SIST EN 61881:2001
(Main)Railway applications - Rolling stock equipment - Capacitors for power electronics
Railway applications - Rolling stock equipment - Capacitors for power electronics
Specifies capacitors used below an operating frequency of 2500 Hz with a rated voltage limited to 10000 V. Distinguishes beween a.c. and d.c. capacitors
Bahnanwendungen - Betriebsmittel auf Bahnfahrzeugen - Kondensatoren für Leistungselektronik
Applications ferroviaires - Matériel roulant - Condensateurs pour électronique de puissance
Spécifie les condensateurs utilisés au dessus d'une fréquence de fonctionnement de 2500 Hz avec une tension assignée limitée à 10000 V. Distinction est faite entre les condensateurs pour courant alternatif et ceux pour courant continu.
Železniške naprave – Oprema voznih sredstev – Kondenzatorji za močnostno elektroniko (IEC 61881:1999)
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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.þQRVWQRBahnanwendungen - Betriebsmittel auf Bahnfahrzeugen - Kondensatoren für LeistungselektronikApplications ferroviaires - Matériel roulant - Condensateurs pour électronique de puissanceRailway applications - Rolling stock equipment - Capacitors for power electronics45.040Materiali in deli za železniško tehnikoMaterials and components for railway engineering31.060.70Power capacitorsICS:Ta slovenski standard je istoveten z:EN 61881:1999SIST EN 61881:2001en01-februar-2001SIST EN 61881:2001SLOVENSKI
STANDARD
NORMEINTERNATIONALECEIIECINTERNATIONALSTANDARD61881Première éditionFirst edition1999-09Applications ferroviaires – Matériel roulant –Condensateurs pour électronique de puissanceRailway applications – Rolling stock equipment –Capacitors for power electronics Commission Electrotechnique Internationale International Electrotechnical CommissionPour prix, voir catalogue en vigueurFor price, see current catalogue IEC 1999
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61881 © IEC:1999– 3 –CONTENTSPageFOREWORD.7Clause1General.91.1Scope and object.91.2Normative references.111.3Definitions.111.4Service conditions.192Quality requirements and tests.232.1Test requirements.232.2Classification of tests.232.3Capacitance and tan d measurements (routine test).252.4Capacitor loss tangent (tan d) measurement (type test).272.5Voltage test between terminals.272.6AC voltage test between terminals and case.292.7Test of internal discharge device.312.8Sealing test.312.9Surge discharge test.312.10Thermal stability test.332.11Self-healing test.352.12Resonance frequency measurement.352.13Environmental testing.352.14Mechanical testing.372.15Endurance test.392.16Destruction test.432.17Disconnecting test on fuses.512.18Partial discharge measurements (optional type tests).573Overloads.573.1Maximum permissible voltage.574Safety requirements.574.1Discharge device.574.2Case connections.594.3Protection of the environment.594.4Other safety requirements.595Markings.595.1Marking of the units.59
61881 © IEC:1999– 5 –ClausePage6Guide to installation and operation.616.1General.616.2Choice of rated voltage.636.3Operating temperature.636.4Special service conditions.656.5Overvoltages.656.6Overload currents.656.7Switching and protective devices.656.8Choice of creepage distance and clearance.676.9Connections.676.10Parallel connections of capacitors.676.11Series connections of capacitors.676.12Magnetic losses and eddy currents.696.13Guide for fuse and disconnector protection.69Annex A (informative)Waveforms.71Annex B (normative)Operational limits of capacitors with sinusoidal voltagesas a function of frequency and at maximum temperature (qmax).77Annex C (normative)Resonance frequency measuring methods – Examples.81Annex D (informative)Bibliography.85Figure 1 – Destruction test arrangement.45Figure 2 – N source d.c. plus a.c.49Figure 3 – N source d.c.51Figure A.1 – Example of current pulse width.75Figure B.1 – Supply conditions.77Figure C.1 – Measuring circuit.81Figure C.2 – Relation between the voltage across the capacitor and the supply frequency.81Figure C.3 – Discharge current wave shape.83Table 1 – Maximum temperature of cooling medium for unlimited time.21Table 2 – Test voltage between terminals.27Table 3 – Damp heat test.37Table 4 – Testing the robustness of terminals.37Table 5 – Example of current-carrying capacities of screw terminals and bolts.39Table 6 – Endurance test.41Table 7 – Maximum permissible voltage.57
61881 © IEC:1999– 7 –INTERNATIONAL ELECTROTECHNICAL COMMISSION___________RAILWAY APPLICATIONS –ROLLING STOCK EQUIPMENT –CAPACITORS FOR POWER ELECTRONICSFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprisingall national electrotechnical committees (IEC National Committees). The object of the IEC is to promoteinternational co-operation on all questions concerning standardization in the electrical and electronic fields. Tothis end and in addition to other activities, the IEC publishes International Standards. Their preparation isentrusted to technical committees; any IEC National Committee interested in the subject dealt with mayparticipate in this preparatory work. International, governmental and non-governmental organizations liaisingwith the IEC also participate in this preparation. The IEC collaborates closely with the International Organizationfor Standardization (ISO) in accordance with conditions determined on agreement between the twoorganizations.2)The formal decisions or agreements of the IEC on technical matters express, as nearly as possible, aninternational consensus of opinion on the relevant subjects since each technical committee has representationfrom all interested National Committees.3)The documents produced have the form of recommendations for international use and are published in the formof standards, technical specifications, technical reports or guides and they are accepted by the NationalCommittees in that sense.4)
In order to promote international unification, IEC National Committees undertake to apply IEC InternationalStandards transparently to the maximum extent possible in their national and regional standards. Anydivergence between the IEC Standard and the corresponding national or regional standard shall be clearlyindicated in the latter.5)
The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for anyequipment declared to be in conformity with one of its standards.6)
Attention is drawn to the possibility that some of the elements of this International Standard may be the subjectof patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.International Standard IEC 61881 has been prepared by IEC technical committee 9: Electricrailway equipment.The text of this standard is based on the following documents:FDISReport on voting9/522/FDIS9/530/RVDFull information on the voting for the approval of this standard can be found in the report onvoting indicated in the above table.This publication has been drafted in accordance with the ISO/IEC Directives, Part 3.Annexes A and D are for information only.Annexes B and C form an integral part of this standard.The committee has decided that this publication remains valid until 2004. At this date, inaccordance with the committee's decision, the publication will be·reconfirmed;·withdrawn;·replaced by a revised edition; or·amended.
61881 © IEC:1999– 9 –RAILWAY APPLICATIONS –ROLLING STOCK EQUIPMENT –CAPACITORS FOR POWER ELECTRONICS1 General1.1 Scope and objectThis International Standard applies to capacitors for power electronics intended to be used onrolling stock.The rated voltage of capacitors covered by this part is limited to 10 000 V.The operating frequency of the systems in which these capacitors are used is usually below2 500 Hz, while the pulse frequencies may go up to several thousand hertz, in some casesbeyond 10 000 Hz.It distinguishes between a.c. and d.c. capacitors.They are considered as components mounted in enclosures.NOTE – This standard covers an extremely wide range of capacitor technologies for numerous applications:overvoltage protection, d.c. and a.c. filtering, switching circuits, d.c. energy storage, auxiliary inverters, etc.The following are excluded from this standard:–capacitors for induction heat-generating plants operating at frequencies between 40 Hz and24 000 Hz (see IEC 60110);–capacitors for motor applications and the like (see IEC 60252);–capacitors to be used in circuits for blocking one or more harmonics in power supplynetworks;–small a.c. capacitors as used for fluorescent and discharge lamps (see IEC 61048 andIEC 61049);–capacitors for suppression of radio interference (see IEC 60384-14);–shunt capacitors for a.c. power systems having a rated voltage above 1 000 V (seeIEC 60871-1 and IEC 60871-2);–shunt power capacitors of the self-healing type for a.c. systems having a rated voltage up toand including 1 000 V (see IEC 60831-1 and IEC 60831-2);–shunt power capacitor of the non self-healing type for a.c. systems having a rated voltageup to and including 1 000 V (see IEC 60931-1 and IEC 60931-2);–electronic capacitors not used in power circuits (see IEC 60080 and IEC 60166);–series capacitors for power systems (see IEC 60143);–coupling capacitors and capacitors dividers (see IEC 60358);–capacitors for applications requiring energy storage/high current discharge such asphotocopies and lasers;–capacitors for microwave ovens.Examples are given in clause 6.
61881 © IEC:1999– 11 –1.2 Normative referencesThe following normative documents contain provisions which, through reference in this text,constitute provisions of this International Standard. For dated references, subsequentamendments to, or revisions of, any of these publications do not apply. However, parties toagreements based on this International Standard are encouraged to investigate the possibilityof applying the most recent editions of the normative documents indicated below. For undatedreferences, the latest edition of the normative document referred to applies. Members of IECand ISO maintain registers of currently valid International Standards.IEC 60068-2-3, Environmental testing – Part 2: Tests. Test Ca: Damp heat, steady stateIEC 60068-2-14, Environmental testing – Part 2: Tests. Test N: Change of temperatureIEC 60068-2-20, Environmental testing – Part 2: Tests. Test T: SolderingIEC 60068-2-21, Environmental testing – Part 2: Tests. Test U: Robustness of terminations andintegral mounting devicesIEC 60077-1, Railway applications – Electrotechnical components – Part 1: General serviceconditions 1)IEC 60269-1, Low-voltage fuses – Part 1: General requirementsIEC 60721-3-5, Classification of environmental conditions – Part 3: Classification of groups ofenvironmental parameters and their severities – Ground vehicle installationsIEC 61373, Railway applications – Rolling stock equipment – Shock and vibration tests1.3 DefinitionsFor the purpose of this International Standard, the following definitions apply.1.3.1capacitor element (or element)indivisible part of a capacitor consisting of two electrodes separated by a dielectric1.3.2capacitor unit (or unit)assembly of one or more capacitor elements in the same container with terminals brought out1.3.3capacitor bankassembly of two or more capacitor units, electrically connected to each other1.3.4capacitorgeneral term used when it is not necessary to state whether reference is made to an element, aunit or a capacitor bank___________1) To be published.
61881 © IEC:1999– 13 –1.3.5capacitor equipmentassembly of capacitor units and their accessories intended for connection to a network1.3.6capacitor for power electronicspower capacitor intended to be used in power electronic equipment and capable of operatingcontinuously under sinusoidal and non sinusoidal current and voltage1.3.7metal-foil capacitor (non self-healing)capacitor in which the electrodes usually consist of metal foils separated by a dielectric, in theevent of a breakdown of the dielectric; the capacitor does not restore itself1.3.8self-healing metallized dielectric capacitorcapacitor, the electrodes of which are metallized (usually by evaporation); in the event ofdielectric breakdown, the capacitor restores itself1.3.9a.c. capacitorcapacitor essentially designed for operation with alternating voltageNOTE – AC capacitors may be used with d.c. voltage up to the rated voltage only when authorized by the capacitormanufacturer.1.3.10d.c. capacitorcapacitor essentially designed for operation with direct voltageNOTE – DC capacitors may be used with a specified a.c. voltage only where authorized by the capacitormanufacturer.1.3.11model capacitorsmaller unit which simulates a complete unit or element in an electrical test, without reducingthe severity of the electrical, thermal or mechanical conditionsNOTE – The combined sum of stresses should always be considered, for instance the sum of temperature,mechanical conditions and electrical stresses.1.3.12internal (element) fusedevice incorporated in the capacitor which disconnects an element or a group of elements inthe event of breakdown1.3.13overpressure devices1.3.13.1overpressure disconnectordisconnecting device inside a capacitor, designed to interrupt the current path in case ofcapacitor failure
61881 © IEC:1999– 15 –1.3.13.2overpressure detectordevice designed to detect abnormal increase of the internal pressure by an electricalswitch/signal and indirectly interrupt the current path1.3.14internal discharge devicedevice incorporated in the capacitor connected between the terminals of the unit, capable ofreducing the residual voltage effectively to zero after the capacitor has been disconnected fromthe supply1.3.15rated a.c. voltage (UN)maximum operating peak recurrent voltage of either polarity of a reversing type waveform forwhich the capacitor has been designedNOTE 1 – The waveform can have many shapes. Examples are given in annex A.NOTE 2 – The mean value of the waveform may be positive or negative.NOTE 3 – It is important to note that the rated a.c. voltage is not an r.m.s. value.NOTE 4 – Definitions used in this standard can be different from those of IEC 60077-1.1.3.16rated d.c. voltage (UNDC)maximum operating peak voltage of either polarity but of a non-reversing type waveform, forwhich the capacitor has been designed, for continuous operationDamping capacitors, for gate turn-off thyristor (GTO) can be regarded as d.c. capacitors with aripple voltage equal to the rated d.c. voltage UNDC = Ur.In the case of reversal voltage, the use should be agreed between purchaser andmanufacturer.NOTE – If the reversal voltage is small (less than 10 %), the voltage waveform can be considered to be notreversing. For test purposes, UNDC and Ur should be increased by U, the reversal voltage.1.3.17ripple voltage (Ur)peak-to-peak alternating component of the unidirectional voltage1.3.18non-recurrent surge voltage (Us)peak voltage induced by a switching or any other disturbance of the system which is allowed fora limited number of times and for durations shorter than the basic period1.3.19insulation voltage (Ui)r.m.s. value of the sine wave voltage designed for the insulation between terminals ofcapacitors to case or earth. If not specified, the r.m.s. value of the insulating voltage is equi-valent to the rated voltage divided by 21.3.20maximum peak current (Î)maximum peak current that can occur during continuous operation
61881 © IEC:1999– 17 –1.3.21maximum current (Imax)maximum r.m.s. current for continuous operation1.3.22maximum surge current (Is)admissible peak current induced by switching or any other disturbance of the system which isallowed for a limited number of times1.3.23pulse frequency (fp)repetition rate of periodic current pulses1.3.24current pulse width (tt)time of current flow during charging or discharging from one voltage value to another, of thecapacitorNOTE – Pulse current waveform examples are shown in annex A.1.3.25resonance frequency (fr)lowest frequency at which the impedance of the capacitor becomes minimum1.3.26duty cycle1.3.26.1continuous dutyoperation time such that a capacitor is at thermal equilibrium for most of the time1.3.26.2Intermittent dutydiscontinuous working or operation with variable loads which should be described in terms ofON/OFF or HIGH/LOW periods with their durations1.3.27operating temperaturetemperature of the hottest point on the case of the capacitor when in thermal equilibrium1.3.28lowest operating temperature (qqmin)lowest temperature at which the capacitor may be energized1.3.29container temperature rise (Dqqcase)difference between the temperature of the hottest point of the container and the temperature ofthe cooling air1.3.30cooling-air temperature (qqamb)temperature of the cooling air measured at the hottest position of the capacitor, under steady-state conditions, midway between two unitsIf only one unit is involved, it is the temperature measured at a point approximately 0,1 m awayfrom the capacitor container and at two-thirds of the height from its base.
61881 © IEC:1999– 19 –1.3.31maximum operating temperature (qqmax)highest temperature of the case at which the capacitor may be operated1.3.32steady-state conditionsthermal equilibrium attained by the capacitor at constant output and at constant cooling-airtemperature1.3.33capacitor lossesactive power consumed by a capacitorNOTE – Unless otherwise stated, the capacitor losses are understood to include losses in fuses and dischargeresistors forming an integral part of the capacitor.At high frequency, the capacitor losses are predominantly due to losses in connections, contacts and electrodes.1.3.34tangent of the loss angle (tan dd) of a capacitorratio between the equivalent series resistance and the capacitive reactance of a capacitor at aspecified sinusoidal alternating voltage and frequency1.3.35equivalent series resistance of a capacitoreffective resistance which, if connected in series with an ideal capacitor of capacitance valueequal to that of the capacitor in question, would have a power loss equal to active powerdissipated in that capacitor under specified operating conditions1.3.36maximum power loss (Pmax)maximum power loss with which the capacitor may be loaded at the maximum casetemperature1.3.37maximum frequency for maximum power loss and maximum current (f2)frequency at which the maximum current (Imax) produces the maximum power loss (Pmax) inthe capacitor1.4 Service conditionsNOTE – See IEC 60077-1.1.4.1 Normal service conditionsThis standard gives requirements for capacitors intended for use in the following conditions:1.4.1.1 AltitudeNot exceeding 1 200 m.NOTE – The effect of altitude on convection cooling and external insulation should be taken into consideration, ifthe altitude exceeds 1 200 m.1.4.1.2 TemperatureThe climatic ambient temperatures are derived from IEC 60721-3-5 class 5k2 which has arange from –25 °C to +40 °C.
61881 © IEC:1999– 21 –Where ambient temperature lies outside this range, it shall be agreed between the user and themanufacturer.The upper limit of case temperature qmax at which the capacitor may be operated, shall bechosen among the values 55 °C, 70 °C and 85 °C.1.4.1.3 Operating temperature with forced ventilationIf capacitors are intended for forced cooling with a fluid medium, the operating temperatureconditions specified in 1.4.1.2 shall be observed.The following table 1 of preferred temperatures of cooling fluid shall be applied.Table 1 – Maximum temperature of cooling medium for unlimited timeInlet temperature°COutlet temperature°C354045505560The lowest inlet temperature for the cooling fluid may be –25 °C.There are two methods of specifying the upper temperature limit of the cooling medium usingeither the inlet temperature or the outlet temperature.Unless otherwise agreed, the choice of method shall be left to the capacitor manufacturer.For the inlet method, the flow of cooling medium shall be specified.1.4.2 Unusual service conditionsThis standard does not apply to capacitors, whose service conditions are such as to be ingeneral incompatible with its requirements, unless otherwise agreed between the manufacturerand the purchaser.Unusual service conditions require additional measurements, which ensure that the conditionsof this standard are complied with even under these unusual service conditions.
61881 © IEC:1999– 23 –2 Quality requirements and tests2.1 Test requirements2.1.1 GeneralThis subclause gives the test requirements for capacitor units.2.1.2 Test conditionsUnless otherwise specified for a particular test or measurement, the temperature of thecapacitor dielectric shall be in the +5 °C to +35 °C range.If corrections are necessary, the reference temperature shall be +20 °C, unless otherwiseagreed between the manufacturer and the purchaser.NOTE – It may be assumed that the dielectric temperature is the same as the ambient temperature, provided thatthe capacitor has been left in an unenergized state, in a constant ambient temperature, for an adequate period oftime in order to reach thermal equilibrium.The a.c. tests and measurements shall be carried out with a sinusoidal voltage of 50 Hz or60 Hz, unless otherwise specified.2.2 Classification of testsThe test are classified as follows:2.2.1 Routine testsRoutine tests are the following:a)external inspection (2.14.2);b)voltage test between terminals (2.5.2);c)voltage test between terminals and case (2.6.1);d)capacitance and tan d measurements (2.3);e)test of internal discharge device (2.7);f)sealing test (2.8).Routine tests shall be carried out by the manufacturer on every capacitor before delivery.At his request, the purchaser shall be supplied with a certificate detailing the results of suchtests.The sequence of the tests is as indicated.2.2.2 Type testsUnless otherwise specified, every capacitor sample to which it is intended to apply the type testshall first have withstood satisfactorily the application of all the routine tests.Type tests are the following:a)mechanical tests (2.14);b)voltage test between terminals (2.5.3);c)voltage test between terminals and case (2.6.2);d)surge discharge test (2.9);
61881 © IEC:1999– 25 –e)self-healing test (2.11);f)environmental testing (2.13); mechanical testing (2.14);g)capacitor tangent of the loss angle (tan d) measurement (2.4);h)thermal stability test (2.10);i)test of internal discharge device (2.7);j)resonance frequency measurement (2.12);k)endurance test between terminals (2.15);l)disconnection test on fuses (2.17);m)destruction test (2.16).Type tests are intended to prove the soundness of the design of the capacitor and its suitabilityfor operation under the considerations detailed in this standard.The type tests shall be carried out by the manufacturer, and the purchaser shall, on request, besupplied with a certificate, detailing the results of such tests.These tests shall be made upon a capacitor of a design identical to that of the capacitor undercontract, or on a capacitor of a design that gives during the test the same or more severe testconditions.It is not essential that all type tests be carried out on the same capacitor sample.2.2.3 Acceptance testsThe routine and/or type test, or some of them, may be carried out by the manufacturer, onagreement with the purchaser.The number of samples that may be subjected to such repeat tests, the acceptance criteria, aswell as permission to deliver any of these units shall be subject to agreement between themanufacturer and the purchaser, and shall be stated in the contract.2.3 Capacitance and tan dd measurements (routine test)2.3.1 Measuring procedureThe capacitance and tan d shall be measured at a voltage and at a frequency chosen by themanufacturer.The method used shall not include errors due to harmonics or to accessories external to thecapacitor to be measured, such as reactors and blocking circuits in the measuring circuit.The accuracy of the measuring method shall be given and shall be better than 0,2 % forcapacitance and 10 % for tan d but not necessarily better than 1 ´ 10–4 if the measurement ismade at 50-60 Hz.The capacitance measurement shall be carried out after the voltage test between terminals(see 2.5).For capacitors with internal fuses, capacitance measurement shall also be made before thevoltage tests.
61881 © IEC:1999– 27 –2.3.2 Capacitance tolerancesIf not otherwise specified, the capacitance measured shall not differ from the rated capacitanceby more than –10 % to +10 %.2.3.3 Loss requirements (tan dd)The requirements regarding capacitor losses may be agreed upon between the manufacturerand the purchaser.NOTE – The manufacturer s
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