IEEE 3-1982 pdf free.IEEE Recommended Practice in the Selection of Reference Ambient Conditions for Test Measurements of Electrical Apparatus.
IEEE 3-1982 test results and the performance ofelectrical apparatus are significantly influencedby variations in such parameters as temperature,barometric pressure，and humidity. A meaningful comparison of the results of two tests madeunder different ambient conditions is possiblewhen the result of one of the tests is correctedor adjusted to indicate the results that wouldhave been obtained if the ambient conditionsfor that test had been identical with those forthe other.
Especially in the situation where several testsperformed under different conditions are to becompared, it is advantageous to select standardreference values for all pertinent parametersand then to correct or adjust the results of eachtest to indicate the results that would havebeen obtained if all tests had been performedunder identical conditions，that is，under thereference ambient conditions.
It is the purpose of this document to identifyand recommended a set of standard referencevalues for certain ambient parameters whichare significant inelectrical testmeasurements.
Even though agreedupon correction factorsmay not be available, the ambient temperature,the barometric pressure, and the relative humidity should always be recorded and reported.In this way retesting will not be necessarywhen agreedupon correction factors becomeavailable.
General.The effects of humidity on electrical apparatus and insulating materials arecomplex. Some phenomena correlate betterwith relative humidity，others with absolutehumidity，and there are some that are influenced，but for which no correlation with eitherabsolute or relative humidity has been demonstrated.The electric breakdown or air in nonhomogeneous electric fields, for example varieswith absolute humidity , and correction factorshave been evaluated and correlated for valuesof absolute humidity for many types of apparatus.On the other hand, the conditioning of insulating materials for test,and the testingof finishes,cements，and adhesives are generally based on values of relative humidity.There-fore it is necessary to recognize these practicalconditions by establishing reference and limitingvalues for bothabsoluteand relativehumidity.absolute humidity. The mass of watervapor in a unit volume of air, usually expressedas g/m3 , or as the partial pressure of the watervapor in air in kPa.
relative humidity. The ratio of the par-tial pressure of water vapor in air at a giventemperature，expressed as a percentage, to thesaturation vapor pressure at that temperature.With adequate accuracy it may also be definedas the ratio of the mass of water vapor actuallypresent in a specified volume of air at a giventemperature to the mass that would saturateit at that temperature.
standard reference humidity. A suitablyselected value for which performance data aregiven in records and standards and to which re-sults of tests made at different humidities arecorrected for purposes of comparison andstandardization.
range of testing humidity. The zone ofhumidity conditions considered suitable foracceptance and check tests.IEEE 3-1982 pdf download.