IEC 60255-26:2008

IEC 60255-26
Edition 2.0 2008-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Measuring relays and protection equipment –
Part 26: Electromagnetic compatibility requirements

Relais de mesure et dispositifs de protection –
Partie 26: Exigences de compatibilité électromagnétique

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IEC 60255-26
Edition 2.0 2008-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Measuring relays and protection equipment –
Part 26: Electromagnetic compatibility requirements

Relais de mesure et dispositifs de protection –
Partie 26: Exigences de compatibilité électromagnétique

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
N
CODE PRIX
ICS 29.120.70; 33.100.10; 33.100.20 ISBN 2-8318-9853-6
– 2 – 60255-26 © IEC:2008
CONTENTS
FOREWORD.3
INTRODUCTION.5
1 Scope and object.6
1.1 Emission .6
1.2 Immunity .6
2 Normative references .7
3 Terms and definitions .8
4 Test requirements and procedures .9
4.1 Emission tests.9
4.2 Immunity tests.9
5 Criteria for acceptance .9
5.1 Emission tests.9
5.2 Immunity tests.9
6 Test report.9

Figure 1 – Ports for measuring relays and protection equipment .9

Table 1 – Emission tests – Enclosure port .9
Table 2 – Emission tests – Auxiliary power supply port .10
Table 3 – Immunity tests – Enclosure port .10
Table 4 – Immunity tests – Auxiliary power supply port .11
Table 5 – Immunity tests – Communication port.12
Table 6 – Immunity tests – Input and output ports.13
Table 7 – Immunity tests – Functional earth port.14

60255-26 © IEC:2008 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MEASURING RELAYS AND PROTECTION EQUIPMENT –

Part 26: Electromagnetic compatibility requirements

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
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with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 60255-26 has been prepared by IEC technical committee 95:
Measuring relays and protection equipment.
This second edition cancels and replaces the first edition published in 2004. This edition
constitutes a technical revision.
The main difference with respect to the previous edition concerns the reference to IEC 61000-
4 series and to CISPR 22.
The text of this standard is based on the following documents:
FDIS Report on voting
95/230/FDIS 95/234/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – 60255-26 © IEC:2008
A list of all parts of IEC 60255 series under the general title Measuring relays and protection
equipment, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in
the data related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
60255-26 © IEC:2008 – 5 –
INTRODUCTION
This part of IEC 60255 specifies all of the requirements for electromagnetic compatibility in a
single document. As such, it is considered as an overview document for measuring relays and
protection equipment. The detailed test procedures are given in other referenced standards.

– 6 – 60255-26 © IEC:2008
MEASURING RELAYS AND PROTECTION EQUIPMENT –

Part 26: Electromagnetic compatibility requirements

1 Scope and object
This part of IEC 60255 is applicable to measuring relays and protection equipment for power
system protection, including the control, monitoring and process interface equipment used
with those systems.
This standard specifies the essential requirements for electromagnetic compatibility for
measuring relays and protection equipment intended to be used at industrial locations.
Measuring relays and protection equipment used in substations and power plants may require
higher immunity test levels.
For equipment not incorporating electronic circuits, for example electromechanical relays,
tests according to this standard are not required.
The requirements specified in this standard are applicable to measuring relays and protection
equipment in a new condition and all tests specified are type tests only.
1.1 Emission
The object of this standard is to specify limits and test methods, for measuring relays and
protection equipment in relation to electromagnetic emissions which may cause interference
in other equipment.
These emission limits represent electromagnetic compatibility essential requirements and
have been selected to ensure that the disturbances generated by measuring relays and
protection equipment, operated normally in substations and power plants, do not exceed a
level which could prevent other equipment from operating as intended.
Test requirements are specified for the enclosure and power supply ports.
1.2 Immunity
The object of this standard is to specify the essential immunity test requirements for
measuring relays and protection equipment in relation to continuous and transient, conducted
and radiated disturbances, including electrostatic discharges.
These test requirements represent the essential electromagnetic compatibility immunity
requirements selected to ensure an adequate level of immunity for measuring relays and
protection equipment.
NOTE 1 Safety considerations are not covered in this standard.
NOTE 2 In special cases, situations will arise where the levels of disturbance may exceed the levels specified in
this standard, for example where a hand-held transmitter is used in close proximity to measuring relays and
protection equipment. In these instances, special precautions may have to be employed.

60255-26 © IEC:2008 – 7 –
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced document (including any amendments) applies.
IEC 60255-11:1979, Electrical relays – Part 11: Interruptions to and alternating component
(ripple) in d.c. auxiliary energizing quantity of measuring relays
IEC 60255-22-1:2007, Measuring relays and protection equipment – Part 22-1: Electrical
disturbance tests – 1 MHz burst immunity tests
IEC 60255-22-2:1996, Electrical relays – Part 22: Electrical disturbance tests for measuring
relays and protection equipment – Section 2: Electrostatic discharge tests
IEC 60255-22-3:2007, Measuring relays and protection equipment – Part 22-3: Electrical
disturbance tests – Radiated electromagnetic field immunity
IEC 60255-22-4:2002, Electrical relays – Part 22-4: Electrical disturbance tests for measuring
relays and protection equipment – Electrical fast transient/burst immunity test
IEC 60255-22-5:2002, Electrical relays – Part 22-5: Electrical disturbance tests for measuring
relays and protection equipment – Surge immunity test
IEC 60255-22-6:2001, Electrical relays – Part 22-6: Electrical disturbance tests for measuring
relays and protection equipment – Immunity to conducted disturbances induced by radio
frequency fields
IEC 60255-22-7:2003, Electrical relays – Part 22-7: Electrical disturbance tests for measuring
relays and protection equipment – Power frequency immunity tests
IEC 60255-25:2000, Electrical relays – Part 25: Electromagnetic emission tests for measuring
relays and protection equipment
CISPR 22:2006, Information technology equipment – Radio disturbance characteristics –
Limits and methods of measurement
IEC 61000-4-2:2001, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3 : Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4:2004, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
IEC 61000-4-6:2006, Electromagnetic compatibility (EMC) – Part 4-6: Testing and
measurement techniques – Immunity to conducted disturbances, induced by radio-frequency
fields
IEC 61000-4-8:2001, Electromagnetic compatibility (EMC) – Part 4-8: Testing and
measurement techniques – Power frequency magnetic field immunity test

– 8 – 60255-26 © IEC:2008
IEC 61000-4-16:2002, Electromagnetic compatibility (EMC) – Part 4-16: Testing and
measurement techniques – Test for immunity to conducted, common mode disturbances in
the frequency range 0 Hz to 150 kHz
IEC 61000-4-18:2006, Electromagnetic compatibility (EMC) – Part 4-18: Testing and
measurement techniques – Damped oscillatory wave immunity test
IEC 61000-4-29:2000, Electromagnetic compatibility (EMC) – Part 4-29: Testing and
measurement techniques – Voltage dips, short interruptions and voltage variations on d.c.
input power port immunity tests
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
auxiliary power supply port
a.c or d.c auxiliary energising input of the Equipment Under Test (EUT)
3.2
communication port
interface with a communication and/or control system, using low energy signals, permanently
connected to the EUT
3.3
enclosure port
physical boundary of the EUT through which electromagnetic fields may radiate or impinge
3.4
Equipment Under Test
EUT
equipment which may be either a measuring relay or a protection equipment
3.5
functional earth port
port on the EUT which is connected to earth for purposes other than electrical safety
3.6
input port
port through which the EUT is energised or controlled in order to perform its function(s), for
example current and voltage transformer, binary (status), etc.
3.7
output port
port through which the EUT produces predetermined changes, for example contacts,
optocouplers, analogue output, etc.
3.8
port
particular interface of the specified EUT with the external electromagnetic environment (see
Figure 1).
60255-26 © IEC:2008 – 9 –
Enclosure port
Auxiliary power supply port Functional earth port
Output port
EUT
Input port Communication port
IEC  896/08
Figure 1 – Ports for measuring relays and protection equipment
4 Test requirements and procedures
4.1 Emission tests
The requirements and procedures for conducted and radiated emission tests are specified in
Table 1 and Table 2.
4.2 Immunity tests
The requirements and procedures for immunity tests are specified in Table 3 to Table 7.
5 Criteria for acceptance
5.1 Emission tests
The measured values shall be below the levels specified in Table 1 and Table 2.
5.2 Immunity tests
The criteria for acceptance shall be as specified in the documents given in Table 3 to Table 7.
After the tests, the EUT shall still comply with the relevant performance specifications.
6 Test report
The test report shall be in accordance with that given in the relevant IEC 60255 series of
standards if required, and this test report shall always be produced.
NOTE The item numbers in Tables 1, 2, 3, 4, 5, 6 and 7 are given for reference purposes and should be used in
the test report.
Table 1 – Emission tests – Enclosure port
Environmental a Basic Test
Item Frequency range Limits
phenomena standard procedure
30 MHz – 230 MHz 40 dB(μV/m) quasi peak
1.1 Radiated emission CISPR 22 IEC 60255-25
230 MHz – 1 000 MHz
47 dB(μV/m) quasi peak
a
The limits given in this table are measured at a distance of 10 m.

– 10 – 60255-26 © IEC:2008
Table 2 – Emission tests – Auxiliary power supply port
Environmental Basic Test
Item Frequency range Limits
phenomena standard procedure
79 dB(μV) quasi peak
0,15 MHz – 0,50 MHz
66 dB(μV) average
73 dB(μV) quasi peak
Conducted
2.1 CISPR 22 IEC 60255-25
0,5 MHz – 5 MHz
emission
60 dB(μV) average
73 dB(μV) quasi peak
5 MHz – 30 MHz
60 dB(μV) average
Table 3 – Immunity tests – Enclosure port
Item
Environmental Test Units Basic Test
phenomena specification standard procedure and
acceptance
criteria
Radiated radio 80 – 1 000 and MHz
frequency 1 400 – 2 700
electromagnetic IEC IEC
10 V/m unmodulated, r.m.s.
3.1
field
61000-4-3 60255-22-3
Amplitude 80 % AM (1 kHz)
modulated
Electrostatic
discharge
IEC IEC
3.2
Contact 6 kV (charge voltage)
61000-4-2 60255-22-2
Air 8 kV (charge voltage)
Power frequency 50, 60 Hz
IEC IEC
magnetic field
3.3 30 A/m (continuous)
61000-4-8 61000-4-8
300 A/m (1 to 3 s)
60255-26 © IEC:2008 – 11 –
Table 4 – Immunity tests – Auxiliary power supply port
Item Environmental Test specification Units Basic Test
phenomena standard procedure and
acceptance
criteria
Conducted 0,15 – 80 MHz
disturbance
10 V unmodulated, r.m.s.
induced by radio-
IEC IEC
4.1 150
Ω Source impedance
frequency fields
61000-4-6 60255-22-6
80 % AM (1 kHz)
Amplitude
modulated
Fast transients 5 / 50 ns T / T
R H
Class A 4 kV peak voltage
IEC IEC
4.2
5 kHz repetition frequency
61000-4-4 60255-22-4
Class B 2 kV peak voltage
5 kHz repetition frequency
1 MHz
1 MHz oscillatory
waves
75 ns T
R
IEC IEC
400 Hz repetition frequency
4.3
61000-4-18 60255-22-1
Ω Source impedance
Differential mode 1 kV peak voltage
Common mode 2,5 kV peak voltage
Surge 1,2 / 50 (8 / 20)
μs T / T voltage
R H
(current)
Ω Source impedance
Line-to-line 0,5 1 kV charge voltage
IEC IEC
Ω coupling resistor
4.4
61000-4-5 60255-22-5
18 μF coupling capacitor
Line-to-earth 0,5 1 2 kV charge voltage
10 Ω coupling resistor
μF coupling capacitor
d.c. voltage 100 % reduction
IEC IEC
interruption
4.5
61000-4-29 60255-11
5, 10, 20, 50, 100, 200 ms interruption time

– 12 – 60255-26 © IEC:2008
Table 5 – Immunity tests – Communication port
Item Environmental Test specification Units Basic Test
phenomena standard procedure and
acceptance
criteria
Conducted 0,15 – 80 MHz
disturbance
10 V unmodulated, r.m.s.
induced by radio- IEC IEC
5.1
Ω Source impedance
frequency fields
61000-4-6 60255-22-6
Amplitude 80 % AM (1 kHz)
modulated
Fast transients 5 / 50 ns T / T
R H
Class A 2 kV peak voltage
IEC IEC
5.2 5 kHz repetition frequency
61000-4-4 60255-22-4
Class B 1 kV peak voltage
5 kHz repetition frequency
1 MHz oscillatory 1 MHz
waves
75 ns T
R
IEC IEC
400 Hz repetition frequency
5.3
61000-4-18 60255-22-1
200 Ω source impedance
Differential mode 0 kV peak voltage
Common mode 1 kV peak voltage
Surge 1,2 / 50
μs T / T voltage
R H
8 / 20
μs T / T current
R H
2 IEC IEC
Ω source impedance
5.4
61000-4-5 60255-22-5
Line-to-earth 0,5 1 kV charge voltage
Ω coupling resistor
0 μF coupling capacitor
60255-26 © IEC:2008 – 13 –
Table 6 – Immunity tests – Input and output ports
Item Environmental Test specification Units Basic Test
phenomena standard procedure and
acceptance
criteria
Conducted 0,15 – 80 MHz
disturbance
10 V unmodulated, r.m.s.
induced by
IEC IEC
Ω source impedance
radiofrequency
6.1
61000-4-6 60255-22-6
fields
Amplitude 80 % AM (1 kHz)
modulated
Fast transients 5 / 50 ns T / T
R H
Class A 4 kV peak voltage
IEC IEC
6.2 5 kHz repetition frequency
61000-4-4 60255-22-4
Class B 2 kV peak voltage
5 kHz repetition frequency
1 MHz oscillatory 1 MHz
waves
75 ns T
R
IEC IEC
400 Hz repetition frequency
6.3
61000-4-18 60255-22-1
Ω source impedance
Differential mode 1 kV peak voltage
Common mode 2,5 kV peak voltage
Surge 1,2 / 50 (8 / 20) μs T / T voltage
R H
(current)
2 Ω source impedance
Line-to-line 0,5 1 kV charge voltage
IEC IEC
6.4 Ω coupling resistor
61000-4-5 60255-22
...