IEC TS 62257-9-1:2008

IEC/TS 62257-9-1
Edition 1.0 2008-09
TECHNICAL
SPECIFICATION
Recommendations for small renewable energy and hybrid systems for rural
electrification –
Part 9-1: Micropower systems
IEC/TS 62257-9-1:2008(E)
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IEC/TS 62257-9-1
Edition 1.0 2008-09
TECHNICAL
SPECIFICATION
Recommendations for small renewable energy and hybrid systems for rural
electrification –
Part 9-1: Micropower systems
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
XA
ICS 27.160; 27.180 ISBN 2-8318-9996-6
– 2 – TS 62257-9-1 © IEC:2008(E)
CONTENTS
FOREWORD.5
INTRODUCTION.7
1 Scope.8
2 Normative references .9
3 Terms and definitions .9
4 General .11
4.1 Boundary of a micropower plant .11
4.2 Composition of a micropower plant.12
4.3 General functional layout of a micropower plant .12
5 Design.13
5.1 Design criteria .13
5.2 Power generation mix.14
5.2.1 General .14
5.2.2 Internal combustion generator sets.15
5.3 Electrical design.15
5.3.1 System voltage selection .15
5.3.2 Interconnection of generators .15
5.4 Mechanical and civil works .16
5.4.1 Civil works.16
5.4.2 Technical room.16
5.4.3 Battery room.17
5.4.4 Specific requirements .17
6 Safety issues.17
6.1 Electrical issues .17
6.1.1 General .17
6.1.2 Specific requirements .17
6.2 Mechanical issues .21
6.3 Thermal and fire issues .22
6.4 Noise issues.22
6.5 Access security .22
7 Erection of equipment.22
7.1 Siting.22
7.1.1 Photovoltaic array.22
7.1.2 Wind turbine .23
7.1.3 Micro-hydro turbine .23
7.1.4 Generator set .23
7.1.5 Technical room.23
7.2 Equipment installation .24
7.2.1 Mechanical .24
7.2.2 Electrical .24
8 Acceptance process .26
8.1 General .26
8.2 Phase 1: Preparation.27
8.3 Phase 2: Documentation .27
8.4 Phase 3: Commissioning .27

TS 62257-9-1 © IEC:2008(E) – 3 –
8.4.1 Step 1: Evaluation of the conformity of the installed system with the
accepted design .27
8.4.2 Step 2: Evaluation of qualification of the installation .27
8.4.3 Step 3: Preliminary tests.27
8.4.4 Step 4: Performance testing .28
8.5 Phase 4: Agreement.28
8.6 Commissioning records .28
9 Operation, maintenance and replacement.28
10 Marking and documentation.29
10.1 Marking .29
10.1.1 Information for emergency services .29
10.1.2 Information for maintenance .29
10.1.3 Information for batteries .29
10.1.4 Information for sockets .29
10.1.5 Signs .29
10.2 Documentation .30
Annex A (informative) Selectivity of protection .31
Annex B (informative) Risk assessment of lightning stroke.32
Annex C (normative) Voltage domains .35
Annex D (informative) Battery room .36
Annex E (informative) Energy fraction calculations .39
Annex F (informative) Noise control .41
Annex G (informative) Commissioning record sheet (examples).43
Bibliography.53

Figure 1 – Micropower system limits .11
Figure 2 – Example of functional layout for a micropower plant supplying a.c. energy.13
Figure 3 – Interconnection configuration with d.c. bus and a.c. bus.16
Figure 4 – Interconnection configuration with a.c. bus only .16
Figure 5 – Example of protection against effects of lightning and over-voltage for
generators with two live conductors output (d.c. or a.c.) TNS P+N .18
Figure 6 – Example of protection against effects of lightning over-voltage for three
phase generators with four live a.c. conductors (TNS P+N scheme) – Generator side.19
Figure 7 – Example of a simplified lightning protection including a crow’s foot earth
termination.20
Figure 8 – Protection of a photovoltaic array.21
Figure 9 – Wiring arrangement for equipotential link .21
Figure A.1 – Example of the selectivity of protection .31

Table 1 – Minimum dimensions for lightning protection wires .20
Table 2 – Cross-section of 230 V a.c. power cables .24
Table 3 – Fuse ratings for protection from short-circuiting in 230 V/400 V a.c. circuits .25
Table 4 – Fuse ratings for protection from short-circuiting in 120 V/208 V a.c. circuits .26
Table 5 – Circuit-breaker ratings for protection from short-circuiting .26
Table B.1 – Stake index values.32
Table B.2 – Construction index values .33

– 4 – TS 62257-9-1 © IEC:2008(E)
Table B.3 – Height index values.33
Table B.4 – Situation index values .33
Table B.5 – Lightning prevalence index values .33
Table B.6 – Assessment of risk and need for protection.34
Table C.1 – Voltage domains .35

TS 62257-9-1 © IEC:2008(E) – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY AND
HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-1: Micropower systems
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization compr
...