SIST IEC 60255-21-3:1995

• Abstract:

  Specifies the vibration, shock, bump and seismic tests applicable to electromechanical and static measuring relays and protection equipment, with or without output contacts.

• Status: Published
• Publication Date: 31-Jul-1995
• ICS: 29.120.40 - Switches
• ICS: 29.120.70 - Relays
• Technical Committee: ISS EIT.ERE - All-or-nothing electrical relays
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Aug-1995
• Due Date: 01-Aug-1995
• Completion Date: 01-Aug-1995
• Ref Project: IEC 60132-3A:1965 - Rotary wafer switches (low current rating) - Part 3: Rotary wafer switches with two-hole mounting - First supplement

SIST IEC 60255-21-3:1995 is the Slovenian adoption of IEC 60255-21-3 from the International Electrotechnical Commission (IEC). It specifies seismic tests for electromechanical and static measuring relays and protection equipment, with or without output contacts. Engineers, manufacturers, and test laboratories use it to check whether this equipment can withstand earthquake-type mechanical stress without maloperation.

What does SIST IEC 60255-21-3:1995 specify?

SIST IEC 60255-21-3:1995 sets out seismic testing for measuring relays and protection equipment in new condition. The document is part of the IEC 60255-21 series on vibration, shock, bump, and seismic tests.

The standard is organized around two alternative seismic test methods, followed by class selection, test procedures, and acceptance criteria:

Annex	What it covers
Annex A	Seismic tests choice criteria, including guidance on when to use the different methods

The main body covers:

• Scope and object
• Normative references
• Definitions
• Method A: single axis sine sweep seismic test
• Method B: biaxial multi-frequency random seismic test
• Selection of severity classes
• Test procedures
• Criteria for acceptance

What are the key requirements of SIST IEC 60255-21-3:1995?

SIST IEC 60255-21-3:1995 gives two alternative seismic test methods, and neither is identified as the reference method. In practice, the manufacturer and user must agree on the method and severity class that match the intended service environment.

Test method choice and severity classes

The standard provides three severity classes, 0, 1, and 2. Class 0 means no seismic test applies; class 1 is for normal use in power plants, substations, and industrial plants; class 2 is for equipment needing a very high margin of security or exposed to very high seismic shock.

Method A - single axis sine sweep

Method A uses a single axis sine sweep over the nominal range from 1 Hz to 35 Hz. The specimen is mounted as in service, the sweep is continuous and exponential, and the sweep rate is 1 octave per minute within a stated tolerance. This matters because the equipment must be tested in a way that reflects how it is actually installed and loaded.

The method also controls transverse motion, distortion, amplitude tolerance, and mounting rigidity. For a buyer or test lab, this means the fixture, cabling, and reference point matter as much as the relay itself, because poor mounting can change the test result.

Method B - biaxial multi-frequency random seismic test

Method B applies biaxial motion using a multi-frequency random seismic input matched to a standard response spectrum. The standard assumes 5 % damping, uses a 1 Hz to 35 Hz nominal range, and requires a defined time-history duration and strong part of the record.

This method limits unwanted transverse motion and requires the test response spectrum to be checked in 1/6 octave bands. In practice, it is the more realistic option when coupling between axes is important.

Test setup and operating condition

During testing, the relay or protection equipment is operated under reference conditions from the relevant IEC 255 series standard. Auxiliary energizing quantities are rated values, output circuits are normally unloaded except for the monitoring device, and input quantities are set around the operate value to check both no-operate and no-release behavior.

The equipment is tested with its case and cover in place, and any transportation restraints removed. That means the test reflects the installed product, not a stripped-down laboratory assembly.

Acceptance

The equipment shall not maloperate during the test, and a change of output state for more than 2 ms counts as maloperation. After testing, it must still meet the relevant performance specification, keep its settings within the stated limit, and show no mechanical damage.

What terms does SIST IEC 60255-21-3:1995 define?

SIST IEC 60255-21-3:1995 defines the terms it uses for seismic testing and response measurement.

• Single axis sine sweep seismic test - a test where sinusoidal vibration is applied in each orthogonal axis in turn.
• Biaxial test - a test where horizontal and vertical stresses are applied at the same time.
• Biaxial multi-frequency random seismic test - a random-motion test designed to reproduce the standard response spectrum.
• Standard response spectrum - the reference spectrum shape used for method B.
• Zero period acceleration (ZPA) - the high-frequency asymptotic acceleration value of the response spectrum.
• Time-history - the record of acceleration, displacement, or velocity versus time.
• Strong part of the time-history - the part of the record between the two 25 % crossings of the maximum value.

Who uses SIST IEC 60255-21-3:1995?

SIST IEC 60255-21-3:1995 is used by manufacturers of measuring relays and protection equipment, by type-test laboratories, and by utilities or industrial buyers specifying equipment for seismic areas. It is also used by engineers who need to select a test severity class, define mounting conditions, or check acceptance after environmental qualification.

Which standards are used with SIST IEC 60255-21-3:1995?

SIST IEC 60255-21-3:1995 refers to these related standards and documents:

• IEC 50 - provides the general electrotechnical vocabulary used for terminology.
• IEC 68-2-6 - gives guidance on sinusoidal vibration testing.
• IEC 68-2-57 - covers the time-history vibration method used as a reference for random motion.
• IEC 68-3-3 - gives guidance on seismic test methods for equipment.
• IEC 255-21-1 - supplies vibration test terminology and the definition of distortion used here.
• IEC 255-21-2 - covers shock and bump tests in the same relay series.
• ISO 2041 - provides vibration and shock vocabulary.

What does the SIST IEC 60255-21-3:1995 document contain?

SIST IEC 60255-21-3:1995 contains the standard response spectrum shape, a typical time-history, and an acceleration-versus-frequency plot for the sine sweep method. It also includes tables that set out the severity class parameters and guide class selection.

Annex A explains why two test methods are retained and gives practical choice criteria, including the role of damping and engineering judgment. For users, the document is mainly a qualification and type-test specification: it tells them how to set up the test, what to monitor, and how to decide whether the relay or protection equipment has passed.

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Electrical relays - Part 21: Vibration, shock, bump and seismic tests on measuring relays and protection equipment - Section 3: Seismic testsRelais électriques - Partie 21: Essais de vibrations, de chocs, de secousses et de tenue aux séismes applicables aux relais de mesure et aux dispositifs de protection - Section 3: Essais de tenue aux séismesElectrical relays - Part 21: Vibration, shock, bump and seismic tests on measuring relays and protection equipment - Section 3: Seismic tests29.120.70RelejiRelaysICS:Ta slovenski standard je istoveten z:IEC 60255-21-3SIST IEC 60255-21-3:1995en01-avgust-1995SIST IEC 60255-21-3:1995SLOVENSKI
STANDARD
CODE PRIXPRICE CODENNORMECEIINTERNATIONALEIECINTERNATIONAL255-21-3STANDARDPremière éditionFirst edition1993-09Relais électriques —Partie 21:Essais de vibrations, de chocs, de secousseset de tenue aux séismes applicables aux relaisde mesure et aux dispositifs de protection -Section 3: Essais de tenue aux séismesElectrical relays —Part 21:Vibration, shock, bump and seismic testson measuring relays and protection equipment —Section 3: Seismic tests© CEI 1993 Droits de reproduction réservés — Copyright — all rights reservedAucune partie de cette publication ne peut 'être reproduite niutilisée sous quelque forme que ce soit et par aucun pro-cédé, électronique ou mécanique, y compris la photocopie etles microfilms, sans l'accord écrit de l'éditeur.No part of this publication may be reproduced or utilized inany form or by any means, electronic or mechanical,including photocopying and microfilm, without permissionin writing from the publisher.Bureau Central de la Commission Electrotechnique Internationale 3, rue de Varembé Genève, SuisseCommission Electrotechnique InternationaleFor price, see current catalogueIEC International Electrotechnical CommissionMemayHapoAHan 3neKrporexHH4ecHaFi KoMHCCHR• Pour prix, voir catalogue en vigueurSIST IEC 60255-21-3:1995

255-21-3 © IEC:1993- 3 -CONTENTSPageFOREWORDClause1Scope and object72 Normative references73Definitions93.1Single axis sine sweep seismic test93.2Biaxial test 93.3Biaxial multi-frequency random seismic test113.4 Standard response spectrum
113.5 Damping 113.6 Zero period acceleration 113.7 Random motion sample 113.8 Time-history113.9Strong part of the time-history114Requirements for single axis sine sweep seismic test (method A)114.1Main parameters 114.2 Test apparatus and mounting 134.3 Test severity classes155Requirements for biaxial multi-frequency random seismic test (method B)155.1Main parameters 155.2 Test apparatus and mounting 175.3 Test severity classes195.4Biaxial conditioning19Selection of test severity classes216.1Recommendations for selection of test classes216.2Identification of test method and severity class217 Test procedures 218Criteria for acceptance 23Figures1Multi-frequency broad-band standard response spectrum shape 252Typical time-history253Acceleration versus frequency for the single axis sine sweep seismic test27Annex A - Seismic tests choice criteria 29SIST IEC 60255-21-3:1995

255-21-3 ©IEC:1993– 5 –INTERNATIONAL ELECTROTECHNICAL COMMISSIONELECTRICAL RELAYS —Part 21: Vibration, shock, bump and seismic testson measuring relays and protection equipment —Section 3: Seismic testsFOREWORD1)The IEC (International Electrotechnical Commission) is a worldwide organization for standardizationcomprising all national electrotechnical committees (IEC National Committees). The object of the IEC is topromote international cooperation on all questions concerning standardization in the electrical andelectronic fields. To this end and in addition to other activities, the IEC publishes International Standards.Their preparation is entrusted to technical committees; any IEC National Committee interested inthe subject dealt with may participate in this preparatory work. International, governmental andnon-governmental organizations liaising with the IEC also participate in this preparation. The IECcollaborates closely with the International Organization for Standardization (ISO) in accordance withconditions determined by agreement between the two organizations.2)The formal decisions or agreements of the IEC on technical matters, prepared by technical committees onwhich all the National Committees having a special interest therein are represented, express, as nearly aspossible, an international consensus of opinion on the subjects dealt with.3)They have the form of recommendations for international use published in the form of standards, technicalreports or guides and they are accepted by the National Committees 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.International Standard IEC 255-21-3 has been prepared by IEC technical committee 95:Measuring relays and protection equipment.The text of this standard is based on the following documents:DISReport on VotingAmendment to DISReport on Voting41 B(CO)54*41 B(CO)5741 B(CO)5841 B(CO)69Full information on the voting for the approval of this standard can be found in the reporton voting indicated in the above table.Annex A is for information only.* Subcommittee 41 B has been changed into new technical committee 95.SIST IEC 60255-21-3:1995

255-21-3 ©IEC:1993- 7 -ELECTRICAL RELAYS —Part 21: Vibration, shock, bump and seismic testson measuring relays and protection equipment —Section 3: Seismic tests1 Scope and objectThis International standard is one of a series of parts specifying the vibration, shock,bump and seismic requirements applicable to electromechanical and static measuringrelays and protection equipment, with or without output contacts.This standard includes two alternative types of seismic tests (see annex A):-the single axis sine sweep seismic test (method A); and-the biaxial multi-frequency random seismic test (method B).During preparation of this standard, it was determined that the number of countries inwhich the first test method was preferred was about equal to the number of countries inwhich the second method was preferred. For this reason both methods have beenretained, and neither have been identified as reference (or "referee") method.The requirements of this standard are applicable only to measuring relays and protectionequipment in a new condition.The tests specified in this standard are type tests.The object of this standard is to state:-definitions of terms used;-test conditions;-standard test severity classes;-test procedures;-criteria for acceptance.2 Normative referencesThe following normative documents contain provisions which, through reference in thistext, constitute provisions of this International Standard. At the time of publication, theeditions indicated were valid. All normative documents are subject to revision, and partiesto agreements based on this International Standard are encouraged to investigate thepossibility of applying the most recent editions of the normative documents indicatedbelow. Members of IEC and ISO maintain registers of currently valid InternationalStandards.SIST IEC 60255-21-3:1995

255-21-3 ©IEC:1993- 9 -IEC 50: International Electrotechnical Vocabulary (IEV)IEC 68-2-6: 1982, Environmental testing - Part 2: Tests - Test Fc and guidance: Vibration(sinusoidal)IEC 68-2-57: 1989, Environmental testing - Part 2: Tests - Test Ff: Vibration - Time-history methodIEC 68-3-3: 1991, Environmental testing - Part 3: Guidance - Seismic test methods forequipmentsIEC 255-21-1: 1988, Electrical relays - Part 21: Vibration, shock, bump and seismic testson measuring relays and protection equipment - Section 1: Vibration tests (sinusoidal)IEC 255-21-2: 1988: Electrical relays - Part 21: Vibration, shock, bump and seismic testson measuring relays and protection equipment - Section 2: Shock and bump testsISO 2041: 1990, Vibration and shock - Vocabulary3 DefinitionsFor definitions of general terms not defined in this standard, reference should be made to:-IEC International Electrotechnical Vocabulary (IEV) (IEC 50)-IEC 68-2-6, IEC 68-2-57, and IEC 68-3-3;-IEC relay standards published in the IEC 255 series and in particular IEC 255-21-1and IEC 255-21-2;-ISO 2041.3.1 Single axis sine sweep seismic testA test during which a specimen is submitted to sweeps of sinusoidal vibration in the threeorthogonal axes of the specimen in turn, in terms of constant displacement and/orconstant acceleration, within a standard frequency range.NOTE – The term specimen includes any auxiliary part which is an integral functional feature of the measur-ing relay protection equipment under test.3.2 Biaxial testA test during which a specimen is submitted to stresses in the horizontal and vertical axessimultaneously.SIST IEC 60255-21-3:1995

255-21-3 © IEC:1993— 11 —3.3 Biaxial multi-frequency random seismic testA test during which a specimen is submitted to a random sequence of stresses with a testresponse spectrum which reproduces the standard response spectrum by a biaxial multi-frequency input motion.3.4 Standard response spectrumA response spectrum whose shape shall be according to figure 1, and whose mainparameters are the damping and the zero period acceleration defined below.3.5 DampingA generic term ascribed to the numerous energy dissipation mechanisms in a system.In practice, damping depends on many parameters such as construction, mode of vibra-tion, strain, applied forces, velocity, materials, joint slippage, etc.3.6 Zero period accelerationHigh frequency asymptotic value of acceleration of the response spectrum (see figure 1).NOTE – The zero period acceleration is of practical significance as it represents the largest peak value ofacceleration in a time-history. This is not to be confused with the peak value of acceleration in theresponse spectrum.3.7 Random motion sampleSample of random motion record modified in frequency range and amplitude so as toproduce the required or the standard response spectrum.3.8 Time-historyRecording, as a function of time, of acceleration or displacement or velocity, resulting froma given event (see figure 2).3.9 Strong part of the time-historyThe strong part of the time-history is the part of the time-history from the time when theplot first reaches 25 % of the maximum value to the time when it reaches for the last timethe 25 % level(see figure 2).4 Requirements for single axis sine sweep seismic test (method A)4.1 Main parametersThe main parameters of the single axis sine sweep seismic test are the following:—frequency range;-acceleration;—displacement amplitude below the cross-over frequency;-sweep rate and number of sweep cycles.SIST IEC 60255-21-3:1995

255-21-3 ©IEC:1993– 13 –4.2 Test apparatus and mountingThe required characteristics of the vibration generator and fixture, together with the mount-ing requirements, shall be as follows. The characteristics apply when the specimen ismounted on the generator.4.2.1 Basic motionThe basic motion shall be a sinusoidal function of time, and such that the fixing point ofthe specimen moves substantially in phase and in straight parallel lines along a specifiedaxis, subject to the requirements of 4.2.2 and 4.2.3.4.2.2 Transverse motionThe maximum vibration amplitude at the check points in any axis perpendicular to thespecified axis shall not exceed 50 % of the specified amplitude.4.2.3 DistortionThe acceleration distortion measurement shall be carried out at the reference point, whichshall be declared by the manufacturer.The distortion, as defined in 3.9 of IEC 255-21-1, shall not exceed 25 %. In cases where adistortion value greater than 25 % is obtained, the distortion shall be noted, and agreedbetween manufacturer and user.4.2.4 Vibration amplitude tolerancesThe actual vibration displacement and acceleration amplitude along the required axis ofthe reference point shall be equal to the specified value, within a tolerance of ±15 %.4.2.5 Frequency range tolerancesThe frequency range shall be equal to the specified values (see 4.3 and 5.2.4) within thefollowing tolerances:±0,2 Hz, for the lower frequency 1 Hz;±1 Hz, for the upper frequency 35 Hz.4.2.6 SweepThe sweeping shall be continuous and the frequency shall change exponentially with time.The sweep rate shall be 1 octave per min ± 10 %.4.2.7 MountingThe specimen shall be fastened to the vibration generator or fixture by its normal meansof attachment in service so that the gravitat
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