IEC 60255-26:2023

IEC 60255-26 ®
Edition 4.0 2023-01
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 4.0 2023-01
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
INTERNATIONALE
ICS 29.120.70 ISBN 978-2-8322-6317-4

– 2 – IEC 60255-26:2023 © IEC 2023
CONTENTS
FOREWORD . 5
1 Scope . 7
1.1 General . 7
1.2 Emission . 7
1.3 Immunity . 7
2 Normative references . 7
3 Terms, definitions, and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Abbreviated terms . 12
4 Electromagnetic environmental levels . 13
4.1 General . 13
4.2 Zone A, severe electromagnetic environment . 13
4.3 Zone B, typical electromagnetic environment . 14
5 Emission. 14
5.1 Radiated emission . 14
5.2 Conducted emission . 15
6 Immunity. 16
6.1 Immunity of enclosure . 16
6.2 Immunity of auxiliary power supply port . 17
6.3 Immunity of signal/control port and wired network port . 20
6.4 Immunity of input and output ports . 21
6.5 Immunity of earth port . 24
7 Test set-up and procedures . 24
7.1 General . 24
7.2 Emission . 25
7.2.1 General . 25
7.2.2 Radiated emission . 26
7.2.3 Conducted emission . 26
7.3 Immunity . 26
7.3.1 General . 26
7.3.2 Electrostatic discharge immunity test . 28
7.3.3 Radiated electromagnetic field immunity test . 29
7.3.4 Electrical fast transient/burst immunity test . 31
7.3.5 Damped oscillatory wave immunity test . 32
7.3.6 Surge immunity test . 33
7.3.7 Conducted RF immunity test . 35
7.3.8 Conducted power frequency immunity test on binary inputs . 37
7.3.9 Power frequency magnetic field immunity test . 38
7.3.10 Voltage dips and short interruptions test (AC or DC) . 38
7.3.11 Ripple on DC input power port immunity test . 39
7.3.12 Gradual shutdown / start-up tests . 40
8 Criteria for acceptance . 40
8.1 Emission . 40
8.2 Immunity . 41
9 Test report . 42
(normative) Power frequency immunity tests on binary inputs . 43

A.1 General . 43
A.2 Test classes . 43
A.3 Test equipment . 43
A.3.1 General . 43
A.3.2 Test generator . 43
A.3.3 Verification of the test generator . 44
A.3.4 Coupling networks . 44
A.4 Test set-up . 44
A.4.1 General . 44
A.4.2 Earthing connections . 44
A.4.3 Auxiliary equipment . 44
(informative) Background information for power frequency tests . 47
(informative) Background information about spot frequency tests . 48
(informative) EMC risk assessment . 50
D.1 EMC design risk assessment . 50
D.2 Product platform risk assessment . 52
(informative) Considerations regarding radio interfaces . 54
(informative) Immunity test to be considered in future . 55
Bibliography . 56

Figure 1 – Gradual shutdown / start-up test . 40
Figure A.1 – Example of Zone A differential mode tests . 45
Figure A.2 – Example of Zone B differential mode tests . 45
Figure A.3 – Example of Zone A and Zone B common mode tests . 46

Table 1 – Radiated emission tests – Enclosure port . 14
Table 2 – Required highest frequency for radiated measurement . 15
Table 3 – Conducted emission tests – AC and DC auxiliary power supply port . 15
Table 4 – Conducted emission tests – Wired network port . 15
Table 5 – Immunity tests – Enclosure port . 16
...