SIST EN IEC 63409-3:2026

SLOVENSKI STANDARD
01-april-2026
Povezava fotonapetostnih sistemov za proizvodnjo električne energije z omrežjem
- Preskušanje opreme za pretvorbo električne energije - 3. del: Osnovni postopki
Photovoltaic power generating systems connection with grid - Testing of power
conversion equipment - Part 3: Basic operations
Photovoltaische Stromerzeugungssysteme mit Netzanschluss – Prüfung von
Energieumwandlungsanlagen Teil 3: Grundlegende Funktionen
Systèmes de production d’énergie photovoltaïque connectés au réseau électrique -
Essais des équipements de conversion de puissance - Partie 3: Opérations de base
Ta slovenski standard je istoveten z: EN IEC 63409-3:2026
ICS:
27.160 Sončna energija Solar energy engineering
29.240.01 Omrežja za prenos in Power transmission and
distribucijo električne energije distribution networks in
na splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 63409-3

NORME EUROPÉENNE
EUROPÄISCHE NORM January 2026
ICS 27.160
English Version
Photovoltaic power generating systems connection with the grid
- Testing of power conversion equipment - Part 3: Basic
operations
(IEC 63409-3:2025)
Systèmes de production d'énergie photovoltaïque Photovoltaische Stromerzeugungssysteme mit
connectés au réseau - Essais des équipements de Netzanschluss - Prüfung von Energieumwandlungsanlagen
conversion de puissance - Partie 3: Opérations de base Teil 3: Grundlegende Funktionen
(IEC 63409-3:2025) (IEC 63409-3:2025)
This European Standard was approved by CENELEC on 2026-01-07. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 63409-3:2026 E

European foreword
The text of document 82/2456/FDIS, future edition 1 of IEC 63409-3, prepared by TC 82 "Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN IEC 63409-3:2026.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2027-01-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2029-01-31
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 shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 63409-3:2025 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 61000-2-2:2002 NOTE Approved as EN 61000-2-2:2002 (not modified)
IEC 61000-4-27:2000 NOTE Approved as EN 61000-4-27:2000 (not modified)
IEC 61000-4-30 NOTE Approved as EN IEC 61000-4-30
IEC 61850-7-420 NOTE Approved as EN IEC 61850-7-420
IEC 61850-7-4 NOTE Approved as EN 61850-7-4
IEC 62053-23:2020 NOTE Approved as EN IEC 62053-23:2021 (not modified) +A11:2021
IEC 62109-1:2010 NOTE Approved as EN 62109-1:2010 (not modified)
IEC 62116 NOTE Approved as EN 62116
IEC 62446-1 NOTE Approved as EN 62446-1
IEC 60375 NOTE Approved as EN IEC 60375
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where 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.cencenelec.eu.
Publication Year Title EN/HD Year
IEC/TS 61836 - Solar photovoltaic energy systems - - -
Terms, definitions and symbols

IEC 63409-3 ®
Edition 1.0 2025-12
INTERNATIONAL
STANDARD
Photovoltaic power generating systems connection with the grid - Testing of
power conversion equipment -
Part 3: Basic operations
ICS 27.160  ISBN 978-2-8327-0818-7

IEC 63409-3:2025-12(en)
IEC 63409-3:2025 © IEC 2025
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 8
4 General requirements. 11
4.1 General conditions for testing . 11
4.1.1 Sequence of tests . 11
4.1.2 Test equipment conditions . 12
4.1.3 Manufacturer’s stated tolerance . 12
4.1.4 Required setting for EUT (equipment under test) . 12
4.1.5 PCE firmware used during the test . 12
4.1.6 Reporting the test results . 12
4.2 Test setup . 12
4.3 Parameters used in the tests . 13
5 Test procedures . 15
5.1 Steady state characteristics . 15
5.1.1 General. 15
5.1.2 Active power and reactive power . 15
5.1.3 Operable voltage . 16
5.1.4 Reactive power capability for low DC voltage . 18
5.1.5 Operable frequency . 19
5.1.6 Power factor . 20
5.2 Transient-response characteristics . 21
5.2.1 General. 21
5.2.2 Active power control . 21
5.2.3 Reactive power control . 22
5.2.4 Grid voltage variation . 23
5.2.5 Grid voltage phase angle variation . 25
5.2.6 Grid voltage unbalance . 26
5.2.7 Grid frequency variation. 27
Annex A (normative) Summary of test items . 29
Annex B (normative) Format for recording test results . 32
B.1 General . 32
B.2 Steady state characteristics . 32
B.2.1 Active power and reactive power (see 5.1.2) . 32
B.2.2 Operable voltage (see 5.1.3) and reactive power capability for low DC
voltage (see 5.1.4) . 33
B.2.3 Operable frequency (see 5.1.5) . 34
B.2.4 Power factor (see 5.1.6) . 34
B.3 Transient-response characteristics . 35
B.3.1 Active power control (see 5.2.2) . 35
B.3.2 Reactive power control (see 5.2.3) . 36
B.3.3 Grid voltage variation (see 5.2.4) . 37
B.3.4 Grid voltage phase angle variation (see 5.2.5) . 38
B.3.5 Grid voltage unbalance (see 5.2.6) . 39
IEC 63409-3:2025 © IEC 2025
B.3.6 Grid frequency variation (see 5.2.7) . 40
Annex C (informative) Examples of testing environments . 42
C.1 General . 42
C.2 Recommended specification of power supplies . 44
C.3 Recommended specification of measuring instruments . 45
Annex D (normative) Supplemental information for settling time measurement . 47
Annex E (normative) Sign conventions for measurements of voltage, current and
power . 48
E.1 General . 48
E.2 Reference polarity and direction . 48
E.2.1 Reference polarity of voltage . 48
E.2.2 Reference direction of current . 48
E.2.3 Sign conventions for measurements of voltage, current and power . 49
E.3 Reference frame of active and reactive power . 49
E.4 Physical meanings of the power flows of generators in regional standards . 54
Annex F (normative) Grid voltage unbalance – test condition . 56
F.1 General . 56
F.2 Causes and definitions of unbalanced grid voltage . 56
F.3 Test conditions . 56
Annex G (informative) Phase angle variation of grid voltage – alternative test setup . 57
G.1 General . 57
G.2 Alternative test setup and test procedure . 57
Annex H (informative) Fundamental principle of reactive power reduction with lower
DC voltage. 58
H.1 General . 58
H.2 Controllability limit . 58
Annex I (informative) Grid support functions covered in IEC 63409 series . 62
Annex J (informative) Influence of MPPT control and PV simulator to the test results . 63
J.1 General . 63
J.2 DC power supply and MPPT control of PCE . 63
J.2.1 DC power supply. 63
J.2.2 MPPT control. 63
J.3 Influence of the PV simulator . 63
Bibliography . 66

Figure 1 – Scopes of IEC 63409 series . 7
Figure 2 – Example of step response . 11
Figure 3 – Example of a test setup . 13
Figure 4 – Example operational parameters in P-Q capability curve of PCE in Producer
Reference Frame (PRF) . 15
Figure 5 – Example of settling time measurement for grid voltage variation test . 25
Figure 6 – Example of settling time measurement for grid frequency variation. 28
Figure B.1 – P-Q capability curve showing active power and reactive power test results
and power factor test results (example) . 33
Figure B.2 – Active power control test waveform example when active power setpoint
was changed from 100 % . 36
Figure B.3 – Reactive power control test waveform example when reactive power
setpoint was changed from 52,7 % to 0 % . 37
IEC 63409-3:2025 © IEC 2025
Figure B.4 – Grid voltage variation test waveform example when AC voltage was
changed from 100 % to 110 % . 38
Figure B.5 – Phase angle of grid voltage change test waveform example (10-degree
step change was applied to AC voltages for illustrative purpose) . 39
Figure B.6 – Grid voltage unbalance test waveform example when negative sequence
voltage was applied to AC voltages . 40
Figure B.7 – Grid frequency variation test waveform example when AC frequency was
changed from 50 Hz to 50,5 Hz . 41
Figure C.1 – Example of a testing environment . 42
Figure D.1 – Example of settling time measurement for grid voltage variation in case
the settled power is different from the original steady state . 47
Figure E.1 – Reference polarity of voltage. 48
Figure E.2 – Reference polarity of current . 48
Figure E.3 – Reference polarity and direction for the measurements for DER . 49
Figure E.4 – Reference polarity and direction for the measurements for load . 49
Figure E.5 – Rotating vector voltage and current for load . 50
Figure E.6 – Rotating vector voltage and current for DER . 50
Figure E.7 – Complex power for load . 52
Figure E.8 – Complex power for DER . 52
Figure E.9 – Power quadrants for load . 53
Figure E.10 – Power quadrants for DER . 53
Figure G.1 – Configuration of an alternative test setup . 57
Figure H.1 – Basic configuration of a power conversion equipment . 58
Figure H.2 – EUT voltage and current vector diagram and operating point depicted in
the PQ curve with sufficient U (over-excited) . 60
ac
Figure H.3 – EUT voltage and current vector diagram and operating point depicted in
the PQ curve with small U (over-excited) . 60
ac
Figure H.4 – EUT voltage and current vector diagram and operating point depicted in
the PQ curve with small U (under-excited) . 60
ac
Figure H.5 – EUT voltage and current vector diagram and operating point depicted in
the PQ curve during inflexion operating point (over-excited). 61
Figure J.1 – PV simulator characteristics examples . 63
Figure J.2 – Active power control test waveform with constant DC voltage source and
no MPPT . 64
Figure J.3 – Active power control test waveform with PV simulator and MPPT enabled . 65
Figure J.4 – Examples of operational point movement of a PCE during Active power
control tests . 65

Table 1 – Parameters defined for the tests . 14
Table 2 – Test conditions for operable voltage test . 18
Table 3 – Test conditions for operable frequency test . 20
Table 4 – Test cases for grid voltage unbalance . 27
Table A.1 – Test items for steady state characteristics (example) . 29
Table A.2 – Test items for transient-response characteristics (example) . 30
Table B.1 – Record of active power and reactive power test (example) . 32
Table B.2 – Record of operable voltage test (example) . 34
IEC 63409-3:2025 © IEC 2025
Table B.3 – Record of operable frequency test (example) . 34
Table B.4 – Record of power factor test (example) . 35
Table B.5 – Record of active power control test (example) . 35
Table B.6 – Record of reactive power control test (example) . 36
Table B.7 – Record of grid voltage variation test (example). 37
Table B.8 – Record of grid voltage phase angle variation test (example) . 38
Table B.9 – Record of grid voltage unbalance test (example) . 39
Table B.10 – Record of grid frequency variation test (example) . 40
Table C.1 – Required functions for power supplies . 43
Table C.2 – Electrical quantity measured with measuring instruments or devices . 43
Table C.3 – Recommended specifications for power supplies . 44
Table C.4 – Recommended specifications of power quality measurement . 45
Table C.5 – Recommended specifications of waveform monitoring and recording
device . 46
Table E.1 – Physical meanings of the power flows of loads . 53
Table E.2 – Physical meanings of the power flows of generators . 54
Table E.3 – Physical meanings of the power flows of generators in Japan . 54
Table E.4 – Physical meanings of the power flows of generators in IEEE 1547.1. 54
Table E.5 – Physical meanings of the power flows of generators in EN 50549-10 . 54
Table E.6 – Physical meanings of the power flows of generators in AS/NZS 4777.2 . 55
Table I.1 – Grid support functions covered in IEC 63409 series . 62

IEC 63409-3:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Photovoltaic power generating systems connection with the grid -
Testing of power conversion equipment -
Part 3: Basic operations
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,
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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
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6) All users should ensure that they have the latest edition of this publication.
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members of its technical committees and IEC National Committees for any personal injury, property damage or
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 63409-3 has been prepared by IEC technical committee 82: Solar photovoltaic energy
systems. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
82/2456/FDIS 82/2525/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
IEC 63409-3:2025 © IEC 2025
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 63409 series, published under the general title Photovoltaic power
generating systems connection with the grid – Testing of power conversion equipment, can be
found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
IEC 63409-3:2025 © IEC 2025
INTRODUCTION
This document gives test procedures for confirming the basic operation characteristics of power
conversion equipment (PCE).
Part 3 confirms basic power conversion control of PCE at steady state condition and at transient
response. Figure 1 shows the relationships of the seven parts in the IEC 63409 series. Part 3
is focused on the control functions in PCE with respect to power conversion. Power flow control
and grid support functions will generate active and reactive power commands according to the
grid conditions. The commands are sent to power conversion control, and power conversion
control will make current or voltage references, which manipulate signals for the switching
devices.
It is important to confirm the basic control performance of the PCE as power conversion
equipment without power flow control and grid support functions, so that additional functions
such as power flow control and grid support functions can perform appropriately.
The responses of PCE against abnormal grid conditions will be covered in Part 4 (IEC 63409-4).
Power quality of the PCE output will be covered in Part 5 (IEC 63409-5).
Power flow control and grid support functions will be covered in Part 6 (IEC 63409-6).
Responses against commands through communication will be covered Part 7 (IEC 63409-7).

Figure 1 – Scopes of IEC 63409 series

IEC 63409-3:2025 © IEC 2025
1 Scope
This document specifies test procedures for confirming the basic operational characteristics of
power conversion equipment (PCE) for use in photovoltaic (PV) power systems with or without
energy storage. The basic operational characteristics are the capability of the PCE before any
limitations due to internal settings are applied to the PCE to meet specific grid support functions
or specific behaviours against abnormal changes.
This document covers the testing of the following items:
a) Steady state characteristics
Test procedures to confirm operable range of PCE at steady state condition are described.
The operable ranges in apparent power, active power, reactive power, power factor, grid
voltage and grid frequency are confirmed according to the test procedures.
b) Transient-response characteristics
Test procedures to confirm PCE’s response against a change of operational condition are
described.
Transient-response characteristics to be confirmed are response behaviours against:
• Active power set point change and reactive power set point change
• Grid voltage change, phase angle change, voltage unbalance and frequency change
This document only considers the changes within normal (continuous) operable ranges.
Therefore, the behaviours against abnormal changes and grid support functions are out of the
scope and are covered in other parts of this series.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC TS 61836, Solar photovoltaic energy systems - Terms, definitions and symbols
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC TS 61836 as well as the
following apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1
power conversion equipment
PCE
electrical device converting one kind of electrical power from a voltage or current source into
another kind of electrical power with respect to voltage, current and frequency
[SOURCE: IEC 62109-1:2010, 3.66, modified – the note to entry has been omitted.]
IEC 63409-3:2025 © IEC 2025
3.2
grid support functions
PCE’s functions which control either active power or reactive power, or both, according to pre-
defined characteristics or set point command to support stabilizing the power quality of the grid
the PCE is connected to
3.3
maximum power point tracking
MPPT
PCE’s control function whereby the operation of PV array or module is always at or near the
maximum power point
[SOURCE: IEC TS 61836:2016, 3.4.43.4, modified – “control strategy whereby PV array
operation” has been replaced by “PCE’s control function whereby the operation of PV array or
module”, the note to entry has been omitted.]
3.4
steady state
equilibrium state in which the relevant characteristics remain constant with time
[SOURCE: IEC 60050-103:2009, 103-05-01, modified – the original definition has been changed
to adopt usage in PCE testing: “state of a physical system” has been replaced by “equilibrium
state”, the note to entry has been omitted.]
3.5
step response time
for a step response the duration of the time interval between the instant of the step change of
an input variable and the instant when the output variable reaches for the first time a specified
percentage of the difference between the final and the initial steady-state value
Note 1 to entry: See Figure 2.
[SOURCE: IEC 60050-351:2013, 351-45-36, modified – the note to entry has been omitted.]
3.6
settling time
for a step response the duration of the time interval between the instant of the step change of
an input variable and the instant, when the difference between the step response and their
steady-state value remains smaller than the transient value tolerance
Note 1 to entry: See Figure 2.
[SOURCE: IEC 60050-351:2013, 351-45-37, modified – the note to entry has been omitted.]
3.7
overshoot
for a step response of a transfer element the maximum transient deviation from the final steady-
state value of the output variable, usually expressed in percent of the difference between the
final and the initial steady-state values and for reference-variable step response or disturbance-
variable step response of a control system the maximum transient deviation from the desired
value
Note 1 to entry: See Figure 2.
[SOURCE: IEC 60050-351:2013, 31-45-38]
IEC 63409-3:2025 © IEC 2025
3.8
dead time
duration of the time interval by which the output variable is shifted relative to the input variable
in a dead-time element
[SOURCE: IEC 60050-351:2013, 351-50-30, modified – “in a dead-time element” has been
moved from the beginning to the end of the definition, the note to entry has been omitted.]
3.9
tolerance
permitted deviation between the declared value of a quantity and the measured value
[SOURCE: IEC 60050-411:2007, 411-36-19]
3.10
tolerance band
permitted deviation range of measured signal from the defined target value
3.11
accuracy
quality which characterizes the ability of a measuring instrument
to provide an indicated value close to a true value of the measurand
[SOURCE: IEC 60050-311:2001, 311-06-08, modified – the notes to entry have been omitted.]
3.12
voltage unbalance
in a polyphase system, condition in which the r.m.s values of the phase voltages or the phase
angles between consecutive phases are not all equal
[SOURCE: IEC 60050-161:1990, 161-08-09]
IEC 63409-3:2025 © IEC 2025
a
For periodic behaviour
Key
1) For periodic behaviour
2) For aperiodic behaviour
u Input variable
U Initial value of the input variable
U Step height of the input variable
s
v Output variable
V , V Steady-state values before and after application of the step
0 ∞
v Overshoot (maximum transient deviation from the final steady-state value)
m
Tolerance band
2･Δv
s
T Step response time
sr
T Settling time
s
T Dead time
t
[SOURCE: IEC 60050-351:2013, 351-45-36]
Figure 2 – Example of step response
4 General requirements
4.1 General conditions for testing
4.1.1 Sequence of tests
The test may be performed in any order unless otherwise specified in this document. It is not
necessary to use the same sample for all tests unless otherwise specified in this document.
IEC 63409-3:2025 © IEC 2025
4.1.2 Test equipment conditions
Examples of the test equipment such as external power supplies and test instruments are
described in Annex C.
4.1.3 Manufacturer’s stated tolerance
The tolerance bands for ac voltage, frequency, active power, reactive power and the time
measurements can be subject to local regulations. If not, the manufacturer of the PCE under
evaluation shall state the tolerance.
4.1.4 Required setting for EUT (equipment under test)
All the grid support functions, some of which are listed as examples in Annex I, shall be disabled
throughout the test. If any one of the grid support functions is essential to perform the test, it is
permissible to enable it. In that case, it shall be written in the test report as remark that the
specific function was enabled during the test because it was essential to complete the test.
Maximum power point tracking (MPPT) control shall be configured as described in 4.2.
4.1.5 PCE firmware used during the test
The versions of the PCE firmware used during the test shall be recorded in the test report.
4.1.6 Reporting the test results
Test results shall be presented in the way shown in Annex B.
4.2 Test setup
During testing, the EUT’s DC and AC ports shall be connected to external DC and AC power
supplies according to EUT manufacturer’s instructions. The test circuit diagram with positions
of measurement sensors shall be recorded in the test report. Figure 3 shows the typical test
setup required for test items described in this document.
Apparent power, active power and reactive power shall be measured at AC ports of EUT. The
current measuring instruments at AC port of the EUT shall be installed so that the current
flowing from EUT to AC power supply is measured as positive. See Annex E for more detailed
definitions of sign conventions for measurements of voltage, current and power in this document.
The testing of the EUT shall not be influenced by the performance of DC power supply used for
the test. Therefore, where the EUT has the capability to disable MPPT control, it is allowed to
do so and a DC power supply that is able to provide constant voltage at any required power
levels shall be used. A PV simulator may be used provided that the test results are not
influenced by any DC instability by the PV simulator. In each case, remarks shall be written in
the test report to note the type of the DC power supply or PV simulator used in the test. See
Annex J for supplemental information regarding the influences from the PV simulator.
IEC 63409-3:2025 © IEC 2025
Figure 3 – Example of a test setup
4.3 Parameters used in the tests
The parameters in Table 1 are defined for the tests. Manufacturer shall declare the parameters
before starting the tests.
IEC 63409-3:2025 © IEC 2025
Table 1 – Parameters defined for the tests
Items Symbols Units Explanation
Minimum DC U V the minimum DC voltage for PCE to import or
dc_min
operating voltage export nominal active power continuously to
or from the grid
Nominal DC operating U V the nominal DC voltage for PCE to import or
dc_nom
DC power port voltage export nominal active power continuously to
or from the grid defined by the manufacturer
Maximum DC U V the maximum DC voltage for PCE to import or
dc_max
operating voltage export nominal active power continuously to
or from the grid
Maximum apparent S VA the maximum apparent power which flows
max
power continuously and can be controlled by the
PCE
Nominal active power P W the maximum active power which flows
nom
continuously and can be controlled by the
PCE
Maximum over- Q var the maximum over-excited (capacitive)
max,oe
excited reactive reactive power which flows continuously and
power can be controlled by the PCE
Maximum under- Q var the maximum under-excited (inductive)
max,ue
excited reactive reactive power which flows continuously and
power can be controlled by the PCE
Nominal AC voltage U V the rated AC voltage of the PCE
N
Continuous operable U V the maximum grid voltage at which the PCE
H
maximum AC voltage can operate and deliver power continuously
without tripping
Continuous operable U V the minimum grid voltage at which the PCE
AC power port
L
minimum AC voltage can operate and deliver power continuously
without tripping
Minimum over-excited PF - minimum over-excited power factor of the
min.oe
power factor at PCE where PV system can deliver maximum
maximum apparent apparent power continuously at nominal AC
power voltage
Minimum under- PF - minimum under-excited power factor of the
min.ue
excited power factor PCE where PV system can deliver maximum
at maximum apparent apparent power continuously at nominal AC
power voltage
Nominal frequency f Hz the rated AC frequency of the PCE
N
Continuous operable f Hz the maximum grid frequency at which the
H
maximum grid PCE can operate and deliver power
frequency continuously without tripping
Continuous operable f Hz the minimum grid frequency at which the PCE
L
minimum grid can operate and deliver power continuously
frequency without tripping
P-Q capability curve is used to visualize the operating area of the PCE in terms of active power
(P) and reactive power (Q). The horizontal axis is active power in watt, and the value is positive
when the PCE is producing power. The vertical axis is reactive power in var, and the value is
positive when the PCE’s reactive power is over-excited or injecting direction from Producer
Reference Frame (PRF). See Figure E.3 in Annex E for the directions of the measurements
referred to in this document.
The P-Q curve shape defines the operating area as well as nominal active power P ,
nom
maximum reactive power Q and Q , and minimum power factor PF and PF .
max,oe max,ue min.oe min.ue
IEC 63409-3:2025 © IEC 2025
An example P-Q capability curve for PCE is shown in Figure 4. In this case, all four quadrants
are used to show the PCE’s capability in both positive and negative active power direction. If a
PCE can only produce power, the curve will be drawn only using two quadrants. The parameters
shown in the curve correspond to the parameters in Table 1.

Figure 4 – Example operational parameters in P-Q capability curve of
PCE in Producer Reference Frame (PRF)
5 Test procedures
5.1 Steady state characteristics
5.1.1 General
This subclause 5.1 describe
...