IEEE Jackson PES Meeting.pptx

IEEE Jackson PES Meeting

IEEE Jackson PES MeetingRoutine and Design tests on power transformers as required by IEEE C57.12.00 and C57.12.90C57.12.00 IEEE Standard for General Requirements for Liquid-Immersed Distribution, Power and Regulating TransformersService ConditionsRating DataConstructionShort CircuitTesting and CalculationsTolerancesConnections for shipmentAnnex for Front of Wave (Informative)C57.12.90 IEEE Standard Test Code for Liquid-Immersed Distribution, Power and Regulating TransformersResistance MeasurementsPolarity and Phase relation Ratio testsNo-load loss and excitationLoad Loss and impedanceDi-electric testsTemperature rise testsShort circuit testsAudible sound levelCalculated DataAnnex A Partial DischargeAnnex B Frequency conversionRoutine and Design testsRoutine tests shall be made on every transformer to verify that the product meets the design specifications.Design tests shall be made on a transformer of new design to determine the adequacy of the design of a particular type, style or model of transformer or its component parts.Other tests are identified in individual product standards and may be specified by the purchaser in addition to routine tests.Insulation levelsClass I power transformers shall include power transformers with high-voltage windings of 69kV and below.

Class II power transformers shall include power transformers with high-voltage windings from 115kV thru 765kV.Routine, design and other tests for transformersTestsTypeExplanation of the testResistance measurements of all windings on the rated voltage tap and at the tap extremesRoutineTo verify that the measured winding resistance is within 3% of the calculated winding resistance, and that all internal connections and welds were performed properlyWinding Insulation ResistanceRoutine for Class-II , Other for Class-ITo measure the quality and dryness of the transformer insulation systemCore Insulation Resistance Routine for Class-II , Other for Class-ITo verify that no unintentional grounds are present on the transformer coreRatio, polarity and phase relation tests on the rated voltage connection and on all tap connectionsRoutineTo verify that all windings have the correct number of turns and all winding leads are properly connected and the correct phase rotation is achieved.Insulation Power Factor and capacitanceRoutine for Class-II , Other for Class-ITo verify the quality of the transformer insulation system. Control (auxiliary) cooling losses OtherTo measure the losses drawn by the fans and other auxiliary devices during operationLow frequency test on auxiliary devices and current transformersOther for Class I, Routine for Class IITo verify the dielectric integrity of the auxiliary devices, wiring and CTsSingle Phase Excitation tests on the rated voltage connection.OtherTo verify that the core design and its performance is satisfactory, and that no failures are located in the winding insulation systemRoutine, design and other tests for transformersTestsTypeExplanation of the testNo-Load Losses and exciting current at 100% and 110% of rated voltage and at rated power frequency and on the rated voltage tap connectionsRoutine To verify that the core was designed and manufactured to meet the calculated/guaranteed core loss valueImpedance voltage and load loss at rated current and rated frequency on the rated voltage connection and at the tap extremes.RoutineTo verify that the windings and active part were designed and manufactured to meet the calculated/guaranteed load loss and percent impedance valuesZero Phase Sequence impedance voltageDesign for Class I, Routine for Class IITo verify that the active parts with windings were designed and manufactured to the calculated/guaranteed zero phase sequence impedance valueTemperature Rise Test -At minimum and maximum ratings of the first unit of a new design - At minimum and maximum ratings when temperature rise tests are specified. - Special ratings per customer specsDesign

Other-Other

Other-OtherThe Temperature Rise Test verifies that the thermal performance of the transformer cooling system is designed and manufactured to meet the calculated and guaranteed valuesLow frequency di-electric test(Applied Potential test)RoutineTo verify that the insulation between the windings and the windings to ground is adequate, including lead clearancesRoutine, design and other tests for transformersTestsTypeExplanation of the testLighting Impulse TestDesign& Other for Class I, Routine for Class IITo verify the insulation class to withstand the guaranteed basic insulation level (BIL)Switching impulse, phase-to-groundOther for both but Routine for 345kV and aboveTo verify the insulation integrity of the transformer for switching stress in the field.Partial Discharge and Radio Interference testRoutine for Class-IIOther for Class-ITo verify the integrity of the transformer insulation system to meet the guaranteed level of apparent charges occur within the transformer.Audible Sound Level TestDesign for first unit and otherTo verify that the sound generated by the transformer does not exceed the guaranteed maximum decibel level during operation.Dissolved gases in oil analysisRoutine for Class-II Other for Class-ITo verify that the transformer had no combustible gas generation during various types of testsCT Ratio and PolarityRoutineTo verify that all current transformers are connected and polarity is correctCT Insulation ResistanceRoutineTo verify that all the secondary leads of the current transformers have adequate insulation to ground all the way to the control cabinet Operational test of all devicesRoutineTo verify all the control wiring is correct and the auxiliary devices are operational.Single phase impedance testOtherTo measure the impedance value of each set of windings separatelySweep Frequency response Analysis testOtherTo measure the response of each phase under different frequencies. This test is to verify any coil movement between different times of testing.