Simulators used for testing of photovoltaic power conversion equipment - Recommendations - Part 1: AC power simulators

IEC TS 63106-1:2020 provide recommendations for Low Voltage (LV) AC power simulators used for testing utility interactive photovoltaic power conversion equipment (PCE). This document establish terminology, and create a framework for, and provide guidance regarding the electrical performance of AC power simulators used to test utility interactive photovoltaic (PV) power conversion equipment (PCE) for compliance with grid interconnection standards.
It serves as a generalized guideline for the development of AC power simulators used within a test and evaluation system for PV PCEs.

General Information

Status
Published
Publication Date
18-Nov-2020
Current Stage
PPUB - Publication issued
Completion Date
19-Nov-2020
Ref Project

Buy Standard

Technical specification
IEC TS 63106-1:2020 - Simulators used for testing of photovoltaic power conversion equipment - Recommendations - Part 1: AC power simulators
English language
39 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

IEC TS 63106-1
Edition 1.0 2020-11
TECHNICAL
SPECIFICATION
Simulators used for testing of photovoltaic power conversion equipment –
Recommendations –
Part 1: AC power simulators
IEC TS 63106-1:2020-11(en)
---------------------- Page: 1 ----------------------
THIS PUBLICATION IS COPYRIGHT PROTECTED
Copyright © 2020 IEC, Geneva, Switzerland

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.
IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
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 corrigendum or an amendment might have been published.

IEC publications search - webstore.iec.ch/advsearchform Electropedia - www.electropedia.org

The advanced search enables to find IEC publications by a The world's leading online dictionary on electrotechnology,

variety of criteria (reference number, text, technical containing more than 22 000 terminological entries in English

committee,…). It also gives information on projects, replaced and French, with equivalent terms in 16 additional languages.

and withdrawn publications. Also known as the International Electrotechnical Vocabulary

(IEV) online.
IEC Just Published - webstore.iec.ch/justpublished

Stay up to date on all new IEC publications. Just Published IEC Glossary - std.iec.ch/glossary

details all new publications released. Available online and 67 000 electrotechnical terminology entries in English and

once a month by email. French extracted from the Terms and Definitions clause of

IEC publications issued since 2002. Some entries have been

IEC Customer Service Centre - webstore.iec.ch/csc collected from earlier publications of IEC TC 37, 77, 86 and

If you wish to give us your feedback on this publication or CISPR.
need further assistance, please contact the Customer Service
Centre: sales@iec.ch.
---------------------- Page: 2 ----------------------
IEC TS 63106-1
Edition 1.0 2020-11
TECHNICAL
SPECIFICATION
Simulators used for testing of photovoltaic power conversion equipment –
Recommendations –
Part 1: AC power simulators
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-9035-4

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

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TS 63106-1:2020 © IEC 2020
CONTENTS

FOREWORD ........................................................................................................................... 4

INTRODUCTION ..................................................................................................................... 6

1 Scope .............................................................................................................................. 7

2 Normative references ...................................................................................................... 7

3 Terms, definitions and abbreviated terms ........................................................................ 7

4 PCE types with respect to AC voltage levels and grid interconnection ............................. 9

5 Test setup for utility interactive PCEs ............................................................................ 10

5.1 General ................................................................................................................. 10

5.2 Test setup examples for utility interaction test ....................................................... 11

5.2.1 General ......................................................................................................... 11

5.2.2 Types of AC power simulator systems ........................................................... 11

5.2.3 Load .............................................................................................................. 12

5.2.4 Line impedance ............................................................................................. 13

6 General recommendations for AC power simulators ....................................................... 13

6.1 General ................................................................................................................. 13

6.1.1 Overview ....................................................................................................... 13

6.1.2 AC main connections ..................................................................................... 13

6.1.3 Output transformer ........................................................................................ 13

6.1.4 Number of phases and voltage range ............................................................. 13

6.1.5 Frequency ranges supplied to EUT ................................................................ 14

6.1.6 Voltage stability and accuracy ....................................................................... 14

6.1.7 Frequency stability and accuracy ................................................................... 14

6.1.8 AC output voltage harmonic distortion ........................................................... 14

6.1.9 Signal interface for hardware in the loop ........................................................ 15

6.1.10 Durability against impulse test voltage ........................................................... 15

6.1.11 Other requirements for test properties ........................................................... 15

6.2 AC power simulator performance and characteristics ............................................ 15

Bibliography .......................................................................................................................... 38

Figure 1 – Examples of ports .................................................................................................. 8

Figure 2 – Example of connection of DG systems to utility grid ............................................. 10

Figure 3 – Examples of fundamental setup of EUT test system ............................................. 11

Table 1 – Typical maximum harmonic voltage distortion (as per IEC 61000-4-7:2002) ......... 14

Table 2 – Grid qualification/Requalification – In-range voltage before

connection/reconnection ....................................................................................................... 16

Table 3 – Grid qualification/Requalification – In-range frequency before

connection/reconnection ....................................................................................................... 17

Table 4 – Power capability: Nameplate P, Q, S under normal and near-normal grid

conditions ............................................................................................................................. 18

Table 5 – Power capability: Limitation of P/Q/S/PF by setpoint ............................................. 19

Table 6 – Power capability: Ramp rate or soft start time-developing magnitude by

set rate ................................................................................................................................. 20

Table 7 – Grid protection tests – AC over-voltage (OV) and under-voltage (UV) trip

tests ..................................................................................................................................... 21

---------------------- Page: 4 ----------------------
IEC TS 63106-1:2020 © IEC 2020 – 3 –

Table 8 – Grid protection tests: OF/UF trips .......................................................................... 22

Table 9 – Grid protection tests: Anti-islanding ....................................................................... 23

Table 10 – Grid protection tests: ROCOF trips ...................................................................... 24

Table 11 – Grid protection tests: Open phase ....................................................................... 25

Table 12 – Power quality tests: Current harmonics, inter-harmonics, THDi ............................ 26

Table 13 – Power quality tests: Flicker (continuous) ............................................................. 27

Table 14 – Power quality tests: Current inrush (at connection switch close) .......................... 28

Table 15 – Power quality tests: Current imbalance ................................................................ 29

Table 16 – Power quality tests: Transient OV on load dump .................................................. 30

Table 17 – Grid support tests: UV/OV ride-through with/without Iq injection .......................... 31

Table 18 – Grid support tests: UF/OF ride-through ................................................................ 32

Table 19 – Grid support tests: ROCOF ride-through .............................................................. 33

Table 20 – Grid support tests: Phase-jump ride-through........................................................ 34

Table 21 – Grid support tests: P (f), PF (P, V), Q (V), P (V) .................................................. 35

Table 22 – External command response tests: Magnitude accuracy for P/Q/S/PF by

setpoint ................................................................................................................................. 36

Table 23 – External command response tests: Response to external setpoint changes

(response time, settling time) ................................................................................................ 37

---------------------- Page: 5 ----------------------
– 4 – IEC TS 63106-1:2020 © IEC 2020
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SIMULATORS USED FOR TESTING OF PHOTOVOLTAIC POWER
CONVERSION EQUIPMENT – RECOMMENDATIONS –
Part 1: AC power simulators
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 Publications.

8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

indispensable for the correct application of this publication.

9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent

rights. IEC shall not be held responsible for identifying any or all such patent rights.

The main task of IEC technical committees is to prepare International Standards. In exceptional

circumstances, a technical committee may propose the publication of a Technical Specification

when

• the required support cannot be obtained for the publication of an International Standard,

despite repeated efforts, or

• the subject is still under technical development or where, for any other reason, there is the

future but no immediate possibility of an agreement on an International Standard.

Technical Specifications are subject to review within three years of publication to decide

whether they can be transformed into International Standards.

IEC TS 63106-1, which is a Technical Specification, has been prepared by IEC technical

committee 82: Solar photovoltaic energy systems.
---------------------- Page: 6 ----------------------
IEC TS 63106-1:2020 © IEC 2020 – 5 –
The text of this Technical Specifications based on the following documents:
Draft TS Report on voting
82/1731/DTS 82/1776A/RVDTS

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 document has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts in the IEC 63106 series, published under the general title Simulators used for

testing of photovoltaic power conversion equipment – Recommendations, can be found on the

IEC web site.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC TS 63106-1:2020 © IEC 2020
INTRODUCTION

The objective of this document is to establish terminology, and create a framework for, and

provide guidance regarding the electrical performance of AC power simulators used to test

utility interactive photovoltaic (PV) power conversion equipment (PCE) for compliance with grid

interconnection standards.

It serves as a generalized guideline for the development of AC power simulators used within a

test and evaluation system for PV PCEs.

Testing laboratories are responsible for selecting the appropriate test items and procedures as

well as defining the required performance for adequate evaluation of utility interactive PV PCEs,

considering utility power requirements, local codes and regulations.

Utility interactive PCEs are used not only for PV, but also for various distributed generation

technologies such as wind power, battery energy storage, engine co-generation or fuel cells.

Some of the recommendations in this document may be similar and applicable for AC simulators

used to test these other generation technologies, but they are not intended to supersede testing

requirements found in related IEC standards.

This document may be used in conjunction with regional or national grid standards and codes,

such as:
a) European level utility interaction requirements such as:
EN 50549-1:2019,
EN 50549-2:2019.
b) German FGW TG3.
c) UL1741 supplement SA, SRD-UL-1741-SA-V1.1.
d) IEEE 1547-2003, IEEE1547a (Amendment 1) -2014 and IEEE1547.1-2005.
e) IEEE 1547-2018 and IEEE 1547.1-2020.
---------------------- Page: 8 ----------------------
IEC TS 63106-1:2020 © IEC 2020 – 7 –
SIMULATORS USED FOR TESTING OF PHOTOVOLTAIC POWER
CONVERSION EQUIPMENT – RECOMMENDATIONS –
Part 1: AC power simulators
1 Scope

The purpose of this part of IEC 63106 is to provide recommendations for Low Voltage (LV) AC

power simulators used for testing utility interactive photovoltaic power conversion equipment

(PCE).
NOTE Low Voltage refers to 1 000 Va.c. and less.

The AC power simulators connect to the AC output power port of a PCE under test and simulate

the utility grid by generating comparable AC voltage.

The AC power simulators can be used to test a PCE’s utility interaction characteristics, including

protection, ride through, immunity and power quality. The requirements and procedures are

specified in IEC standards and local utility grid requirements, selected by the network operator,

utility, or authority having jurisdiction.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes recommendations 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 61000-4-7:2002, Electromagnetic compatibility (EMC) – Part 4-7: Testing and

measurement techniques – General guide on harmonics and interharmonics measurements

and :instrumentation, for power supply systems and equipment connected thereto
IEC 61000-4-7:2002/AMD1:2008

IEC TS 61836:2016, Solar photovoltaic energy systems – Terms, definitions and symbols

IEC TS 62910:2020, Utility-interconnected photovoltaic inverters – Test procedure for under

voltage ride-through measurements

IEC TS 63106-2, Simulators used for testing of photovoltaic power conversion equipment –

recommendations – Part 2: DC power simulators

IEC TS 63217:– , Utility-interconnected photovoltaic (PV) inverters – Test procedure of high-

voltage ride-through measurements
3 Terms, definitions and abbreviated terms

For the purposes of this document, the terms and definitions given in IEC TS 61836 and the

following apply.
___________
Under preparation. Stage at the time of publication: ACD.
---------------------- Page: 9 ----------------------
– 8 – IEC TS 63106-1:2020 © IEC 2020

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
AC power simulator

system or device able to source and/or absorb AC power, for use in testing of PCE

Note 1 to entry: This document includes a real utility grid, where appropriate, as well as synthetic sources as

rotating machines or power converters.
3.2
power conversion equipment
PCE

electrical device converting one form of electrical power to another form of electrical power with

respect to voltage, current, frequency, phase and the number of phases
[SOURCE: IEC 62109-1:2010, 3.66]
3.3
port
particular interface of the PCE with external circuits
Note 1 to entry: see Figure 1 for examples of ports.
Figure 1 – Examples of ports
3.4
equipment under test
EUT
PCE that is tested by connecting and supplying DC and AC power to each port
3.5
AC output power port

port used to connect to a public low voltage AC mains power distribution network or other low

voltage AC mains installation
3.6
DC input power port

port used to connect the PCE to a low voltage DC photovoltaic power generating sub-system

3.7
distributed generation

decentralized power generation system that is connected to the utility grid in a distributed

manner
---------------------- Page: 10 ----------------------
IEC TS 63106-1:2020 © IEC 2020 – 9 –
3.8
low voltage
set of voltage levels used for the distribution of electricity
[SOURCE: IEC 60050-601:1985, 601-01-26, modified to delete upper limit voltage]
3.9
high voltage

set of upper voltage levels used in power system for bulk transmission of electricity

[SOURCE: IEC 60050-601:1985, 601-01-27]
3.10
medium voltage
any set of voltage levels lying between low and high voltage
[SOURCE: IEC 60050-601:1985, 601-01-28]
3.11
type test
conformity test made on one or more items representative of the production
[SOURCE: IEC 60050-151:2001, 151-16-16]
3.12
OVRT
over voltage ride through for utility failure durability of operation
3.13
UVRT
under voltage ride through for utility failure durability of operation
3.14
OFRT
over frequency ride through for utility failure durability of operation
3.15
UFRT
under frequency ride through for utility failure durability of operation
3.16
ROCOF
rate of change of power system frequency in Hz/s in the transient period
4 PCE types with respect to AC voltage levels and grid interconnection

In this document, utility interconnected voltage or capacity categories are not specified. PCE

based DG may be connected to the utility in any of the voltage ranges described below:

a) High voltage transmission or sub-transmission line connection.
b) Medium voltage distribution line connection.

c) Low voltage distribution line connection, including PCEs for residential use and micro

inverter or module integrated electronics.
---------------------- Page: 11 ----------------------
– 10 – IEC TS 63106-1:2020 © IEC 2020
Figure 2 shows examples of DG systems connected to the utility grid.
Figure 2 – Example of connection of DG systems to utility grid

Utility-interactive PCEs typically have AC voltage outputs in the range of 100 V to 1 000 V,

determined by the input DC voltage window of the PCE or the input voltage from a DC/DC

converter. Connections to the utility grid at higher voltages require the use of step-up

transformers. Therefore, an upper limit of 1 000 Va.c. for the AC voltage range of a PCE test

system is sufficient.
5 Test setup for utility interactive PCEs
5.1 General

In order to realize valid and reproducible testing, the AC power source shall be appropriate for

the test being performed. This may mean utilizing an actual power grid, an AC power generator

or an electronic AC power simulator depending on the needs of the specific test under

consideration. In this document, recommendations of AC power simulators for a wide range of

typical utility interconnection tests are described.

Similarly, the DC power source shall be appropriate for the test being performed. This may

mean utilizing an actual PV array output, a conventional power supply, or an electronic PV

power simulator depending on the needs of the specific test under consideration.
Recommendations for DC power simulators are addressed in IEC TS 63106-2.

NOTE Hardware in the loop (HIL) or software to control the voltage and frequency at the EUT output port point by

detecting output power (active and reactive) and calculating the voltage and frequency or phase properties by given

utility network model with simulated generators and line impedances are discussed and developed. They are not

used for type certification tests but still have potential usefulness in the future for testing the performance of multiple

DGs in combination with a smart grid.
---------------------- Page: 12 ----------------------
IEC TS 63106-1:2020 © IEC 2020 – 11 –
5.2 Test setup examples for utility interaction test
5.2.1 General

The test system shall be able to simulate steady state and transient utility grid conditions with

respect to AC voltage, frequency, line impedance, load, and other conditions as required for

the testing. Figure 3 illustrates basic configuration examples for the EUT test system. Here,

EUT is the utility interactive PV PCE under test. A DC power simulator is connected to the DC

input power port. An AC power simulator is connected to the AC output power port, with other

optional impedance and load equipment.

Figure 3 shows only the main power line connections to DC port, AC port in both sides. An earth

line may be shared between DC side and AC side devices.
Figure 3 – Examples of fundamental setup of EUT test system
5.2.2 Types of AC power simulator systems
5.2.2.1 General

AC power simulator systems may consist of one or more of the following types of equipment: in

5.2.2 through 5.2.4. Other approaches are possible depending on the test(s) under

consideration. As different tests have different power simulator needs, it may be required or

optional for a facility to have more than one type of AC power simulator.

The internal resistance of an AC power simulator including connections to the EUT so measured

at the EUT AC output power port should be designed referring the real-world distribution and

transmission line impedance, for attaining the reasonable test result for power qualities, as

harmonics, DC injection, or flicker tests.
---------------------- Page: 13 ----------------------
– 12 – IEC TS 63106-1:2020 © IEC 2020
5.2.2.2 Utility grid

A simple utility grid connection may be used for certain tests. The utility grid used shall have

the right nominal voltage and frequency, appropriate impedance and harmonic distortion levels,

and the ability to source or sink adequate active or reactive power for the test(s) under

consideration.
5.2.2.3 Utility grid and transformer with tap changer

A transformer with tap changer can change the output voltage of the AC power simulator but

only in discrete steps. Some types can be switched under load while others require the

transformer to be de-energized before switching. Quick transfer of voltage is realized by using

a semiconductor switch for the tap changer. Some types will cause a momentary loss of voltage

to the EUT while others do not. These characteristics need to be taken into account when

considering this technique for an AC power simulator.
5.2.2.4 Electronic AC power simulator

An electronic AC power simulator uses power electronics to create or modify AC grid voltage.

Electronic AC power simulators may be composed of an AC to DC conversion stage followed

by a DC to AC conversion stage. Other approaches such as waveform simulation with power

amplification are possible. Electronic AC power simulators provide a wide range of capabilities

for testing including continuous control of the output AC voltage, phase, and frequency. The

electronic AC power simulator provides testing voltage conditions for voltage swells (OVRT)

and sag (UVRT) on 1,2 or all 3 phases, and for some types, arbitrary waveform generation. The

electronic AC power simulator provides testing frequency conditions for frequency rise (OFRT)

and frequency drop (UFRT).

Electronic AC power simulators are typically categorized for three different product groups

based on size, including micro PCE, string PCE and central PCE. The fundamental output

characteristics of the electronic AC power simulators may depend on the testing power level

and the control of switching devices and circuits. For small scale PCE’s testing, linear power

amplification configurations are well-suited for precise output voltage control. For large scale

applications, chopper circuits with bi-directional control are typically used to reduce heat

dissipation. For a back-to-back system consisting of a chopper converter and inverter circuit

configuration, the output voltage harmonic distortion components are absorbed with sufficient

AC filter circuit.
5.2.2.5 Rotating engine and AC power generator

A rotating engine coupled to an AC power generator provides a controllable source isolated

from the utility grid. This provides a source independent of utility grid conditions and able to be

used at remote sites of PV installations in addition to laboratories. Motor-driven generator

systems are capable of continuous control of AC voltage and frequency. Such systems are

limited to creating only symmetrical variations (all three phases vary in the same manner).

5.2.3 Load
5.2.3.1 General

For some testing, it is required or important to control the impedance as seen by the EUT. This

can be inherent impedance of the AC power simulator, or additional local active or reactive

loads or line impedances may be needed.
5.2.3.2 Inherent impedance
All types of AC power simulators have an inherent impedance as seen by
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.