IEC 61724-1:2017

Photovoltaic system performance - Part 1: Monitoring

IEC 61724-1:2017 outlines equipment, methods, and terminology for performance monitoring and analysis of photovoltaic (PV) systems. It addresses sensors, installation, and accuracy for monitoring equipment in addition to measured parameter data acquisition and quality checks, calculated parameters, and performance metrics. In addition, it serves as a basis for other standards which rely upon the data collected.

Performances des systèmes photovoltaïques - Partie 1: Surveillance

l’IEC 61724-1:2017 présente des équipements, des méthodes et une terminologie relatifs à la surveillance des performances et à l’analyse des systèmes photovoltaïques (PV). Elle traite des capteurs, des installations et de l’exactitude des équipements de surveillance en plus de l’acquisition des données et des contrôles qualité des paramètres mesurés, des paramètres calculés et des mesures de performances. En outre, elle sert de base à d’autres normes qui s’appuient sur les données collectées.

General Information

• Status: Published
• Publication Date: 02-Mar-2017
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 27.160 - Solar energy engineering
• Technical Committee: TC 82 - Solar photovoltaic energy systems
• Drafting Committee: WG 3 - TC 82/WG 3
• Current Stage: DELPUB - Deleted Publication
• Start Date: 01-May-2020
• Completion Date: 21-Jul-2021

Relations

• Replaces: IEC 61724:1998 - Photovoltaic system performance monitoring - Guidelines for measurement, data exchange and analysis
• Effective Date: 05-Sep-2023
• Revised: IEC 61724-1:2021 - Photovoltaic system performance - Part 1: Monitoring
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 61724-1 ®
Edition 1.0 2017-03
INTERNATIONAL
STANDARD
Photovoltaic system performance –
Part 1: Monitoring
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form

or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or

your local IEC member National Committee for further information.

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About the IEC
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International Standards for all electrical, electronic and related technologies.

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IEC 61724-1 ®
Edition 1.0 2017-03
INTERNATIONAL
STANDARD
Photovoltaic system performance –

Part 1: Monitoring
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-3988-9

– 2 – IEC 61724-1:2017 © IEC 2017

CONTENTS
FOREWORD . 5

INTRODUCTION . 7

1 Scope . 9

2 Normative references . 9

3 Terms and definitions . 10

4 Monitoring system classification . 13

5 General . 13

5.1 Measurement uncertainty . 13
5.2 Calibration . 14
5.3 Repeated elements . 14
5.4 Power consumption. 14
5.5 Documentation . 14
5.6 Inspection . 14
6 Data acquisition timing and reporting . 15
6.1 Sampling, recording, and reporting . 15
6.2 Timestamps . 16
7 Measured parameters . 16
7.1 General requirements . 16
7.2 Irradiance . 20
7.2.1 On-site irradiance measurement . 20
7.2.2 Satellite remote sensing of irradiance . 25
7.3 Environmental factors . 26
7.3.1 PV module temperature . 26
7.3.2 Ambient air temperature . 27
7.3.3 Wind speed and direction . 27
7.3.4 Soiling ratio . 28
7.3.5 Rainfall . 30
7.3.6 Snow . 30
7.3.7 Humidity . 30
7.4 Tracker system . 31
7.4.1 Single-axis trackers . 31
7.4.2 Dual-axis trackers for >20x systems . 31

7.5 Electrical measurements . 31
7.6 External system requirements . 32
8 Data processing and quality check . 32
8.1 Daylight hours . 32
8.2 Quality check . 33
8.2.1 Removing invalid readings . 33
8.2.2 Treatment of missing data . 33
9 Calculated parameters . 33
9.1 Overview . 33
9.2 Summations . 34
9.3 Irradiation . 34
9.4 Electrical energy . 35
9.4.1 General . 35
9.4.2 DC output energy . 35

9.4.3 AC output energy . 35

9.5 Array power rating . 35

9.5.1 DC power rating. 35

9.5.2 AC power rating . 35

9.6 Yields . 35

9.6.1 General . 35

9.6.2 PV array energy yield . 36

9.6.3 Final system yield . 36

9.6.4 Reference yield . 36

9.7 Yield losses . 36

9.7.1 General . 36
9.7.2 Array capture loss . 36
9.7.3 Balance of systems (BOS) loss . 36
9.8 Efficiencies . 37
9.8.1 Array (DC) efficiency . 37
9.8.2 System (AC) efficiency . 37
9.8.3 BOS efficiency . 37
10 Performance metrics. 37
10.1 Overview . 37
10.2 Summations . 38
10.3 Performance ratios . 38
10.3.1 Performance ratio . 38
10.3.2 Temperature-corrected performance ratios . 39
10.4 Performance indices . 40
11 Data filtering . 41
11.1 Use of available data . 41
11.2 Filtering data to specific conditions . 41
11.3 Reduced inverter, grid, or load availability . 41
Annex A (informative) Sampling interval . 42
A.1 General considerations . 42
A.2 Time constants . 42
A.3 Aliasing error . 42
A.4 Example . 43
Annex B (informative) Module backsheet temperature sensor selection and
attachment . 44

B.1 Objective . 44
B.2 Sensor and material selection . 44
B.2.1 Optimal sensor types . 44
B.2.2 Optimal tapes . 44
B.2.3 Cyanoacrylate adhesives and backsheet integrity . 44
B.3 Sensor attachment method . 45
B.3.1 Permanent versus temporary . 45
B.3.2 Attachment location . 45
B.3.3 Sensor attachment. 45
Annex C (informative) Derate factors . 48
Annex D (normative) Systems with local loads, storage, or auxiliary sources .
...

IEC 61724-1 ®
Edition 1.0 2017-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic system performance –
Part 1: Monitoring
Performances des systèmes photovoltaïques –
Partie 1: Surveillance
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: [phone]
3, rue de Varembé [e-mail]
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing 21 000 terms and definitions in
Technical Specifications, Technical Reports and other English and French, with equivalent terms in 16 additional
documents. Available for PC, Mac OS, Android Tablets and languages. Also known as the International Electrotechnical
iPad. Vocabulary (IEV) online.

IEC publications search - webstore.iec.ch/advsearchform IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a 67 000 electrotechnical terminology entries in English and
variety of criteria (reference number, text, technical French extracted from the Terms and Definitions clause of
committee,…). It also gives information on projects, replaced IEC publications issued since 2002. Some entries have been
and withdrawn publications. collected from earlier publications of IEC TC 37, 77, 86 and

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IEC 61724-1 ®
Edition 1.0 2017-03
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Photovoltaic system performance –

Part 1: Monitoring
Performances des systèmes photovoltaïques –

Partie 1: Surveillance
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-5227-7

– 2 – IEC 61724-1:2017 © IEC 2017
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 9
2 Normative references . 9
3 Terms and definitions . 10
4 Monitoring system classification . 13
5 General . 13
5.1 Measurement uncertainty . 13
5.2 Calibration . 14
5.3 Repeated elements . 14
5.4 Power consumption. 14
5.5 Documentation . 14
5.6 Inspection . 14
6 Data acquisition timing and reporting . 15
6.1 Sampling, recording, and reporting . 15
6.2 Timestamps . 16
7 Measured parameters . 16
7.1 General requirements . 16
7.2 Irradiance . 20
7.2.1 On-site irradiance measurement . 20
7.2.2 Satellite remote sensing of irradiance . 25
7.3 Environmental factors . 26
7.3.1 PV module temperature . 26
7.3.2 Ambient air temperature . 27
7.3.3 Wind speed and direction . 28
7.3.4 Soiling ratio . 28
7.3.5 Rainfall . 30
7.3.6 Snow . 30
7.3.7 Humidity . 31
7.4 Tracker system . 31
7.4.1 Single-axis trackers . 31
7.4.2 Dual-axis trackers for >20x systems . 31
7.5 Electrical measurements . 31
7.6 External system requirements . 32
8 Data processing and quality check . 32
8.1 Daylight hours . 32
8.2 Quality check . 33
8.2.1 Removing invalid readings . 33
8.2.2 Treatment of missing data . 33
9 Calculated parameters . 33
9.1 Overview . 33
9.2 Summations . 34
9.3 Irradiation . 34
9.4 Electrical energy . 35
9.4.1 General . 35
9.4.2 DC output energy . 35

9.4.3 AC output energy . 35
9.5 Array power rating . 35
9.5.1 DC power rating. 35
9.5.2 AC power rating . 35
9.6 Yields . 35
9.6.1 General . 35
9.6.2 PV array energy yield . 36
9.6.3 Final system yield . 36
9.6.4 Reference yield . 36
9.7 Yield losses . 36
9.7.1 General . 36
9.7.2 Array capture loss . 36
9.7.3 Balance of systems (BOS) loss . 36
9.8 Efficiencies . 37
9.8.1 Array (DC) efficiency . 37
9.8.2 System (AC) efficiency . 37
9.8.3 BOS efficiency . 37
10 Performance metrics. 37
10.1 Overview . 37
10.2 Summations . 38
10.3 Performance ratios . 38
10.3.1 Performance ratio .
...