Ed 3.0-2014 Energy Handling Tests - ArresterWorks
ArresterWorksArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsArresterFacts 033 Rev 3Overview of IEC 60099-4Ed 3.0-2014Energy Handling TestsPrepared byJonathan WoodworthConsulting EngineerArresterWorksArrester Facts 033 Rev 3 Sept 2016Copyright ArresterWorks 2016
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsOverview of the IEC 60099-4 Ed 3.0 2014Energy Handling TestsJonathan Woodworth ArresterWorksTopicsNew DefinitionsNew Arrester Classification SystemNew Operating Duty Test (Thermal Rating)Impulse Energy Ratings (Charge Transfer Rating)Selecting the Right Energy RatingNew Protective Level DefinitionsHow to Calculate ChargeArresterFacts 033 Rev 3As stated in the first edition of this ArresterFacts,more changes were possible since the standardrevision process was not complete. In mid-2014 theEd 3.0 of 60099-4 was published with many newitems included. This edition of Arrester Fact 033covers the Final Energy Handling test changes inthis new standard.IntroductionIt was apparent to stakeholders in surge arresters formany years that the Line Discharge Classificationsystem used to quantify an arrester’s energy mplation by the IEC maintenance team TC37MT4, the following issues clearly needed resolution.1. Previous tests did not provide a standardizedmeans of establishing and verifying energyhandling capability. This left it to manufactures todevelop their own procedures for calculatingproduct energy handling capability, resulting in,energy ratings that varied from one manufacture toanother.2. Users who perform transient studies of theirsystems to determine protective needs requiredata that is more realistic.3. Impulse withstand characteristics and thermalwithstand characteristics were tested (indirectly)using the same tests. However, they were notdiscernible from one another.Copyright ArresterWorks 2016It became clear early on that it would be desirable tomodify the tests to provide means of independentlyverifying arrester thermal withstand capabilities andimpulse withstand capabilities. Previously, the twowere intermingled in both the operating duty tests andthe low-current long-duration (transmission linedischarge) tests.In 2014 the IEC published the 3rd Edition of IEC 600994, the most widely used arrester tests standardworldwide. The maintenance team navigated throughall the needs of the industry and IEC organization atthe same time and the document published on time.Substantive changes were made in the area of arresterenergy handling capabilities and in the means ofclassifying arresters.To address the needed changes in energy testing, twotests were developed that quantify the impulse typesurge durability and thermal withstand capabilityseparately. The issues with arrester classificationhave been resolved by adopting an IEEE system,where arresters are classified as either Station Classor Distribution Class arresters. Each arrester classhas a specific set of tests to pass, which in turn definestheir class. The Line Discharge Classification ofarresters is replaced with this new classificationsystem.As a member of the IEC maintenance TC37 MT4 thatdeveloped these tests, I realize that this change couldbe difficult to understand, so I have written thisArresterFacts to help users have a clearerunderstanding. This document will also address howto apply these new tests to the benefit of all.New and Important DefinitionsDistribution Class Arrester: Arresters intended foruse on distribution systems, typically of Us 52 kV, andare meant to protect components primarily from theeffects of lightning. The arrester classification isassigned based on the test series applied during type
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling Teststests. The distribution class will be subdivided intoHeavy (10kA), Intermediate (5kA) and Light Duty(2.5kA) arresters based on the impulse current (In)used in the Operating Duty Test.or unacceptable electrical degradation to the MO(MOV) resistors.Charge Transfer: A unit of measure that quantifiesthe current flow through the arrester over the time ofthe event. It is calculated as the integral of theabsolute value of the current over the time of the surgeand is measured in coulombs.Station Class Arrester: Arresters intended for usein substations to protect the equipment from lightningand switching surges and are typically but not onlyintended for use on systems of Us 72.5 kV. Theclassification is assigned based on the test seriesapplied during the type test. This class of arrester willbe subdivided into Heavy (20kA), Intermediate (10kA)and Light (5kA) arresters based on the impulse current(In) used in the Operating Duty Test.New Arrester ClassificationsThe classification of an IEC rated arrester will be basedon the data provided in Table 1. If the arrester is testedper the tests in the selected column and passes alllevels, then it may be rated at that level.Thermal Charge Transfer Rating, Qth: Thecharge, given in coulombs (C) that may betransferred through an arrester or arrester section in athermal recovery test without causing a thermalrunaway.This classification scheme replaces the previous LineDischarge (LD) Class. With this new system, there isno possibility that a 10kA Station arrester can beclassified as a 20kA Station Arrester as may havebeen the case in the previous LD system by increasingthe discharge voltage of the arrester. Not only must theenergy dissipation (kJ/kV) be at an acceptable level,but the charge transfer (in coulombs) must also beacceptable in order to classify an arrester at the nextlevel up.Thermal Energy Rating, W th : The energy, given inkJ/kV of Ur, which may be dissipated by an arrester orarrester section in a thermal recovery test withoutcausing a thermal runaway.Repetitive Charge Transfer Rating, Q rs : Thecharge, given in coulombs (C) in the form of a singleevent that can be transferred at least 20 times (at timeintervals that allow for cooling to ambient temperature)through an arrester without causing mechanical failureArrester classStationDistributionDesignation and Duty ominal discharge current20 kA10 kA10 kA10 kA5 kA2,5 kASwitching impulse dischargecurrentQrs (Coulombs)2 kA1 kA0,5 kA------ 2.4 1.6 1.1 0.4 0.2 0.1Wth (kJoules/kV) 10 7 4------------ 1.1Class 4/5Class 3Class 2Class 1 0.7Class 15kA 0.45Class 12.5kAQth (Coulombs)Old ClassificationTable 1: Arrester Classifications and Energy Handling RequirementsCopyright ArresterWorks 2016
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsRepetitive Charge Transfer Rating Qrs:Test ProcedureTest RationaleThe repetitive charge transfer test replaces the longduration current impulse withstand test and is appliedto disks only, not arresters. For station type arresters,a switching surge or half sine surge is applied. Forarresters applied to systems 52kV (distributionarresters) a half sine wave of 200us is used for the test.This test is applied to all non-gapped MOV typearresters. The only difference in the test betweenStation and Distribution Class arresters is thewaveshape of the 20 impulses in the rating test. TheQrs test has been designed to test the capability of anarrester to withstand discharges such as lightning orswitching surges. It is performed on disks only anddoes not need to be a thermal equivalent section. Itwas explicitly the desire of the working group toseparate the thermal energy handling capability andthe impulse energy handling capability. Therefore, tensets of two impulses each are applied in succession.This is believed to be an acceptable number that willnot drive the disk to a temperature that would damagethe materials. There is a cooling period between setsto ensure that this rating is not a one or two shot ratingbut rather that it can sustain this rating for many surgesduring its service life. It is very important also to notethat one failure during these 200 impulses is allowed.If a second failure occurs, another 10 samples can betested with 20 impulses each. This results in a 1/200or 2/400 pass criterion. This new approach allows forconsideration of a verified failure probability (which isnot the case when 3 samples are tested by 18impulses each and no failure is allowed). It is furtherimportant to note that the extrapolation from thevaristor performance to an anticipated arresterperformance is considered because the varistors areRepetitive Charge Transfer Rating Test Sequence Qrs10 groups of two current impulses. Thewaveshape depends on arrester typeResidualVoltage atInResidualVoltage at InUrefUrefTest Procedure DetailsThe test procedure is written for both Station andDistribution Class arresters. The only differencebetween the two is the wave shapes and amplitudes.In preparation for the repeated impulse, the residualvoltage at In and Vref are measured. Both are measuredafter the test as part of the pass/fail evaluation.For the first time in arrester testing, the referencevoltage of the arrester is used as part of the pass/failcriteria. It has been determined during the researchand development of this test that small changes in Vrefare a sign of degradation of the varistor material.Therefore, a greater than a 5% change in Vref isconsidered a sample failure. The residual voltage isalso sensitive to degradation and a greater than 5%change in residual voltage is also considered a samplefailure.The repeated impulse is a switching surge for stationclass arresters and the amplitude is set by themanufacturer at 110% of the desired charge transferrating of the device. For distribution arresters theimpulse is an 8/20 impulse. Transmission linearresters use 200us to peak surge. Each sample isimpulsed 20 times in 10 sets of two impulses 1minute apart per impulses. Ample cooling time isallowed between each impulse set to allow disk toreturn to ambient temperature.Time Current impulses 1 minapart at 1.1xQrs8/20 Impulse at .5kA/cm2 peakcurrent densityFigure 1: Repetitive Charge Transfer Rating Test Sequencetested at a 10% higher charge level than specified(factor 1.1) than the complete arrester.Copyright ArresterWorks 2016At the end of the energy injection test sequence, afterthe disks have returned to ambient temperature,three final tests are applied:1.2.3.Vref,Residual voltage at InOne 8/20 current surge of .5kA/cm2peak current
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsThe equation for calculating chargelooks intimidating, but there are easierways to determine charge using asimplifiedtrapezoidalruleforcalculating a definite integral in aspreadsheet as shown in Annex A ofthis document or mathlab program.At the moment, most transientanalysis programs can readily outputthe energy dissipated by an arrester,but outputting charge requires someextra modelling until the softwarepackages are updated.For the Qrs test and final rating it isexpected that the values will bebetween .5 and 25 coulombs. Therating will be expressed in coulombsand not as a class or level. However, each class ofarrester does have a minimum requirement to meetand is stated in Table 1 above. The rating isdetermined as 90% of the repeated impulse levelduring the 20 shot series.Figure 2: Equations for calculating charge of a surge. [6] Note thisis for absolute value of (i)tThe final impulse is to stress the disk one last time tomake sure that the final Vref or residual voltage impulsedid not create any internal cracks in the material thatcould go undetected.The disk is considered passed if it has not exceededthe 5% change limit of Vref and residual voltage at Inand is not physically damaged. If one sample fails, 10more samples can be tested and evaluated. If morethan one sample fails in the second set the chargerating cannot be claimed and the test must becompleted at a lower charge transfer level.Rating ConsiderationsNew Operating Duty TestTo verify the thermal energy rating Wth(Us 52kV) (Station Class Arresters)To verify thermal charge transfer rating Qth(Us 52kV) (Distribution Class Arresters)Test RationaleThis new operating duty test is designed to quantify theThe Qrs characteristic will be quantified in terms ofenergy dissipation or charge transfer necessary tocharge (coulombs) and not energy dissipation (joules).raise an arresters temperature to a level where it is notChargehasbeenchosen as a test basisOperating Duty Test of IEC 60099-4 Ed 3.0Thermal Energy Rating Wth for Station Arresters orfor the purpose ofThermal Charge Transfer Rating Qth for Distribution Arrestersbettercomparison100kA 4/10 μs1 or more impulsesbetweendifferent2x for Stationwith energy and waveWithin 100ms8/20μs1xforDistribution8/20 μsmakesofMOVshape dependent on apply Ur for 10 secResidualarrester typethen Uc for 30 min Residualarresters.EnergyVoltage at InVoltage at InvaluescanbeUref at IrefPre Heatcalculated from this60 C orHigherinformationbymultiplying the chargeTime withtherelatedswitchingimpulseprotection level.Figure 3: Thermal Rating Test Sequence (New Operating Duty Test)Copyright ArresterWorks 2016
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling Testsstable while at operating conditions. For a high voltagearrester the unit of measure can be joules or coulombs.For arresters used on distribution systems the unit ofmeasure will be coulombs. Again the use of chargetransfer eliminates the potential confusion caused byjoule ratings with respect to residual voltage. It is againthe explicit goal of the developers of this test toseparate the thermal rating from the impulse rating ofthe arrester.Test ProcedureThis test sequence is the new Operating Duty Test.The fourth and final set of energy inputs to the arresterare the ones that will be used to rate the arrester. Priorto the last set of impulses, the arrester must be heatedto 60 C unless the arrester is a UHV arrester. (ForUHV arresters the temperature for this test isdetermined using another test sequence) Per the testprocedure, the energy inputs are as follows:Station Arresters - Arresters on systems of Us 52 kVRated energy injection within three minutes by one ormore long-duration current impulses or by unipolar sinehalf-wave current impulses or, in case of NGLA, bylightning discharge impulsesDistribution Arresters - Arresters on systems of Us 52 kVRated charge transfer within one minute by two lightningcurrent impulses 8/20 μsThe thermal energy/charge transfer rating will beexpressed in joules for station class arresters appliedto systems 52kVand coulombs forTable 2 Comparison of the Old and New Energy Rating Levels for Station Class Arrestersdistribution classOldOldCorrespondingEstimatedCharge calculated with ednew thermalcurrent atsame current and durationnew repetitiverange ofminimumenergy ratingold LD testas for old LDC to give thecharge transfersystem 52kV.Stationtest**required minimum energyratingvoltage ***Wthenergy*ACkVclassarrestersQrskJ/kVkJ/kVCrated below 52kV22,145381,101,1up to 300can be tested and33,377211,781,6up to 420rated in the same45,0109622,752,4upto 525manner as ratings 52kV.56,91411183,753,6up to 800Table 3: Rated Thermal Charge Qth for Distribution ArrestersThe characterization and conditioning portion of thetest may be performed on the disks in still air, howeverthey may be tested in a dielectrically prorated sectionto avoid dielectric testing later. The thermal recoverypart of this test must be performed on thermallyprorated sections. A temperature sensor must beintegrated in the sample such that the temperature ofthe active part can be measured. If not dielectricallyequivalent, then another test is necessary to qualify thedielectrics. (This separate test is not part of thisoverview)The initial Vref and In tests in the sequence are to setthe baseline for evaluation after the thermal stresses.The next two surges are meant to stress the internalcomponents and simulate aging of the disk. Thecurrent amplitude of these two high current impulses isthe same as the two high current impulses in thepresent Operating Duty Test.Copyright ArresterWorks 2016NominalDischargeCurrent (kA)Qth Rating(Coulombs)Qth perimpulse(Coulombs) Corresponding8/20 currentamplitude (kA)2,5,45,23 ( /- 10%)145,7,35 ( /- 10%)22101,1,55 ( /- 10%)34Within 100 ms from the energy or charge application,a voltage equal to the elevated rated voltage Ur shallbe applied for 10 s and thereafter a voltage equal tothe elevated continuous operating voltage Uc shall beapplied for a minimum of 30 minutes to demonstratethermal stability. Resistive component of current orpower dissipation or temperature or any combinationof them shall be monitored until the measured value isappreciably reduced (success), or thermal runawaycondition (failure) is evident.The thermal charge transfer or thermal energy ratingwill equal the sum of the thermal charge transferimpulses for station arresters or thermal energy rating
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling Testsof two impulses for distribution arresters. The samplemust also not experience a change in residual voltageat In of more than 5%.to a prospective switching surge voltage and isdischarged through the arrester at its protective levelduring twice the travel time of the line. (for switchingsurges)Rating SystemThere are minimum rating requirements for Stationand Distribution Class Arresters, however the actualThermal Rating will not be mandated by this test.Station Class arrester will have a Thermal Rating asgiven by the manufacturer and tested per the abovetest. Station Class Arresters will have Thermal EnergyRatings W th from 4 kJ/kV-Ur to 30 kJ/kV- Ur.Distribution Class arrester will only have ThermalCharge Ratings and must meet the minimumrequirements as shown in Table 1.Units of MeasureIf joules are used in the evaluation, the unit of measureis joules/kV-Ur. If charge transfer is used then the unitof measure is coulombs. The method to calculate bothjoules and coulombs is the same as shown in annex Aof this document with the only difference being forjoules, the product of the voltage and current isintegrated over time instead of just the current.Comparison of Old and New ClassificationSystemAnnex K of the new standard shows a detailedcomparison of the old and new classification methods.Table 2 is an example of the potential rating and theequivalent rating from the current system and comesdirectly from the annex. The Old LDC Class 1 is verysimilar to the new Distribution Class Arrester and theOld LDC 2,3,4,5 will become Station Class Arresters.Selecting the Right Station Class ArresterEnergy RatingWith this new energy rating system, the requiredenergy rating of an arrester can be determined by firstcalculating the level of energy the system willdischarge into the arrester and then selecting thearrester with a Thermal Energy Rating W th that isabove the system response. The prospective energythat a system will require of an arrester can bedetermined using transient analysis software, but ifthat is not available a simplified formula is in IEC60099-5. The simplified arrester energy formulae isbased on the assumption that the entire line is chargedCopyright ArresterWorks 2016W is the energy in Joules that will be dissipated bythe arrester for the given surge levelL is the line length;c is the speed of light;Z is the line surge impedances;Ups is the arrester residual voltage at the lower of thetwo switching impulse currents;Urp is the representative maximum switching voltage.For example, if the calculated energy dissipated byan arrester using the above single surge formula is7kJ/kV then the desired single or multiple surgethermal energy rating W th of the arrester should be aminimum of 7kJ/kV.Other Tests that changed in the 60099-4Ed 3.0 - 2014There are several other significant changes that haveoccurred in Ed 3.0 of 60099-4 including:Temporary Overvoltage Test: This is now a requiredtest and not an option as in the past.Steep Front Residual Voltage Test: This test hasnew methods required to reduce the potential ofmisunderstanding the data.Disk Aging Tests: In the past this test was aprocedure that allowed for an increasing watts at theend of the test. As of this new standard, disk agingwith an upward trending watts loss will not be allowed.If the watts increase more than 1.05 times the initialwatts at the end of the test, the disk design cannot becertified. As a result of this change, there is no requiredvoltage adjustment for aging in the thermal evaluationtests.5000 hr Aging Test of Housings: This test is nolonger suggested as an alternative to the 1000 hr test.UHV Arresters: Requirements and tests for UHVarresters (for highest system voltages Us 800 kV)are introduced.
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsProtective Level Definitions ClarifiedIn an effort to keep terms clear, the protection levelshave been expanded and their acronyms clarified.There are no new protection levels, only the termsused to refer to them have been slightly modified.The new designations are summarized in thefollowing definition:3.50 protective characteristics of arrestersa combination of lightning impulse protection level(LIPL), switching impulse protection level (SIPL) andsteep current impulse protection level (STIPL)3.33 lightning impulse protection level, LIPL or Uplthe maximum residual voltage of the arrester for thenominal discharge current.3.66 steep current impulse protection level, STIPLthe maximum residual voltage of the arrester for asteep current impulse of magnitude equal to themagnitude of the nominal discharge current3.68 switching impulse protection level, SIPL orUpsthe maximum residual voltage of the arrester for theswitching impulse discharge current specified for itsclassConclusionsWith the publication of this new standard, the industrynow has a test standard that finally reduces theambiguity of energy rating and energy testing ingeneral.Arresters of different designs can beaccurately compared and fairly evaluated. Specifiersof arrester can request a specific energy rating and allthose submitting quotes will be submitting the sametype of arrester. Users of arresters can now beconfident that they are applying the correct arrester forthe application at hand. Manufacturers can now run atest that is standardized and meaningful to the usersand specifiers.Copyright ArresterWorks 2016About ArresterFactsArresterFacts are copyrighted documents byArresterWorks, but can be duplicated for educationalpurposes as long as credit is properly given. EnjoyJWReferences[1] Hinrichsen, Reinhard, Richter (on behalf of CigréWG A3.17), Energy handling capability of highvoltage metal-oxide surge arresters Part 1: A criticalreview of the standards, Cigré SC A3 TechnicalColloquium, Rio de Janeiro, September 12/13, 2007[2] IEC TC37 MT4 CD 37 381e CD Energy Handlingand UHV Arrester revisions[3] http://en.wikipedia.org/wiki/Trapezoidal rule[4] IEC TC37 MT4 CD 37 400e CD (IEC 600994/Ed3)[5] IEC TC37 MT4 37 398A CC ( MT4 Responsesto first CD 381e)[6] Hinrichsen , Calculating Charge of a Surge, IECTC37 MT4 IWD 2010 26a[7] IEC TC37 CC 37 391 Committee Responses toCD 391
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling TestsAnnex A Calculating Charge using a simpletrapezoidal rule in Excel [3]Copyright ArresterWorks 2016
ArresterFacts 033.3 Overview of IEC 60099-4 Ed 3.0 -2014 Energy Handling Tests Copyright ArresterWorks 2016 Repetitive Charge Transfer Rating QFile Size: 819KB
September: 2013 33,391.18 9/24/2013 October: 2013 33,391.18 10/24/2013 December: 2013 65,031.50 12/20/2013 January: 2014 33,099.37 1/23/2014 February: 2014 33,099.37 2/24/2014 March: 2014 33,099.37 3/24/2014 April: 2014 31,662.23 4/25/2014 May: 2014 31,662.23 5/22/2014 June: 2014 31,662.24 6/26/2014 392,881.03
on work, power and energy]. (iv)Different types of energy (e.g., chemical energy, Mechanical energy, heat energy, electrical energy, nuclear energy, sound energy, light energy). Mechanical energy: potential energy U mgh (derivation included ) gravitational PE, examples; kinetic energy
Forms of energy include radiant energy from the sun, chemical energy from the food you eat, and electrical energy from the outlets in your home. All these forms of energy may be used or stored. Energy that is stored is called potential energy. Energy that is being used for motion is called kinetic energy. All types of energy are measured in joules.
reduces Kinetic Energy and increase Potential Energy A: The energy is stored as potential energy. PE is like your saving account. Potential energy gain (mg h) during the rising part. We can get that energy back as kinetic E if the ball falls back off. During falling, Kinetic Energy will increase mg h. Potential energy will reduce mg h.
Energy is often defined as the ability to do work. Pair up and list as many forms of energy as you can. Electrical. Chemical. Nuclear. Magnetic. Elastic. Sound. Gravitational energy. Kinetic energy (energy of motion). Thermal energy (heat energy). Potential energy. Potential energy
kinetic energy and potential energy as the ball moves. The bars in the figure show that the ball's total energy does not change. The Law of Conservation of Energy The total energy in the universe is the sum of all the different forms of energy everywhere. According to the law of conservation of energy, energy can be transformed from one
changes to thermal energy. Thermal energy causes the lamp's bulb to become warm to the touch. Using Thermal Energy All forms of energy can be changed into thermal energy. Recall that thermal energy is the energy due to the motion of particles that make up an object. People often use thermal energy to provide warmth or cook food. An electric space
32 Renewable Energy 33 References To learn more about DOE programs in energy efficiency and renewable energy, visit the Office of Energy Efficiency and Renewable Energy's web site at www.eere.energy.gov "High energy costs can really pinch American families. While the Department of Energy is working hard to develop new technologies to
