SIST-TS IEC/TS 62257-9-6:2009

• Abstract:

  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 small Photovoltaic Individual Electrification Systems (PVIES) up to 500 Wp for a particular rural electrification project from a number of products submitted for test. It is different of 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 IEC 62257-9-6 allow assessment of the performance of a 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 should be 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.

• Status: Published
• Public Enquiry End Date: 31-Dec-2008
• Publication Date: 11-Jan-2009
• ICS: 27.160 - Solar energy engineering
• ICS: 27.190 - Biological sources and alternative sources of energy
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 09-Jan-2009
• Due Date: 16-Mar-2009
• Completion Date: 12-Jan-2009
• Ref Project: IEC/TS 62257-9-6 - Recommendations for small renewable energy and hybrid systems for rural electrification - Part 9-6: Integrated system - Selection of Photovoltaic Individual Electrification Systems (PV-IES)

SIST-TS IEC/TS 62257-9-6:2009 is the Slovenian adoption of IEC/TS 62257-9-6, published by the International Electrotechnical Commission (IEC). It gives a selection procedure and comparative test method for small Photovoltaic Individual Electrification Systems (PV-IES) up to 500 Wp used in rural electrification projects. The document is intended for project developers, laboratories, and suppliers who need to check whether a PV-IES can deliver the services defined in a project’s General Specification (GS).

What does SIST-TS IEC/TS 62257-9-6:2009 specify?

SIST-TS IEC/TS 62257-9-6:2009 specifies how to pre-select and compare PV-IES products for a rural electrification project. It focuses on practical selection and local testing, not on type approval or replacing other IEC standards.

The scope is narrow and practical: the document proposes a simple selection procedure and inexpensive comparative tests that can be carried out in laboratories in developing countries, or as close as possible to real site conditions. It is meant to assess whether a small PV-IES can provide the services required by the project GS.

The document is organized into six clauses and four informative annexes:

Annex	What it covers
Annex A	Data record sheet for visual inspection
Annex B	Commissioning records sheet
Annex C	Examples of load profiles for comparative tests
Annex D	Instruction and data record sheet models

Clause 1 gives the scope, Clause 2 lists the normative references, Clause 3 defines the main terms and abbreviations, Clause 4 sets the system boundaries, Clause 5 covers system pre-selection, and Clause 6 defines the comparative tests and pass or fail logic.

What are the key requirements of SIST-TS IEC/TS 62257-9-6:2009?

SIST-TS IEC/TS 62257-9-6:2009 ties selection to the project GS, then tests candidate systems under controlled local conditions. In practice, this means the project team must define the needed services first, then compare products against those needs rather than against a generic product class.

Define the system and the project needs

Clause 4 defines a PV-IES as including the PV generator, charge controller, storage system, wiring, switches, protective devices, and the loads needed for the service. Clause 5.1 requires the project developer to define the service range and the relative priority of those services in the GS.

This matters because the tests are service-based, not just hardware-based. A system is judged by whether it can supply lighting, radio, TV, refrigeration, or other defined loads for the required time and quality.

Pre-select products before testing

Clause 5.2 requires the project implementer to define operating conditions, design the required range of systems, and specify load requirements. The document also requires the relevant component standards and local regulations to be considered, and it links battery selection to IEC/TS 62257-8-1 and lamp selection to IEC/TS 62257-12-1.

For safety and installation, Clause 5.2 points to the expected IP degree and IK code, and it links safety rules to IEC/TS 62257-5. It also requires installation to comply with IEC/TS 62257-7-1, IEC/TS 62257-9-4, and local wiring codes, while operation and maintenance must follow IEC/TS 62257-6.

Prepare the supplier information and shortlist

Clause 5.3 requires the project implementer to provide the annual locally available solar irradiation curve and the service requirements to potential suppliers. Suppliers must show conformity with the relevant IEC standards and technical specifications, and provide a technical sheet showing how the product meets the GS.

The practical result is a shortlist of products that appear capable of meeting the project need before any test campaign starts. That keeps the comparative testing focused on realistic candidates.

Use the comparative test sequence

Clause 6 sets out four tests: initial inspection and commissioning, service under daylight favourable conditions, service under daylight unfavourable conditions, and final inspection. The complete test set is intended to be carried out over a period of 90 days during the appropriate season.

The document requires the pre-selected systems to be tested simultaneously under the same local conditions. That is important because irradiation, temperature, and humidity can strongly affect PV performance.

Measure service quality with QI, DWQI, TWQI, and service ratio

Clause 6.3 introduces the quality of service index (QI), the daily weighted quality of service index (DWQI), the total weighted quality of service index (TWQI), and the service ratio S. For lighting and refrigeration, the document uses fulfilment-based checks; for radio and TV, it uses duration-based checks.

This matters because the method compares products on the service actually delivered, not only on nominal electrical ratings. It lets the project team weight lighting, radio, TV, and refrigeration according to the GS.

Apply the pass and fail thresholds

Clause 6.4.3 sets the pass criterion for daylight favourable conditions at S ≥ 0.70. Clause 6.4.4 sets the pass criterion for daylight unfavourable conditions at S ≥ 0.35.

Clause 6.4.2 and Clause 6.4.5 use visual inspection before and after the test period to check for defects and deterioration. The final conclusion in Clause 6.4.6 accepts only the models whose three samples pass all four tests.

Select among accepted models

Clause 6.4.6 also says the project implementer should compare accepted models using annual irradiation weighting and economic considerations. In practice, this is the step where technical performance is balanced with project cost and the expected local solar pattern.

What terms does SIST-TS IEC/TS 62257-9-6:2009 define?

• Cycle - A sequence of discharge followed by charge, or charge followed by discharge, for a battery under specified conditions.
• Duration of service - The number of hours during which a load is powered.
• Fulfilment of service - The ratio between the measured provided service and the required service.
• Initial charge - The commissioning charge given to a new battery so it reaches full charge.
• Reference irradiation - The irradiation value used for system design, approved by the project implementer and stated in the GS.
• Service ratio - The extent to which the service required by the GS is fulfilled by the system.
• GS - General specification for the project.
• QI / TWQI / DWQI - The quality of service index, total weighted quality of service index, and daily weighted quality of service index used to compare systems.

Who uses SIST-TS IEC/TS 62257-9-6:2009?

SIST-TS IEC/TS 62257-9-6:2009 is used by project developers, project implementers, contractors, supervisors, installers, laboratory operators, and suppliers involved in rural electrification projects. It is also useful for buyers and quality managers who need a consistent way to shortlist and compare PV-IES products.

In practice, project developers use it to define the GS and service priorities. Laboratories use it to run the comparative tests, record commissioning data, and evaluate service quality. Suppliers use it to prepare technical sheets and show how their products match the required services and component standards.

What changed in SIST-TS IEC/TS 62257-9-6:2009 from the previous edition?

SIST-TS IEC/TS 62257-9-6:2009 is based on IEC/PAS 62111 (1999) and cancels and replaces the relevant parts of IEC/PAS 62111.

Which standards are used with SIST-TS IEC/TS 62257-9-6:2009?

Reference	What it contributes
IEC 61215	Design qualification and type approval for crystalline silicon terrestrial PV modules
IEC 61646	Design qualification and type approval for thin-film terrestrial PV modules
IEC 61730-1	Construction requirements for PV module safety qualification
IEC 61730-2	Testing requirements for PV module safety qualification
IEC/TS 62257-2	Project requirements and the range of electrification systems
IEC/TS 62257-4	System selection and design
IEC/TS 62257-5	Protection against electrical hazards
IEC/TS 62257-6	Acceptance, operation, maintenance, and replacement
IEC/TS 62257-7-1	Photovoltaic arrays
IEC/TS 62257-8-1	Selection of batteries and battery management systems
IEC/TS 62257-9-3	User interface
IEC/TS 62257-9-4	User installation
IEC/TS 62257-12-1	Selection of self-ballasted lamps for rural electrification systems

These references give the component, safety, installation, and project-planning framework that the PV-IES selection procedure depends on.

What does the SIST-TS IEC/TS 62257-9-6:2009 document contain?

The document contains the selection method, the test sequence, and the recording templates needed to apply the method. Clause 5 provides the pre-selection logic, including what the GS must define and what suppliers must submit.

Clause 6 contains the core test method, including the service quality calculations, the four-test programme, and the acceptance thresholds. The annexes provide practical tools: a visual inspection sheet in Annex A, a commissioning sheet in Annex B, example load profiles in Annex C, and daily instruction and record sheet models in Annex D.

The document also includes figures showing the operating cycles for Test 2 and Test 3, and tables covering climatic conditions, suggested IP and IK values, service indexes for lighting, radio/TV, and refrigeration, and the overall testing programme. In practice, these tables and forms support field or laboratory comparison, documentation, and consistent decision-making.

SLOVENSKI STANDARD
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Recommendations for small renewable energy and hybrid systems for rural electrification
- Part 9-6: Integrated system - Selection of Photovoltaic Individual Electrification Systems
(PV-IES)
Ta slovenski standard je istoveten z: IEC/TS 62257-9-6
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
27.190 Biološki viri in drugi Biological sources and
alternativni viri energije alternative sources of energy
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

Edition 1.0 2008-09
TECHNICAL
SPECIFICATION
Recommendations for small renewable energy and hybrid systems for rural
electrification –
Part 9-6: Integrated system – Selection of Photovoltaic Individual Electrification
Systems (PV-IES)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
W
ICS 27.160; 27.180 ISBN 2-8318-9997-4
– 2 – TS 62257-9-6 © IEC:2008(E)
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.10
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 .11
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 .12
6.1 General .12
6.2 Service requirements .12
6.3 Service quality index .12
6.4 Testing programme .16
6.4.1 General .16
6.4.2 Test 1: initial inspection and commissioning .17
6.4.3 Test 2: ability to provide the required service under daylight
favourable conditions.18
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.23
Annex A (informative) Data record sheet for visual inspection.25
Annex B (informative) Commissioning records sheet.26
Annex C (informative) Examples of load profiles for comparative tests.28
Annex D (informative) Instruction and data record sheet models (according to a load
profile as proposed in Annex A) .30
Bibliography.36

Figure 1 – Test 2, Phase A: initial charge cycles.19
Figure 2 – Test 2, Phase B: operating cycles .20
Figure 3 – Test 3, operating cycles .22

TS 62257-9-6 © IEC:2008(E) – 3 –
Table 1 – Climatic conditions (example).10
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) .25
Table B.1 – Commissioning records sheet (example).26
Table C.1 – Example of loads .28
Table C.2 – Example of small PV-IES loads (~50 Wp) .28
Table C.3 – Example of medium PV-IES loads (~200 Wp) .28
Table C.4 – Example of large PV-IES loads (~500 Wp).29
Table C.5 – Example of system load profile to perform test on PV-IES.29
Table D.1 – Overview instruction sheet for daily records (example) .30
Table D.2 – Record sheet for lighting service (example) .31
Table D.3 – Record sheet for radio service (example).32
Table D.4 – Record sheet for TV service (example) .33
Table D.5 – Record sheet for refrigeration service (example).34
Table D.6 – System daily quality index of service evaluation (example) .35

– 4 – TS 62257-9-6 © IEC:2008(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-6: Integrated system –
Selection of Photovoltaic Individual
Electrification Systems (PV-IES)

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-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
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
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
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.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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.
The main task of IEC technical committees is to prepare International Standards. In
exceptional circumstances, a technical committee may propose the publication of a technical
specification when
• the required support cannot be obtained for the publication of an International Standard,
despite repeated efforts, or
• the subject is still under technical development or where, for any other reason, there is the
future but no immediate possibility of an agreement on an International Standard.
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.

TS 62257-9-6 © IEC:2008(E) – 5 –
This document is based on IEC/PAS 62111 (1999); it cancels and replaces the relevant parts
of IEC/PAS 62111.
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
82/510/DTS 82/532/RVC
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 publication 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: Recommendations for small
renewable energy and hybrid systems for rural electrification, 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
• transformed into an International standard,
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

– 6 – TS 62257-9-6 © IEC:2008(E)
INTRODUCTION
The IEC 62257 series of documents intends to provide to different players involved in rural
electrification projects (such as project implementers, project contractors, project supervisors,
installers, etc.) documents for the setting up of renewable energy and hybrid systems with a.c.
voltage below 500 V, d.c. voltage below 750 V and power below 100 kVA.
These documents are recommendations:
• to choose the right system for the right place;
• to design the system;
• to operate and maintain the system.
These documents are focused only on rural electrification concentrating on but not specific to
developing countries. They must not be considered as all inclusive to rural electrification. The
documents try to promote the use of renewable energies in rural electrification; they do not
deal with clean mechanisms developments at this time (CO emission, carbon credit, etc.).
Further developments in this field could be introduced in future steps.
This consistent set of documents is best considered as a whole with different parts
corresponding to items for safety, sustainability of systems and at the lowest life cycle cost as
possible. One of the main objectives is to provide the minimum sufficient requirements,
relevant to the field of application that is: small renewable energy and hybrid off-grid systems.
This document and the others of the IEC 62257 series are only guidance and so cannot be
International Standards. Additionally their subject is still under technical development and so
they shall be published as Technical Specifications.

TS 62257-9-6 © IEC:2008(E) – 7 –
RECOMMENDATIONS FOR SMALL RENEWABLE ENERGY
AND HYBRID SYSTEMS FOR RURAL ELECTRIFICATION –

Part 9-6: Integrated system –
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 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.
It is different of 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 IEC 62257-9-6 allow assessment of the performance of a 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 should be 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 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 61215, Crystalline silicon terrestrial photovoltaic (PV) modules – Design qualification and
type approval
IEC 61646, Thin-film 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 62257-2:2004, Recommendations for small renewable energy and hybrid systems for
rural electrification – Part 2: From requirements to a range of electrification systems
IEC/TS 62257-4, Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 4: System selection and design

– 8 – TS 62257-9-6 © IEC:2008(E)
IEC/TS 62257-5, Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 5: Protection against electrical hazards
IEC/TS 62257-6, Recommendations for small renewable energy and hybrid systems for rural
electrification – Part 6: Acceptance, operation, maintenance and replacement
IEC/TS 62257-7-1, Recommendations for small renewable energy and hybrid systems for
rural electrification – Part 7-1: Generators – Photovoltaic arrays
IEC/TS 62257-8-1:2007, Recommendations for small 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 small renewable energy and hybrid systems for
rural electrification – Part 9-3: Integrated system – User interface
IEC/TS 62257-9-4, Recommendations for small renewable energy and hybrid systems for
rural electrification – Part 9-4: Integrated system – User installation
IEC/TS 62257-12-1, Recommendations for small renewable energy and hybrid systems for
rural electrification – Part 12-1: Selection of self-ballasted lamps (CFL) for rural electrification
systems and recommendations for household lighting equipment
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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

TS 62257-9-6 © IEC:2008(E) – 9 –
3.1.7
service ratio
extent in which the service required by the GS is fulfilled by the system
3.2 Abbreviated terms
3.2.1
GS
general specification for the project
3.2.2
QI
quality of service index
3.2.3
TWQI
T
total weighted quality of service
3.2.4
DWQI
T
daily weighted quality of service
3.2.5
S , S and S
good bad d
S : service ratio under favourable conditions;
good
S : service ratio under unfavourable conditions;
bad
S : daily service ratio
d
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.

– 10 – TS 62257-9-6 © IEC:2008(E)
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
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.

TS 62257-9-6 © IEC:2008(E) – 11 –
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.
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, IEC 61646,
IEC 61730-1 and IEC 61730-2;
• conformity of the batteries, lamps, etc. with the relevant IEC standards and pre-selection
process of potential products as recommended in the IEC/TS 62257 series;
• battery casing characteristics.
A short list of products potentially able to match the requirements of the GS shall be set up by
the project implementer.
– 12 – TS 62257-9-6 © IEC:2008(E)
6 Comparative tests
6.1 General
After the pre-selection process, samples of products of the short list shall be processed
through comparative technical tests.
IMPORTANT: All the pre-selected systems shall be tested simultaneously in the same local
conditions in order to ensure that they are tested under the same environmental parameters
(irradiation, humidity, temperature, etc.).
Tests could be performed either in outdoor conditions, in local laboratories or in site
conditions (on future customer homes for instance). The systems installation rules provided in
the GS are also applicable to test installations.
6.2 Service requirements
Pre-selected models shall be examined to ensure that they will provide the required services
mentioned in the GS according to the load profile used for the design of the system.
A service is defined by:
• The types of appliances/loads powered by the system (such as lamps, TV set, etc.);
• For each type of appliance:
– the number of appliances that can be simultaneously powered;
– the daily duration of the power supply;
– the fulfilment of the provided service.
6.3 Service quality index
A Quality of service Index (QI) of a system is based on one of these two terms:
• d = duration index, d, is the ratio of the measured daily duration of service compared to
the required daily duration of service;
• f = fulfilment index, f, is the ratio of the measured performance (illuminance for lamps,
temperature for refrigerator, etc.) compared to a reference level required by the GS.
For the different considered services the QI takes into account either, d, or, f:
– for lighting: f;
– for radio: d;
– for TV: d;
– for refrigeration: f.
The systems shall be compared through a Total Weighted Quality of service Index (TWQI )
T
calculated on the basis of observations and measurements performed during, T, days of
comparative tests.
The TWQI and service ratio (S) are calculated as follows:
T
Step 1: for each service, calculation every day of either “duration” or “fulfilment”
indexes
The following tables illustrate the necessary index evaluation data and calculation rules.

TS 62257-9-6 © IEC:2008(E) – 13 –
Table 3 – Lighting service indexes
Service Lighting
Requirements Number of lamps  N

L
Daily duration of service per lamp (h) D

L
Illuminance (lux)  Q
Duration index Fulfilment index
Measured Total measured Fulfilment index
illuminance illuminance for
every hour of
service
lux lux
see Note 1 see Note 2
Not relevant
For lamp 1:
q
L1
j =D
i=n
i =n L
For lamp 2:
q
L
∑∑
q q i
∑ L
L2
i
j=11i =
f =
i =1
Lighting
…
n ×Q
For lamp i:
q
Li
NOTE 1 n = number of illuminance measurements at each hour of service; n ≤ N
;
L
NOTE 2 In order to limit the number of measurements, if N > 3, n could be limited to n = 3
L
j=D
i =3
L
q
L
∑∑
i
j =1 i =1
In this case the formula becomes:
f =
Lighting
3 ×Q
In this example only 3 lamps out of N are measured every hour. Generally it is preferable to
L
ensure that all the lamps have been equally monitored at the end of the test.
A complete example for the lighting service is given in Table D.2.

– 14 – TS 62257-9-6 © IEC:2008(E)
Table 4 – Radio / TV service indexes
Service Radio (or TV) (see Note)
Requirements Number of radio sets N

R
Daily duration of service per set (h) D

R
Fulfilment index
Duration index
Total required Measured Total Duration index
daily duration of daily measured
service duration of daily
service duration of
service
Not relevant
h h
i =N
R
i=N
For set 1: R
N × D
d
R R
∑ R
i
d
R
∑
i
i =1
d
d =
R1
i =1 Radio
N × D
R R
NOTE In the TV set case, subscript R should be changed to T.

Table 5 – Refrigeration service indexes
Service Refrigeration
Requirements
Number of refrigerators N (N =1 in most cases)
F F
Daily duration of service (h) Not relevant
Temperature (°C)  Temperature reference: T°
Duration index Fulfilment index
Measured Average Fulfilment index
measured
temperature: Θ
temperature
deviation
°C
°C
measure 1
i =n
⎛ ⎞
Not relevant
Δθ = Θ – T
i =n ⎜ ⎟
1 1
Δθ
∑ i
⎜ ⎟
Δθ
measure 2
∑ i
i =1
f = 1−⎜ ⎟
i =1
Δθ
2 ⎜ n×T ⎟
n
⎜ ⎟
…
⎜ ⎟
⎝ ⎠
measure n
Δθ
n
n = number of temperature measurements

Step 2: for each tested system, calculation of a DWQI
T:
For a given service X, the Quality of service Index (QI) is:
QI = d
X X
or
QI = f
.
X X
TS 62257-9-6 © IEC:2008(E) – 15 –
If the project implementer does not give the same priority to the services, he could determine
some “weighting coefficients”, k, reflecting the relative importance assigned to the different
services provided.
The relative priority of the different services shall be determined by a socio-economic study
(see 5.1).
Using these weighting coefficients, a Daily Weighted Quality Index (DWQI) shall be calculated
for a system, as given in the following formula (1). For a given day, t, and for X types of
services:
i =X
DWQI = k × QI (1)
t
∑ i i
i =1
– For lamps: k = k
Lighting L
– For radios: k = k
Radio R
– For TVs: k = k
TV T
– For refrigerators: k = k
Fridge F
Using this hypothesis, for a system providing all the mentioned services the DWQI for a day, t,
is:
DWQI = (k × QI ) + (k × QI ) + (k × QI ) + (k × QI )
t L Lighting R Radio T TV F Fridge
It is the project developer’s responsibility to determine the k coefficients according to the
importance he gives to each service.
NOTE As an example, a convenient rule to determine values for the weighting coefficient, k, may be based on the
daily required duration of service (see
...