainties.
ThisSupplementreliesonmanyreferencesfortestproceduresanddata,suchasASME,IEEE,etc.Thepartiesshallagree touseotherrecognizedinternationalsourcesfortheseproceduresanddata,includingapplicablerevisions.Thefollowing publications form a part ofthis Supplement to the extent specified herein. Unless otherwise indicated, the latest edition shall apply.
ASME PTC 1, General Instructions
ASME PTC 2, Definitions and Values
ASME PTC 19.1, Test Uncertainty
Publisher: The American Society of Mechanical Engineers (ASME), Two Park Avenue, New York, NY 10016-5990 (www.asme.org)
IEEE 120-1989, IEEE Master Test Guide for Electrical Measurements in Power Circuits
IEEE C12.1, Code for Electricity Metering
IEEE C57.12.90, Standard Test Code for Liquid-Immersed Distribution, Power, and Regulating Transformers
IEEE C57.13-2016, Requirements for Instrument Transformers
Publisher: Institute of Electrical and Electronics Engineers, Inc. (IEEE), 445 Hoes Lane, Piscataway, NJ 08854 (www.ieee.org)