Renewable energy and hybrid systems for rural electrification - Part 9-6: Integrated systems - Recommendations for selection of Photovoltaic Individual Electrification Systems (PV-IES)

IEC TS 62257-9-6:2019 is available as IEC TS 62257-9-6:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 62257-9-6:2019 proposes a simple selection procedure and cheap, comparative tests which can be performed in laboratories of developing countries, in order to identify the most suitable model of small Photovoltaic Individual Electrification Systems (PV- IES) up to 500 Wp for a particular rural electrification project from a number of products submitted for test. The tests provided in IEC TS 62257-9-6 allow assessment of the performance of a PV-IES according to the requirement of the general specification of the project (see IEC/TS 62257-2) and to verify their ability to provide the required service. This second edition of IEC TS 62257-9-6 cancels and replaces the first edition published in 2008. The main technical changes with respect to the previous edition are as follows:
- Removal of the term "small" from the title of the publication and from description of rural electrification systems.
- Removal of the limits on system voltage and power; these recommendations apply to systems of all sizes.

General Information

Status
Published
Publication Date
25-Sep-2019
Current Stage
PPUB - Publication issued
Completion Date
26-Sep-2019
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IEC TS 62257-9-6:2019 - Renewable energy and hybrid systems for rural electrification - Part 9-6: Integrated systems - Recommendations for selection of Photovoltaic Individual Electrification Systems (PV-IES)
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IEC TS 62257-9-6
Edition 2.0 2019-09
TECHNICAL
SPECIFICATION
colour
inside
Renewable energy and hybrid systems for rural electrification –
Part 9-6: Integrated systems – Recommendations for selection of Photovoltaic
Individual Electrification Systems (PV-IES)
IEC TS 62257-9-6:2019-09(en)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC TS 62257-9-6
Edition 2.0 2019-09
TECHNICAL
SPECIFICATION
colour
inside
Renewable energy and hybrid systems for rural electrification –
Part 9-6: Integrated systems – Recommendations for selection of Photovoltaic
Individual Electrification Systems (PV-IES)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160; 27.180 ISBN 978-2-8322-7353-1

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TS 62257-9-6:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms, definitions and abbreviated terms ........................................................................ 8

3.1 Terms and definitions .............................................................................................. 8

3.2 Abbreviated terms ................................................................................................... 9

4 System boundaries .......................................................................................................... 9

5 System pre-selection ....................................................................................................... 9

5.1 Services to be provided by the system .................................................................... 9

5.2 Specification of a model .......................................................................................... 9

5.2.1 General operating conditions ........................................................................... 9

5.2.2 Design ............................................................................................................. 9

5.2.3 Components requirements ............................................................................. 10

5.2.4 Safety issues ................................................................................................. 10

5.2.5 Installation rules ............................................................................................ 10

5.2.6 Operation and maintenance rules .................................................................. 10

5.2.7 Documentation and marking .......................................................................... 10

5.3 Pre-selection process ........................................................................................... 11

5.3.1 Elements of the GS to be provided to potential suppliers ............................... 11

5.3.2 Answers to be provided by potential suppliers ............................................... 11

5.3.3 Pre-selection criteria ...................................................................................... 11

6 Comparative tests .......................................................................................................... 11

6.1 General ................................................................................................................. 11

6.2 Service requirements ............................................................................................ 12

6.3 Service quality index ............................................................................................. 12

6.4 Testing programme ............................................................................................... 15

6.4.1 General ......................................................................................................... 15

6.4.2 Test 1: initial inspection and commissioning .................................................. 16

6.4.3 Test 2: ability to provide the required service under daylight favourable

conditions ...................................................................................................... 17

6.4.4 Test 3: ability to provide the required service under daylight

unfavourable conditions ................................................................................. 20

6.4.5 Test 4: final inspection ................................................................................... 22

6.4.6 General conclusion ........................................................................................ 22

Annex A (informative) Data record sheet for visual inspection .............................................. 24

Annex B (informative) Commissioning records sheet ............................................................ 25

Annex C (informative) Examples of load profiles for comparative tests ................................. 26

C.1 Examples of loads................................................................................................. 26

C.2 Examples of systems ............................................................................................ 26

C.3 Examples of load profiles ...................................................................................... 27

Annex D (informative) Instruction and data record sheet models (according to a load

profile as proposed in Annex A) ............................................................................................ 28

Bibliography .......................................................................................................................... 35

---------------------- Page: 4 ----------------------
IEC TS 62257-9-6:2019 © IEC 2019 – 3 –

Figure 1 – Test 2, Phase A: initial charge cycles ................................................................... 18

Figure 2 – Test 2, Phase B: operating cycles ........................................................................ 19

Figure 3 – Test 3, operating cycles ....................................................................................... 21

Table 1 – Climatic conditions (example) .................................................................................. 9

Table 2 – Suggested minimum values for IP and IK .............................................................. 10

Table 3 – Lighting service indexes ........................................................................................ 13

Table 4 – Radio / TV service indexes .................................................................................... 14

Table 5 – Refrigeration service indexes ................................................................................ 14

Table 6 – Testing programme ............................................................................................... 16

Table A.1 – Data record sheet for visual inspection (example) .............................................. 24

Table B.1 – Commissioning records sheet (example) ............................................................ 25

Table C.1 – Example of loads ............................................................................................... 26

Table C.2– Example of small PV-IES loads (~50 Wp) ........................................................... 26

Table C.3 – Example of medium PV-IES loads (~200 Wp) .................................................... 26

Table C.4 – Example of large PV-IES loads (~500 Wp) ......................................................... 27

Table C.5 – Example of system load profile to perform test on PV-IES .................................. 27

Table D.1 – Overview instruction sheet for daily records (example) ...................................... 28

Table D.2 – Record sheet for lighting service (example) ....................................................... 30

Table D.3 – Record sheet for radio service (example) ........................................................... 31

Table D.4 – Record sheet for TV service (example) .............................................................. 32

Table D.5 – Record sheet for refrigeration service (example) ................................................ 33

Table D.6 – System daily quality index of service evaluation (example) ................................ 34

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– 4 – IEC TS 62257-9-6:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RENEWABLE ENERGY AND HYBRID SYSTEMS
FOR RURAL ELECTRIFICATION –
Part 9-6: Integrated systems – Recommendations for selection
of Photovoltaic Individual Electrification Systems (PV-IES)
FOREWORD

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Technical specifications are subject to review within three years of publication to decide

whether they can be transformed into International Standards.

IEC 62257-9-6, which is a technical specification, has been prepared by IEC technical

committee 82: Solar photovoltaic energy systems.
---------------------- Page: 6 ----------------------
IEC TS 62257-9-6:2019 © IEC 2019 – 5 –

This second edition of IEC TS 62257-9-6 cancels and replaces the first edition published in

2008. It constitutes a technical revision.
The main technical changes with respect to the previous edition are as follows:

• Removal of the term "small" from the title of the publication and from description of rural

electrification systems.

• Removal of the limits on system voltage and power; these recommendations apply to

systems of all sizes.
This part of IEC 62257 is to be used in conjunction with the IEC 62257 series.
The text of this technical specification is based on the following documents:
Enquiry draft Report on voting
82/1279/DTS 82/1533A/RVDTS

Full information on the voting for the approval of this technical specification can be found in

the report on voting indicated in the above table.

This document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of IEC 62257 series, under the general title: Renewable energy and hybrid

systems for rural electrification, can be found on the IEC website.

Future standards in this series will carry the new general title as cited above. Titles of existing

standards in this series will be updated at the time of the next edition.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 7 ----------------------
– 6 – IEC TS 62257-9-6:2019 © IEC 2019
INTRODUCTION

The IEC 62257 series intends to provide different players involved in rural electrification

projects (such as project implementers, project contractors, project supervisors, installers,

product suppliers, etc.) documents for setting up renewable energy and hybrid systems with

a.c. voltage below 1 000 V and d.c. voltage below 1 500 V.
These documents are recommendations:
• to choose the right system for the right place;
• to design the system;
• to ensure product quality and installation quality;
• to operate and maintain the system.

These documents are focused on off-grid electricity access, concentrating on, but not limited

to, areas with a significant fraction of the population living without reliable electric grid access.

They should not be considered as providing complete coverage of all issues related to rural

electrification.

This set of documents is best considered as a whole, with different parts covering topics such

as safety, system design, product quality, installation and maintenance, and the sustainability

of systems aiming at the lowest life cycle cost possible. One of the main objectives is to

provide minimum requirements relevant to renewable energy and hybrid off-grid power

systems.
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IEC TS 62257-9-6:2019 © IEC 2019 – 7 –
RENEWABLE ENERGY AND HYBRID SYSTEMS
FOR RURAL ELECTRIFICATION –
Part 9-6: Integrated systems – Recommendations for selection
of Photovoltaic Individual Electrification Systems (PV-IES)
1 Scope

The purpose of this part of IEC 62257 is to propose simple selection procedure and cheap,

comparative tests which can be performed in laboratories of developing countries, in order to

identify the most suitable model of Photovoltaic Individual Electrification Systems (PV-IES) up

to 500 Wp for a particular rural electrification project from a number of products submitted for

test.

It is different from the scope of IEC 62124, Photovoltaic (PV) stand alone systems – Design

verification, which provides guidance for verifying the design of stand-alone PV systems and

indoor and outdoor tests in order to evaluate the performance of PV systems including PV

generator, battery storage and loads such as lights, TV sets, and refrigerators.

The tests provided in this document allow assessment of the performance of PV-IES

according to the requirement of the General Specification (GS) of the project (see

IEC TS 62257-2) and to verify their ability to provide the required service. They are performed

locally, as close as possible to the real site operating conditions.

This document is not a type approval standard. It is a technical specification to be used as

guidelines and does not replace any existing IEC standard on PV systems.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements 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 61215 (all parts), Crystalline silicon terrestrial photovoltaic (PV) modules – Design

qualification and type approval

IEC 61730-1, Photovoltaic (PV) module safety qualification – Part 1: Requirements for

construction

IEC 61730-2, Photovoltaic (PV) module safety qualification – Part 2: Requirements for testing

IEC TS 62257-2:2015, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 2: From requirements to a range of electrification systems

IEC TS 62257-4, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 4: System selection and design

IEC TS 62257-5, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 5: Protection against electrical hazards

IEC TS 62257-6, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 6: Acceptance, operation, maintenance and replacement
---------------------- Page: 9 ----------------------
– 8 – IEC TS 62257-9-6:2019 © IEC 2019

IEC TS 62257-7-1, Recommendations for small renewable energy and hybrid systems for

rural electrification – Part 7-1: Generators – Photovoltaic generators

IEC TS 62257-8-1:2018, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 8-1: Selection of batteries and battery management systems for stand-alone

electrification systems – Specific case of automotive flooded lead-acid batteries available in

developing countries

IEC TS 62257-9-3, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 9-3: Integrated system – User interface

IEC TS 62257-9-4, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 9-4: Integrated system – User installation

IEC TS 62257-12-1, Recommendations for renewable energy and hybrid systems for rural

electrification – Part 12-1: Selection of lamps and lighting appliances for off-grid electricity

systems
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
cycle

sequence of a discharge followed by a charge or a charge followed by a discharge of a

battery under specified conditions
3.1.2
duration of service
number of hours when a load is powered
3.1.3
fulfilment of service
ratio of a measured provided service to a required service
3.1.4
initial charge

commissioning charge given to a new battery to bring it to the fully charged state

3.1.5
period of service
part of the day when a load is powered
3.1.6
reference irradiation

value of irradiation taken in consideration for the design of the system, approved by the

project implementer and specified in the GS of the project
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IEC TS 62257-9-6:2019 © IEC 2019 – 9 –
3.1.7
service ratio
extent in which the service required by the GS is fulfilled by the system
3.2 Abbreviated terms
GS general specification for the project
QI quality of service index
TWQI total weighted quality of service
DWQI daily weighted quality of service
S service ratio under favourable conditions
good
S service ratio under unfavourable conditions
bad
S daily service ratio
4 System boundaries
A PV-IES comprises the following elements:
• a PV generator including PV modules and support structure;
• a charge controller;
• a storage system (including battery and associated casing);
• adequate wiring, switches and protective devices (see IEC TS 62257-9-3 and
IEC TS 62257-9-4);

• loads relevant for the required service (such as lamps, TV set, radio set, and refrigerators).

5 System pre-selection
5.1 Services to be provided by the system

The preliminary socio-economic studies shall provide the project developer with information

on the ability of the customers who will benefit from the project to pay for the service provided.

Then, the project developer shall define within the GS the range of services to be provided as

described in IEC TS 62257-2 as well as the relative priority of the services to be provided (TV,

lighting, etc.)
5.2 Specification of a model
5.2.1 General operating conditions

The project implementer shall define the operating conditions to which the PV-IES can be

subjected. Examples of such conditions are given in Table 1.
Table 1 – Climatic conditions (example)
Nominal operating range Storage – Transport
Temperature –10 °C to +50 °C –40 °C to +80 °C
Humidity at 28 °C 5 % to 95 %
Atmospheric pressure 860 hPa to 1 060 hPa
5.2.2 Design

For the part of the project which will be implemented through Individual Electrification

Systems, the project developer shall size a range of PV IES able to provide the required

---------------------- Page: 11 ----------------------
– 10 – IEC TS 62257-9-6:2019 © IEC 2019

service under the specified operating conditions (see IEC TS 62257-2). The project

implementer could either:
• specify complete integrated systems, or

• specify the different components for PV-IES in order to realize the integration of these

components through its own system design.

In addition, the project developer shall set up the requirements for the loads relevant for the

service to be provided (such as lamps, TV set, radio set, and refrigerator).
5.2.3 Components requirements

The components of the PV-IES shall comply with the relevant IEC standards and/or the

relevant local regulations if any.

For the selection of batteries, tests recommended in IEC TS 62257-8-1 shall apply and for the

selection of lamps, tests recommended in IEC TS 62257-12-1 shall apply.
5.2.4 Safety issues

The project developer shall define the IP degree and IK code of the expected products.

Table 2 gives some values that could be considered as a minimum.
Table 2 – Suggested minimum values for IP and IK
Protection degree Minimum suggested value
IP 34
IK 8
Safety rules shall comply with IEC TS 62257-5.
5.2.5 Installation rules

The complete installation shall comply with IEC TS 62257-7-1 and IEC TS 62257-9-4 and any

local wiring codes.
5.2.6 Operation and maintenance rules

The systems shall be designed in order that operation and maintenance may be performed in

accordance with the specifications given in IEC TS 62257-6.
5.2.7 Documentation and marking

A manual shall also be provided including PV-IES installation and operating guidelines such

as:
• initial operations before first use;
• instructions to use the PV-IES properly;
• mounting the PV module;
• charging instructions;
• maintenance and troubleshooting instructions.
---------------------- Page: 12 ----------------------
IEC TS 62257-9-6:2019 © IEC 2019 – 11 –
5.3 Pre-selection process
5.3.1 Elements of the GS to be provided to potential suppliers

The project implementer shall supply the annual locally available solar irradiation curve.

NOTE This information could be provided through available laboratory data or through local measurements

performed with a reference cell that will be used afterwards for the comparative tests.

This information as well as the requirements defined in 5.1 and 5.2 shall be provided to

potential suppliers in order to receive proposals for relevant products.
The project implementer could:

• provide load requirements and let the suppliers provide systems to supply the load, or

• provide a complete PV-IES system specification, in order to source complete integrated

PV-IES, or

• provide components requirements in order to source separately the different components

of a PV-IES and realize the integration of these components.
5.3.2 Answers to be provided by potential suppliers

The supplier of the PV-IES and/or of the components shall prove that the PV-IES and/or the

components comply with the relevant IEC standards and IEC 62257 technical specifications.

A technical sheet shall be provided by the supplier in order to demonstrate the ability of its

product to match the requirements defined in 5.1 and 5.2.
5.3.3 Pre-selection criteria

The performances claimed by the manufacturer shall be compared to the performances

required by the GS in order to make a pre-selection of available products.

The following general criteria can be used as an initial help for product pre-selection:

• services characteristics claimed by the manufacturer (duration of service and fulfillment of

service);

• conformity of the modules with the following IEC standards: IEC 61215 series and

IEC 61730-1 and IEC 61730-2;
• conformity of the batteries, lamps, etc., with
...

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