IEC 62310-3:2008

IEC 62310-3
Edition 1.0 2008-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Static transfer systems (STS) –
Part 3: Method for specifying performance and test requirements

Systèmes de transfert statique (STS) –
Partie 3: Méthode de spécification des performances et exigences d’essai

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IEC 62310-3
Edition 1.0 2008-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Static transfer systems (STS) –
Part 3: Method for specifying performance and test requirements

Systèmes de transfert statique (STS) –
Partie 3: Méthode de spécification des performances et exigences d’essai

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XA
CODE PRIX
ICS 29.200; 29.240.30 ISBN 2-8318-9812-9

– 2 – 62310-3 © IEC:2008
CONTENTS
FOREWORD.4
1 Scope.6
2 Normative references .6
3 Terms and definitions .7
3.1 General definitions .7
3.2 Specified values .10
3.3 Input values.11
3.4 Output values.11
4 Performance requirements .12
4.1 Declared electrical characteristics .12
4.1.1 Performance classification.12
4.1.2 Main electrical characteristics.13
4.2 Normal service conditions .14
4.3 Transfer characteristics .14
4.3.1 Load voltage.14
4.3.2 Cross-current .15
4.4 Neutral management .15
4.4.1 Common neutral .15
4.4.2 Separately derived neutrals .15
4.4.3 Neutral current .15
4.4.4 Protective earth current .15
4.5 Performance requirements to be identified by the purchaser .16
5 STS tests .16
5.1 General .16
5.1.1 Type tests .16
5.1.2 Routine tests .16
5.1.3 Site tests .16
5.1.4 Testing schedule .16
5.2 Electrical tests.18
5.2.1 Insulation and dielectric.18
5.2.2 Light load and functional test.18
5.2.3 No load.19
5.2.4 Rated load.19
5.2.5 Transfer.19
5.2.6 Source tolerance .21
5.2.7 Overload and fault current .21
5.2.8 Operating losses .23
5.2.9 Backfeed .24
5.2.10 Abnormal operating conditions .25
5.3 Transportation and environment .26
5.3.1 General .26
5.3.2 Impact and shock .26
5.3.3 Free fall.26
5.3.4 Storage .27
5.3.5 Temperature and humidity .28
5.3.6 Acoustic noise .28

62310-3 © IEC:2008 – 3 –
Annex A (normative) Reference load.29
Annex B (normative) STS voltage sensing tolerance .33
Annex C (informative) Neutral management in static transfer systems .35
Annex D (normative) Neutral switching in static transfer systems – Additional
requirements.37
Annex E (informative) Purchaser specification guidelines .39
Annex F (informative) Output short circuit test procedure.43
Annex G (normative) Backfeed protection test .47
Annex H (normative) Minimum and maximum cross-sections of copper conductors
suitable for connection.48
Bibliography.49

Figure 1 – Complying load current flow - Common grounding of a.c. input sources -
common STS neutral .15
Figure 2 – Objectionable load current flow - Independent grounding of a.c. input
sources - common STS neutral .16
Figure 3 – STS cross current test.20
Figure 4 – Typical circuit for measuring conduction losses.24
Figure B.1 – Source tolerance classification 1.33
Figure B.2 – Source tolerance classification 2.34
Figure B.3 – Source tolerance classification 3.34
Figure B.4 – Source tolerance classification 4.34
Figure C.1 – Continuous STS neutral with common grounding of a.c. input sources
(complying load current flow) .35
Figure C.2 – Continuous STS neutral with independent grounding of a.c. input sources
+ isolation transformer (complying load current flow) .36
Figure C.3 – Switched STS with independent grounding of a.c. input sources
(complying steady state load current flow) .36
Figure D.1 – Load voltage variation upon neutral switch failure.37
Figure D.2 – Overlapping switched STS neutral .38
Figure F.1 – Test circuit for STS output withstand current.45

Table 1 – Transfer interruption classification “T” .13
Table 2 – Tests for STS performance characteristics .17
Table 3 – Short time withstand current.22
Table 4 – Free fall testing .27
Table E.1 – STS technical data sheet .41
Table F.1 – Values of power-factors and
...