IEC TS 62257-9-6:2008

IEC/TS 62257-9-6
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)
IEC/TS 62257-9-6:2008(E)
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IEC/TS 62257-9-6
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,
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Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
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6) All users should ensure that they have the latest edition of this publication.
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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
To tal 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 Table D.6).
Step 3: for each tested system, calculation of a TWQI :
T
On the complete duration of the test, a TWQI shall be determined according to the following
T
formula (2). For a test performed on, T, days:
t =T
TWQI = DWQI (2)
t
T ∑
t =0
i =X
with TWQI = T × k (case where all service quality indexes are equal to 1)
T,max
∑ i
i =1
– 16 – TS 62257-9-6 © IEC:2008(E)

Step 4: for each tested system, calculation of a service ratio, S

The laboratory operator shall calculate the maximum value of the TWQI in the conditions of

T
the test.
Then he shall calculate for each system the service ratio by the following formula (3):

TWQI
T,act
(3)
S =
TWQI
T,max
where
TWQI : results of TWQI
T,act T;
and TWQI : maximum value of TWQI
T,max T
This ratio expresses to what extent the system is able to provide the service required by the
GS.
6.4 Testing programme
6.4.1 General
The comparative tests include a set of 4 tests as indicated in Table 6.
The complete set of tests is intended to be performed within a period of 90 days during the
appropriate season as identified during the project preliminary studies and according to the
quality of service specified by the project developer (see IEC/TS 62257-2, Annex C).
The system shall be tested under two daylight conditions:
– Daylight favourable conditions: in this configuration local irradiation is at least 90 % of the
reference value given in the GS.
– Daylight unfavourable conditions: in this configuration, the irradiation taken in account
shall be determined by the project implementer as a percentage of the reference value
given in the GS (such as for example the irradiation during the rainy season).
Table 6 – Testing programme
Test 1: Test 2: Test 3: Test 4:
Initial inspection and Ability to provide Ability to recover the Final inspection
commissioning the required required service

service under  under daylight

daylight Unfavourable
Favourable conditions
conditions
See 6.4.2 See 6.4.3 See 6.4.4 See 6.4.5

TS 62257-9-6 © IEC:2008(E) – 17 –

6.4.2 Test 1: initial inspection and commissioning

6.4.2.1 General
The purpose of the different inspection tests (Test 1 and Test 4) is to assess the evolution /
degradation of the conditions of the different parts of the product during the test period,

especially casings, lamps, cables and PV modules.

The initial inspection is intended to record all necessary details of each sample of each pre-

selected model and identify the sample for the duration of all tests. It will also verify that the

sample has been supplied with all necessary items and components required by the GS.

In Test 1, after the initial inspection, the system shall be commissioned.
As much information as possible concerning each sample to be tested should be recorded.
6.4.2.2 Sampling
Three samples of each model are required. For small projects, if the cost of the testing is too
high, the sampling could be limited to two samples of each model.
A test item number shall be assigned to each sample and used in all data sheets and records
to avoid confusing sample results. It is recommended that the unit should be photographed in
such a way that all major accessible components are recorded.
6.4.2.3 Operation
The initial inspection shall be performed in two steps:
– unpacking step; and
– installation step.
A list (non comprehensive) of items to be checked and recorded during these two periods is
provided as an example in Annex A.
After the initial inspection and installation of the system, commissioning shall be performed
(an example of a commissioning sheet is given in Annex B).
6.4.2.4 Results
The pass criteria is based on the following:

For each sample:
• there shall be no visual evidence of a major defect on any component; and
• the sample is complete; and
• the installed system has been commissioned satisfactorily.
The fail criteria is based on the following:
For each sample:
• there is evidence of a major defect; or
• some components are missing or incorrect; or
• the system cannot be installed properly according to the GS requirements.
It is up to the project implementer to determine whether he will accept a certain model if one
or more samples have failed this initial visual inspection.

– 18 – TS 62257-9-6 © IEC:2008(E)

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

conditions
6.4.3.1 General
The purpose of this test is to check the ability of a PV-IES product to perform the required

service under daylight sunny conditions considered as favorable.

A reference load profile shall be established for the tests according to the service required in

the GS. Some examples of such load profiles are given in Annex C.

6.4.3.2 Sampling
Each model for which the three samples passed Test 1 shall go through to Test 2.
6.4.3.3 Equipment
To perform Test 2 the following equipment shall be necessary:
• A power system to supply energy to all test instruments.
NOTE 1 If the testing is performed in a laboratory connected to a grid, no additional power system is necessary. If
the testing is performed on site, a dedicated power system is necessary to supply energy to testing devices.
• A reference device (such as a reference PV module, pyrheliometer, and so on) to assess
and record the daily irradiation.
NOTE 2 This device may also be initially used to assess the value of the irradiation to be taken in account for the
design of the systems.
• Test instruments:
– Programmable controllers to monitor the load profiles. If not, the loads may be
switched on/off manually.
– One (or several) illuminance measurement box(es) (see IEC/TS 62257-12-1).
– A thermometer, preferably electronic.
6.4.3.4 Operation
Test 2 shall be performed according to the following phases:
6.4.3.4.1 Phase A: initial preparation
This phase is dedicated to charge the battery before testing the ability of the system to
perform the required service.
The initial charge is controlled by the charge controller of the PV-IES without any manual
intervention. During the initial charge, all the loads shall be switched off.
The initial charge shall be performed for, x days (x ≥ 5) until 5 “good sunny days” have been
recorded. A “good sunny day” is defined as a day when irradiation is equal to or greater than
90 % of the reference irradiation defined in the GS (considered as favourable conditions).
The following Figure 1 illustrates the Phase A cycles:

TS 62257-9-6 © IEC:2008(E) – 19 –

START Test 2,
Phase A
t = 0
Sunrise
Charge battery
under daylight
without any load
t = x days
STOP Test 2,
Phase A
Repeat x days the cycle (until 5 “good sunny days”)

Wait until next
morning without
any load
Sunset
IEC  1541/08
NOTE It would be preferable to perform the initial charge in the season when the probability of having five “good
sunny days” consecutively is the highest.
Figure 1 – Test 2, Phase A: initial charge cycles
6.4.3.4.2 Phase B: operating conditions
This phase is dedicated to run the system over a long period in order to check its ability to
provide the required services under local operating conditions.
Phase B shall be performed immediately after Phase A.
Figure 2 illustrates the cycles to be performed.
The time for start is chosen a short while before sunrise.
The charging of the battery is controlled by the charge controller provided within the system.
The loads are switched on and off according to the load profile, either manually by the
laboratory operator or automatically by a programmable controller.
Between sunrise and sunset, the system is intended to be both able to charge the battery and
to supply energy to loads (according to the load profile).

After sunset, the system is intended to be able to supply the loads according to the load
profile which reflects as close as possible the way of life of the future customers.
The sunrise-sunset cycle shall be repeated, y, days (y ≥ 30) until 30 “good sunny days” have
been recorded.
NOTE It is better to perform the test during the sunny season and to ensure that, y, is less than or equal to 40
days. This is intended to shorten the duration of the test and thus reduce its cost and ensure good quality records.
The laboratory operator shall observe and record the start and the end of the service
according to each step of the load profile.
An example of an instruction sheet for the operator is given in Annex D. For the duration of
the test, the laboratory operator will live at the same rhythm as the future customers.

– 20 – TS 62257-9-6 © IEC:2008(E)

As a debugging period, a preliminary cycle will be performed in order to verify that the

programmable controller (if any) and all the test facilities are functional.

START Test 2,
Phase B
t = 0
Charge battery
Sunrise
under daylight
AND
power the loads according
to the load profile
t = y days
STOP Test 2,
Phase B
Repeat y days the cycle (until 30 “good sunny days”)

Power the loads according
...