SIST IEC 60255-13:1995

• Abstract:

  Specifies performance requirements for the subfamily. Forms part of a series dealing with measuring relays with more than one input energizing quantity and for which IEC 60255-6 gives the general requirements.

• 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 60132-1:1962 - Rotary wafer switches (low current rating). Part 1: General requirements and measuring methods

SIST IEC 60255-13:1995 is the Slovenian standard identical to IEC 60255-13 for biased (percentage) differential relays. It specifies performance requirements and methods of presenting characteristics for electrically biased differential relays used mainly to detect faults in a.c. generators, motors and transformers. It is intended for manufacturers, test laboratories, and users who need to declare, compare, and verify relay behavior.

What does SIST IEC 60255-13:1995 specify?

SIST IEC 60255-13:1995 specifies the performance requirements, declared data, presentation methods, and type test methods for biased (percentage) differential relays. It is part of the IEC series for measuring relays with more than one input energizing quantity and uses IEC Publication 255-6 for the general requirements of that family.

The standard is organized into three sections:

• Section One - Scope and Definitions
• Section Two - Requirements
• Section Three - Test Methods

It applies to relays in new condition, and all tests in this standard are type tests. The scope excludes relays for busbar protection and current differential relays such as pilot wire relays used for transmission line protection.

What are the key requirements of SIST IEC 60255-13:1995?

SIST IEC 60255-13:1995 focuses on what the manufacturer must declare, how the relay characteristic is described, and how compliance is checked. In practice, it tells the buyer or test engineer which relay data must be available and which companion IEC publications carry the general test requirements.

• Clause 3, standard values - Input and auxiliary energizing quantities and frequency follow IEC Publication 255-6. The manufacturer also declares characteristic quantities, setting ranges, restraint percentage, and resetting and disengaging ratios, because there are no standard rated values for those items.
• Clause 4, operation and accuracy - The manufacturer declares the operating characteristic, the effective range of restraint current, the maximum through current, and any harmonic restraint behavior. The maximum through current declaration matters because the relay shall withstand sudden application and removal of that current for at least 100 ms.
• Clause 5, presentation of characteristics - The standard gives recommended ways to present operating characteristics, operating time, and harmonic restraint, including graphical forms in Figures 1 to 3. This helps users compare relays and check setting ranges without reading each design differently.
• Clauses 6 to 9 and 12 to 14 - Thermal, mechanical, auxiliary energizing, shock and vibration, contact performance, insulation, markings and data, and high-frequency disturbance follow companion IEC publications. If the differential circuit has lower thermal capability than the restraint circuit, that capability must be declared, which matters for burden and overload decisions.
• Clause 11, rated burden - The manufacturer declares burden between appropriate input terminals both with no differential current and with differential current equal to input current. This gives a realistic view of loading in service and during test.
• Clauses 15 to 18, test methods - Tests are based on reference values for influencing quantities and rated auxiliary energizing quantities unless otherwise stated. For operating time tests, the relay is checked at three and ten times the operating value at minimum and maximum settings, and through-current tests and mechanical tests use the declared conditions.

What terms does SIST IEC 60255-13:1995 define?

SIST IEC 60255-13:1995 defines the core relay terms needed to read the requirements correctly.

• Differential relay - A relay designed to respond to differential current.
• Biased (or percentage) differential relay - A differential relay whose response is modified by a restraint current.
• Differential current - The phasor difference between specified incoming and outgoing currents.
• Restraint current - The combination of incoming and outgoing currents that restrains relay operation.
• Restraint percentage - The percentage relationship between differential current and restraint current(s) up to which the relay does not operate.
• Through current - The part of the total incoming current that is also present in the outgoing current.

Who uses SIST IEC 60255-13:1995?

SIST IEC 60255-13:1995 is used by relay manufacturers, protection engineers, test laboratories, and utility or industrial buyers. Manufacturers use it to declare relay settings and performance data, while test labs use it to run type tests for operating characteristic, operating time, thermal behavior, mechanical behavior, and through-current performance.

It is especially relevant for equipment used on a.c. generators, motors, and transformers. Quality managers and buyers use it to check whether a relay declaration, test report, or tender specification covers the required data and companion IEC references.

Which standards are used with SIST IEC 60255-13:1995?

SIST IEC 60255-13:1995 relies on these IEC publications:

• IEC Publication 255-6 - Provides general requirements for measuring relays with more than one input energizing quantity, including standard values and assigned errors.
• IEC Publication 255-6A - Provides the thermal, mechanical, auxiliary energizing, shock and vibration requirements and related test provisions.
• IEC Publication 255-0-20 - Provides contact performance requirements for electrical relays.
• IEC Publication 255-5 - Provides insulation tests for electrical relays.
• IEC International Electrotechnical Vocabulary (I.E.V.) - Provides general relay terminology when a term is not defined in this standard.

What does the SIST IEC 60255-13:1995 document contain?

SIST IEC 60255-13:1995 contains Table I and Table II for reference conditions and nominal range limits, plus Figures 1 to 4 for relay characteristics and test circuits. The figures show how to present the operate and non-operate zones, operating time, and harmonic restraint behavior.

The test section describes how to measure operating characteristic, operating time, harmonic restraint, thermal performance, through-current performance, and mechanical requirements. It also states the conditions for applying input and auxiliary quantities during tests, which makes the standard useful for design verification, type testing, and product comparison.

SLOVENSKI STANDARD
01-avgust-1995
Electrical relays - Part 13: Biased (percentage) differential relays
Electrical relays - Part 13: Biased (percentage) differential relays
Relais électriques - Treizième partie: Relais différentiels à pourcentage
Ta slovenski standard je istoveten z: IEC 60255-13
ICS:
29.120.70 Releji Relays
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

NORME
CEI
INTERNATIONALE IEC
255-13
INTERNATIONAL
Première édition
STANDARD
First edition
Relais électriques
Treizième partie:
Relais différentiels à pourcentage
Electrical relays
Part 13:
Biased (percentage)
differential relays
© CEI 1980 Droits de reproduction réservés
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— 3 —
CONTENTS
Page
FOREWORD 5
PREFACE
SECTION ONE — SCOPE AND DEFINITIONS
Clause
1. Scope 7
2. Definitions 7
SECTION Two — REQUIREMENTS
3. Standard values 9
4. Operation and accuracy
5. Methods of presenting relay characteristics and performance
6. Thermal requirements
7. Mechanical requirements
8. Values of the limits of the operative range of the auxiliary energizing quantities
9. Shock and vibration
10. Contact performance
11. Rated burden 17
12. Insulation 17
13. Markings and data 17
14. High-frequency disturbance test 17
SECTION THREE — TEST METHODS
15. Tests related to accuracy and operating characteristics
16. Tests for thermal requirements
17. Tests of performance with through current 21
18. Tests for mechanical requirements 21

INTERNATIONAL ELECTROTECHNICAL COMMISSION
ELECTRICAL RELAYS
Part 13: Biased (percentage) differential relays
FOREWORD
The formal decisions or agreements of the IEC on technical matters, prepared by Technical Committees on which all the
1)
National Committees having a special interest therein are represented, express, as nearly as possible. an international
consensus of opinion on the subjects dealt with.
They have the form of recommendations for international use and they are accepted by the National Committees in that
2)
sense.
In order to promote international unification, the IEC expresses the wish that all National Committees should adopt the
3)
text of the I EC recommendation for their national rules in so far as national conditions will permit. Any divergence
between the IEC recommendation and the corresponding national rules should, as far as possible, be clearly indicated in
the latter.
PREFACE
This standard has been prepared by Sub-Committee 41B: Measuring Relays, of IEC Technical Committee No. 41:
Electrical Relays.
Drafts were discussed at the meetings held Nice in 1976 and in Milan in 1977. A draft, Document 4lB(Central Office)13,
was submitted to the National Committees for approval under the Six Months' Rule in October 1978.
The National Committees of the following countries voted explicitly in favour of publication:
Korea (Democratic People's Republic of)
Australia
Norway
Austria
Poland
Belgium
Romania
Denmark
South Africa (Republic of)
France
Germany Sweden
Switzerland
Italy
Turkey
Japan
Korea (Republic of) United Kingdom
United States of America
Technical Committee No. 41 has decided to classify its future publications on a hierarchical basis as follows:
General standards;
First level:
Second level: Generic standards relating wholly or partly to a family of relays;
Third level: Standards applicable wholly or partly to a particular group of relays;
Fourth level: Particular requirements or specifications relating to a specific type (or pattern) of relay.
This standard, applicable .to a particular group of measuring relays with more than one input energizing quantity, is
hierarchically a third-level document.
Other IEC publications quoted in this standard:
Publications Nos. 255-0-20: Electrical Relays—Contact Performance of Electrical Relays.
Part 5: Insulation Tests for Electrical Relays.
255-5:
255-6: Part 6: Measuring Relays with More than One Input Energizing Quantity.
255-6A: First Supplement to Publication 255-6 (1978).

-7
ELECTRICAL RELAYS
Part 13: Biased (percentage) differential relays
SECTION ONE – SCOPE AND DEFINITIONS
1. Scope
This standard specifies the performance requirements of electrically biased (percentage)
differential relays. These relays constitute a particular sub-family of measuring relays with
more than one input energizing quantity as defined in IEC Publication 255-6, Electrical
Relays, Part 6: Measuring Relays with More than One Input Energizing Quantity, and the
parameters whose values are to be declared by the manufacturer of such relays. It also
specifies methods of presentation of the characteristics and performance of these relays.
This standard applies to relays designed for the detection of faults particularly in a.c.
generators, motors and transformers. It does not apply to relays designed for busbar
protection, nor does it apply to current differential (e.g. pilot wire) relays used for the
protection of transrhission lines. This standard covers the majority of biased (percentage)
differential relays and also, for example, those where the restraint percentage increases as the
through-current increases. For particular cases, supplementary requirements may be stated in
national standards.
All tests in this standard are type tests.
This standard applies only to relays in a new condition.
2. Definitions
For definitions of general terms not defined in this standard, reference should be made to
the IEC International Electrotechnical Vocabulary (I.E.V.), to IEC Publication 255-6, and
to IEC Publication 255-6A: First supplement to IEC Publication 255-6 (1978).
For the purpose of this standard, the following definitions shall apply:
2.1 Differential relay
A relay which, by its design, is intended to respond to differential current.
2.2 Biased (or percentage) differential relay
A differential relay in which the designed response is modified by a restraint current.
2.3 Differential current
In a differential relay, a current which is the phasor difference between specified incoming
and outgoing currents.
2.4 Restraint current
In a differential relay, the combination of incoming and outgoing currents, which restrains
operation of the relay.
9 —
2.5 Restraint percentage
The ratio, expressed as a percentage, between the differential current and the restraint
current(s) up to which the relay does not operate.
Note. — The definition of restraint percentage ignores an error, which may not be negligible, due to the finite
operating current required under zero restraint conditions. This may be taken into account when necessary.
2.6 Through current
In a differential relay, that portion of the total incoming current that is also present in the
outgoing current.
SECTION TWO — REQUIREMENTS
3. Standard values
Input and auxiliary energizing quantities and frequency
3.1
The standard values of input and auxiliary energizing quantities, and of frequency, are
specified in IEC Publication 255-6.
3.2 Standard reference values of influencing quantities and factors and standard values of their
nominal and extreme ranges
3.2.1 Influencing quantities and factors
The standard reference conditions are specified in Table I of IEC Publication 255-6. In
addition, the standard conditions given in Table I in this standard apply to biased
(percentage) differential relays.
TABLE I
Standard reference conditions and test tolerances of influencing quantities and factors
Influencing quantity or factor Reference conditions Test tolerances
the manufacturer or as specified in national
Input energizing currents As declared by
– Restraint current standards unless specified in clauses below or in lower-level
– Differential current documents
C. a)
Phase angle between input Zp
o° ±
energizing quantities
u a
U
,- CO
^ 2N
Zero
62-0 Transient
5% of peak a.c. value
(See note)
g d.c. component in a.c.
.2
U
As declared by the manufacturer or as specified in national
Setting value(s), where setting
adjustments are possible standards unless specified in clauses below or in lower-level
documents
Auxiliary Transient
Zero °
energizing d.c. component
/o of peak a.c. value
quantities in a.c. (See note)
Note. — In the special case of relays in which polyphase measurements are made on a single relay, the manufacturer
or national standards shall define which of the input currents shall be under reference conditions.

Limits of the nominal ranges of influencing quantities and factors
3.2.2
The standard values are specified in Table II of I E C Publication 255-6. In addition,
the standard values given in Table II in this standard apply to biased (percentage) differential
relays.
TABLE II
Standard values of the limits of the nominal ranges of influencing quantities and factors
Nominal range
Influencing quantity or factor
Reference input energizing quantity
Non-reference input energizing quantity
.2
Phase angle between input energizing quantities
a"
G
ca z
7.:
As declared by the manufacturer or as
^
specified in national standards
Frequency
c
.N
N
t
Waveform
m G
U
Steady-state d.c. component in a.c.
Transient d.c. component in a.c.
Voltage or current
As declared by the manufacturer or as
specified in national standards unless
_ " Frequency
specified in clauses below
cr Waveform
CL
.E
0 to 12% of the rated d.c. value')
a.c. component in d.c. (ripple)
':1
o
o
T
Steady state d.c. component in a.c.
As declared by the manufacturer or as
specified in national standards unless
specified in clauses below
Transient d.c. component in a.c.
This value of the tolerance is based on the definition given in the International Electrotechnical Vocabulary (I.E.V.
131-03-14) Peak ripple factor.
3.3 Characteristic quantity(ies) and setting range(s)
There are no standard rated values of either characteristic quantity(ies) or setting range(s).
The values and the limits of setting range(s) shall be declared by the manufacturer.
3.4 Restraint percentage
There are no standard values of restraint percentage. The setting values shall be declared
by the manufacturer.
— 13 —
3.5 Resetting and disengaging ratios
There are no standard values of the resetting and disengaging ratios. The values shall be
declared by the manufacturer.
4. Operation and accuracy
4.1 Operation
4.1.1 Operating characteristic
The manufacturer shall declare the operating characteristics of the relay under reference
conditions, these including the reference setting of the differential circuit, and at the maximum
and minimum settings of the restraint circuits, when applicable.
4.1.2 Effective range*
The manufacturer shall declare the effective range * of restraint current values.
4.1.3 Maximum through current
The manufacturer shall declare the maximum through current up to which the relay
produces no output. The relay shall be able to withstand the sudden application and removal
of through current up to this valu
...