SIST EN 62670-2:2015

Concentrator photovoltaic (CPV) performance testing - Part 2: Energy measurement

This part of IEC 62670 specifies the minimum requirements for determining the energy output
and performance ratio for CPV modules, arrays, assemblies and power plants using an onsun,
measurement based method.
The purpose of this International Standard is to define testing methods, to establish a
standard energy measurement for CPV modules, arrays, assemblies and power plants, and to
specify the minimum reporting information.

Konzentrator-Photovoltaik (CPV) Leistungsmessung - Teil 2: Energiemessung

Concentrateurs photovoltaïques (CPV) - Essai de performances - Partie 2: Mesure de l'énergie

L'IEC 62670-2:2015 spécifie les exigences minimales pour déterminer la production d'énergie et le rapport de performance des modules, des champs, des ensembles et des centrales photovoltaïques à concentration utilisant une méthode basée sur la mesure sous exposition au soleil. Cette Norme internationale est destinée à définir des méthodes d'essai, à établir une mesure normalisée de l'énergie pour les modules, les champs, les ensembles et les centrales photovoltaïques à concentration, et à spécifier les informations minimales à rapporter.

Preskušanje zmogljivosti fotonapetostnih koncentratorjev (CPV) - 2. del: Merjenje energije (IEC 62670-2:2015)

Ta del standarda IEC 62670 določa minimalne zahteve za določanje razmerja med izhodno energijo in zmogljivostjo za module CPV, nize, sestave in elektrarne z uporabo merilne metode »onsun«. Namen tega mednarodnega standarda je opredeliti preskusne metode za uvedbo standardne meritve energije za module CPV, nize, sestave in elektrarne ter določiti minimalne informacije za poročanje.

General Information

• Status: Published
• Publication Date: 06-Aug-2015
• ICS: 27.160 - Solar energy engineering
• Technical Committee: PVS - Solar photovoltaic energy systems
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 08-Jul-2015
• Due Date: 12-Sep-2015
• Completion Date: 07-Aug-2015
• Ref Project: EN 62670-2:2015 - Photovoltaic concentrators (CPV) - Performance testing - Part 2: Energy measurement

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 62670-2:2015
01-september-2015
Preskušanje zmogljivosti fotonapetostnih koncentratorjev (CPV) - 2. del: Merjenje
energije (IEC 62670-2:2015)
Concentrator photovoltaic (CPV) performance testing - Part 2: Energy measurement
Konzentrator-Photovoltaik (CPV) Leistungsmessung - Teil 2: Energiemessung
Concentrateurs photovoltaïques (CPV) - Essai de performances - Partie 2: Mesure de
l'énergie
Ta slovenski standard je istoveten z: EN 62670-2:2015
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
SIST EN 62670-2:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62670-2:2015

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SIST EN 62670-2:2015


EUROPEAN STANDARD EN 62670-2

NORME EUROPÉENNE

EUROPÄISCHE NORM
June 2015
ICS 27.160

English Version
Photovoltaic concentrators (CPV) - Performance testing -
Part 2: Energy measurement
(IEC 62670-2:2015)
Concentrateurs photovoltaïques (CPV) - Essai de Konzentrator-Photovoltaik (CPV) Leistungsmessung -
performances - Partie 2: Mesure de l'énergie Teil 2: Energiemessung
(IEC 62670-2:2015) (IEC 62670-2:2015)
This European Standard was approved by CENELEC on 2015-06-11. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.


European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
 Ref. No. EN 62670-2:2015 E

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SIST EN 62670-2:2015
EN 62670-2:2015
Foreword
The text of document 82/940/FDIS, future edition 1 of IEC 62670-2, prepared by IEC/TC 82 "Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 62670-2:2015

The following dates are fixed:
(dop) 2016-03-11
• latest date by which the document has to be
implemented at national level by
publication of an identical national
standard or by endorsement
• latest date by which the national (dow) 2018-06-11
standards conflicting with the
document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.

Endorsement notice
The text of the International Standard IEC 62670-2:2015 was approved by CENELEC as a European
Standard without any modification.
2

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SIST EN 62670-2:2015
EN 62670-2:2015
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.

NOTE 1 When an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.

NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu

Publication Year Title EN/HD Year

IEC 62670-1 -  Photovoltaic concentrators (CPV) - EN 62670-1 -
Performance testing -
Part 1: Standard conditions
ISO/IEC 17025 -  General requirements for the competence - -
of testing and calibration laboratories
ISO 8601 2004 Data elements and interchange formats - - -
Information interchange - Representation
of dates and times
ISO 9060 -  Solar energy; specification and - -
classification of instruments for measuring
hemispherical solar and direct solar
radiation
ISO 9847 -  Solar energy - Calibration of field - -
pyranometers by comparison to a
reference pyranometer
JCGM 100 2008 Evaluation of measurement data - - -
Guide to the expression of uncertainty in
measurement

3

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SIST EN 62670-2:2015




IEC 62670-2

®


Edition 1.0 2015-05




INTERNATIONAL



STANDARD




NORME



INTERNATIONALE
colour

inside










Photovoltaic concentrators (CPV) – Performance testing –

Part 2: Energy measurement




Concentrateurs photovoltaïques (CPV) – Essai de performances –

Partie 2: Mesure de l'énergie
















INTERNATIONAL

ELECTROTECHNICAL

COMMISSION


COMMISSION

ELECTROTECHNIQUE


INTERNATIONALE




ICS 27.160 ISBN 978-2-8322-2627-8



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

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 62670-2:2015
– 2 – IEC 62670-2:2015 © IEC 2015
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
4 Description of the method . 9
5 Selection of subset under test . 10
6 Operation, maintenance and cleaning . 10
7 Downtimes and unavailability . 11
8 Parasitic energy. 11
9 Data acquisition . 11
9.1 General requirements . 11
9.1.1 Data acquisition system (DAS) . 11
9.1.2 Sampling interval . 12
9.2 Mandatory measurements . 13
9.2.1 General . 13
9.2.2 Direct normal irradiance. 13
9.2.3 Global plane of array irradiance . 13
9.2.4 Ambient air temperature . 14
9.2.5 Wind speed . 14
9.2.6 Electrical power or energy . 14
9.2.7 Cold source temperature (actively cooled systems only) . 14
10 Data post-processing . 14
10.1 Calculation of energy from integrated power values . 14
10.2 Calculation of energy from discrete power values . 15
10.3 Calculation of the DNI time series . 15
10.4 Calculation of the active AC or DC energy . 17
11 Calculation of the performance ratio . 18
11.1 General . 18
11.2 AC performance ratio . 18
11.3 DC performance ratio . 19
12 Derived parameters . 20
13 Report . 20
Annex A (informative) Some suggested ways to filter data in order to identify incorrect
data . 22
Annex B (informative) Best practices for power plant energy measurement . 23
Annex C (normative) Optionally derived parameters. 24
C.1 General . 24
C.2 Energy Production Rate (EPR) . 24
C.3 Capacity Factor (CF) . 24

Figure 1 – Nomenclature of angles used in Formula (2) . 17

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SIST EN 62670-2:2015
IEC 62670-2:2015 © IEC 2015 – 3 –
Table 1 – Steps of the energy measurement procedure . 10
Table 2 – Mandatory measurements. . 13

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SIST EN 62670-2:2015
– 4 – IEC 62670-2:2015 © IEC 2015
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

PHOTOVOLTAIC CONCENTRATORS (CPV) –
PERFORMANCE TESTING –

Part 2: Energy measurement

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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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
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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.
International Standard IEC 62670-2 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
The text of this standard is based on the following documents:
FDIS Report on voting
82/940/FDIS 82/969/RVD

Full information on the voting for the approval of this standard 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.

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SIST EN 62670-2:2015
IEC 62670-2:2015 © IEC 2015 – 5 –
A list of all parts in the IEC 62670 series, published under the general title Photovoltaic
Concentrators (CPV) – Performance testing, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.

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.

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SIST EN 62670-2:2015
– 6 – IEC 62670-2:2015 © IEC 2015
INTRODUCTION
IEC 62670 series establishes requirements for evaluating concentrator PV performance. It is
written to be applicable to all concentrator PV technologies that have a geometric
concentration ratio greater than 3× and require tracking.
Included in the IEC 62670 series of standards are definitions of the standard conditions and
methods to be used for assessing CPV performance.
IEC 62670-1 defines a standard set of conditions so that power ratings noted on data sheets
and nameplates have a standard basis.
IEC 62670-2 describes an on-sun, measurement based method for determining the energy
output and performance ratio for CPV arrays, assemblies and power plants.
IEC 62670-3 (under consideration) describes methods for providing a CPV power assessment
under a set of standard conditions, enabling assessments both indoors and outdoors.
IEC 62670-4 (under consideration) describes methods for calculating the prospective
electrical energy output of CPV modules, arrays, assemblies and power plants based on the
measurements carried out in IEC 62670-2.

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SIST EN 62670-2:2015
IEC 62670-2:2015 © IEC 2015 – 7 –
PHOTOVOLTAIC CONCENTRATORS (CPV) –
PERFORMANCE TESTING –

Part 2: Energy measurement



1 Scope
This part of IEC 62670 specifies the minimum requirements for determining the energy output
and performance ratio for CPV modules, arrays, assemblies and power plants using an on-
sun, measurement based method.
The purpose of this International Standard is to define testing methods, to establish a
standard energy measurement for CPV modules, arrays, assemblies and power plants, and to
specify the minimum reporting information.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62670-1, Photovoltaic concentrators (CPV) – Performance testing – Part 1: Standard
conditions
ISO/IEC 17025, General requirements for the competence of testing and calibration
laboratories
ISO 8601:2004, Data elements and interchange formats – Information interchange –
Representation of dates and times
ISO 9060, Solar energy – Specification and classification of instruments for measuring
hemispherical solar and direct solar radiation
ISO 9847, Solar energy – Calibration of field pyranometers by comparison to a reference
pyranometer
JCGM 100:2008, Evaluation of measurement data – Guide to the expression of uncertainty in
measurement
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
active AC energy
real AC energy (excluding reactive energy)

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SIST EN 62670-2:2015
– 8 – IEC 62670-2:2015 © IEC 2015
3.2
actively cooled
CPV system that requires some type of media (fluid, gas, etc.) to facilitate the transfer of
thermal energy from one body to another. This could be by means of force air, pumps,
thermo-electric cooler, gas transfer or any other means not covered by passive cooling.
3.3
concentrator
qualifies photovoltaic devices or systems that use concentrated sunlight
Note 1 to entry: Concentrator photovoltaic technology is usually designated as CPV.
3.4
concentrator optics
optical component that performs one or more of the following functions from its input to
output: increasing the light intensity, filtering the spectrum, modifying light intensity
distribution, or changing light direction
Note 1 to entry: Typically, it is a (refractive) lens or a (reflective) mirror. A primary optic receives un-concentrated
sunlight directly from the sun. A secondary optic receives concentrated or modified sunlight from a primary optic
and directs it to a cell or a tertiary optic.
3.5
coolant
fluid, gas or other media that is circulated through or around a CPV device and transfers the
thermal energy out of the device
3.6
CPV receiver
group of one or more solar cells and secondary optics (if present) that accepts concentrated
sunlight and incorporates the means for thermal and electric energy transfer
Note 1 to entry: A receiver can be made of several sub-receivers.
3.7
CPV module
group of receivers, optics, and other related components, such as interconnection and
mounting, that accepts un-concentrated sunlight
Note 1 to entry: All above components are usually prefabricated as one unit, and the focus point is not field-
adjustable.
3.8
CPV array
group of modules mounted on a tracking device and electrically interconnected
Note 1 to entry: Examples are illustrated in IEC 62108.
3.9
CPV assembly
group of receivers, optics, and other related components, such as interconnects and mounts,
that accepts un-concentrated sunlight
Note 1 to entry: All above components would usually be shipped separately and need some field installation, and
the focus point is field-adjustable.
3.10
CPV power plant
group of CPV assemblies or CPV arrays electrically interconnected to provide output power to
a load

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SIST EN 62670-2:2015
IEC 62670-2:2015 © IEC 2015 – 9 –
3.11
data acquisition system
DAS
system that typically measures analog values, converts them to digital values and stores them
3.12
device under test
DUT
CPV module(s), array(s), assembly/assemblies or power plant(s) the procedure described in
this International Standard is applied to
3.13
direct normal irradiance
DNI
irradiance received from a small solid angle centered on the sun’s disc on a plane
perpendicular to the sun’s rays
3.14
direct plane of array irradiance
DPOAI
irradiance received from a small solid angle centered on the sun’s disc in the plane of the
CPV array
3.15
global plane of array irradiance
GPOAI
total irradiance received from the sun as a combination of direct normal irradiance and all
forms of diffuse light in the plane of the PV array
3.16
gross power/energy
is equal to the net power/energy plus the parasitic power/energy
3.17
net power/energy
is equal to the gross power/energy minus the parasitic power/energy
3.18
normal incidence pyrheliometer
NIP
radiometer designed for measuring the direct irradiance as described in ISO 9060
3.19
parasitic power/energy
power/energy used by the CPV power plant to operate including, but not restricted to, the
power and energy used for tracking, control, cooling, drying, measurement, and data
acquisition
3.20
passively cooled
cooling with a device that does not require an active energy supply
4 Description of the method
The method of energy measurement of a CPV system is shown in Table 1.

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SIST EN 62670-2:2015
– 10 – IEC 62670-2:2015 © IEC 2015
Table 1 – Steps of the energy measurement procedure
Step Action
1 Select and describe DUT
2 Describe site, location, surroundings
3 Check calibration of DAS, install DAS
4 Start measurements
a b b b
Mandatory: Time, DNI, GPOAI , gross power/energy , parasitic power/energy , net power/energy ,
ambient temperature, wind speed
Optionally: Module/receiver temperature, voltage(s), current(s), coolant temperature, wind direction,
air humidity
5 Conduct and document operation and maintenance program, e.g. cleaning of modules and NIPs,
greasing, tightening of chains
Update logbook, e.g. on rainfall events or unscheduled maintenance events
6 Stop measurements
7 Recheck DAS
8 Inspect recorded measurements in order to identify incorrect data, determine DNI time series used to
calculate the DNI energy
9 Calculate the DNI energy, gross energy, net energy, uncertainty values, performance ratio, optionally
derived parameters
10 Create report
a
 Mandatory for systems that have a geometric concentration ratio of less than 10×.
b
 At least two of the three quantities need to be measured in order to calculate the third quantity.

5 Selection of subset under test
For the energy measurement of a CPV power plant, all components of the system that will be
installed with the modules shall be incorporated, so that all parasitic loads of the system are
present for the measurement. At times, it may be useful to apply the procedure to a subset of
a power plant. In this case, the report shall document the subset that was chosen and the
rationale for the choice.
6 Operation, maintenance and cleaning
The CPV modules, arrays, assemblies or power plant shall be operated as suggested by the
manufacturer. If the DUT is actively cooled, the flow rate of the coolant and the coolant
composition shall be set as suggested by the manufacturer. The flow rate and coolant
composition shall be recorded in the testing report.
The scheduled maintenance program as suggested by the manufacturer for all components of
the power plant shall be observed, including but not limited to cleaning, greasing, tightening of
chains and scheduled change of parts. In particular, cleaning of modules/concentrator optics
shall be done at the same frequency as suggested by the manufacturer. In the absence of a
suggested frequency, the cleaning of concentrator optics will be performed at a reasonable
frequency according to the site conditions.
All scheduled and unscheduled maintenance and cleaning activities shall be noted in the
report in detail including time and duration of each event. For each cleaning event it shall be
noted whether all of the modules/concentrator optics or only a part thereof were cleaned. In
case of a partial cleaning the cleaned part shall be specified unambiguously, e.g. by providing
the module or tracker identifiers of the cleaned part.

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SIST EN 62670-2:2015
IEC 62670-2:2015 © IEC 2015 – 11 –
The NIPs should be cleaned ideally daily, but shall be cleaned at least once per week and
each cleaning event shall be noted including time and duration in the report.
7 Downtimes and unavailability
All periods of non-functionality of either the CPV modules, arrays, assemblies or power plant
or the sensors or the DAS shall be noted including time and duration and if possible the cause
in the report.
8 Parasitic energy
The measurement shall accurately include the parasitic energy consumed by the DUT.
Parasitic energy includes, but is not restricted to:
– Energy consumed by the tracking system, including the energy consumed for coming on
track, going to stow, and parking the CPV system at night.
– Energy consumed by the control system.
– Energy consumed by the drying system where relevant.
– Energy consumed by the cooling pumps and cooling fans, including the cooling of the
inverters, where relevant.
– Energy consumed by the electrical equipment such as inverters, transformers and switch
gear.
– Energy consumed by the air conditioning or cooling system in the control room and in the
inverter room of the power plant where relevant.
All energy consumed by monitoring and data acquisition equipment not essential for the
operation of the power plant shall be considered part of the load and shall not be considered
as parasitic energy. If only one or a few modules, arrays or assemblies within a power plant
are tested following this International Standard, the parasitic energy drawn by the complete
power plant will be divided by the total number of modules, arrays or assemblies in the power
plant and multiplied by the number of modules, arrays or assemblies under test.
In cases where parasitic energy is consumed intermittently, e.g. the energy used by the
tracking system, particular attention shall be paid to ensuring accurate measurement. When in
doubt, the maximum possible parasitic energy shall be used. Details of the calculation will be
included in the testing report.
9 Data acquisition
9.1 General requirements
9.1.1 Data acquisition system (DAS)
9.1.1.1 General
An automatic, microprocessor-based, DAS is required for this standard. The total uncertainty
of the DAS shall be determined using JCGM 100:2008 as guidance and by checks as laid out
below and detailed in the test report.
The DAS excluding sensors can be checked by applying the simulated input signals specified
below, or by other means agreed upon between the manufacturer and the customer. The
calibrations shall be checked at the beginning and the end of the test. If the check identifies
that the calibration has drifted outside of the specification, an assessment of the associated
uncertainty/error shall be completed and included in the report.
The channels of the DAS can be checked separately or at the same time.

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9.1.1.2 Types of input signals to be checked
– Direct Normal Irradiance power density
– Ambient air temperature
– Wind speed
– Gross power/ener
...