IEC TS 63102:2021

IEC TS 63102 ®
Edition 1.0 2021-09
TECHNICAL
SPECIFICATION
colour
inside
Grid code compliance assessment methods for grid connection of wind and PV
power plants
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IEC TS 63102 ®
Edition 1.0 2021-09
TECHNICAL
SPECIFICATION
colour
inside
Grid code compliance assessment methods for grid connection of wind and PV

power plants
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160; 27.180 ISBN 978-2-8322-1022-1

– 2 – IEC TS 63102:2021  IEC 2021
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, abbreviations and subscripts . 7
3.1 Terms and definitions . 7
3.2 Abbreviations and subscripts . 8
3.2.1 Abbreviations . 8
3.2.2 Subscripts . 9
4 Symbols and units . 9
5 General specifications . 10
5.1 General . 10
5.2 Type tested units – Wind turbines and PV inverters . 10
5.3 Projects – Wind and PV power plants . 10
5.4 Compliance assessment methods . 10
6 Operating area . 11
6.1 General . 11
6.2 Frequency range . 11
6.2.1 Documentation . 11
6.2.2 Method 1: Monitoring . 11
6.3 Voltage range . 12
6.3.1 Documentation . 12
6.3.2 Method 1: Simulation . 12
6.3.3 Method 2: Monitoring . 12
6.4 Reactive power capability . 12
6.4.1 Documentation . 12
6.4.2 Method 1: Simulation . 12
6.4.3 Method 2: Monitoring . 13
7 Control performance . 13
7.1 General . 13
7.2 Active power based control . 13
7.2.1 Documentation . 13
7.2.2 Method 1: Plant field testing . 14
7.2.3 Method 2: Monitoring . 17
7.2.4 Method 3: CHIL testing . 17
7.3 Reactive power based control . 19
7.3.1 Documentation . 19
7.3.2 Method 1: Plant field testing . 20
7.3.3 Method 2: Monitoring . 23
7.3.4 Method 3: CHIL testing . 23
8 Fault ride through . 24
8.1 General . 24
8.2 Documentation . 24
8.3 Method 1: Simulation . 25
8.4 Method 2: Monitoring . 27
9 Power quality . 28
9.1 General . 28

9.2 Current harmonics and inter-harmonics . 28
9.2.1 Documentation . 28
9.2.2 Method 1: Plant Field testing . 28
9.3 Flicker . 29
9.3.1 Documentation . 29
9.3.2 Method 1: Plant field testing . 29
Annex A (informative) Monitoring of electrical performance of wind and PV power
plants. 30
A.1 Overview. 30
A.2 Responsibilities . 30
A.3 Basic principles . 30
A.4 Monitoring signals . 30
A.5 Monitoring hardware . 31
Annex B (informative) Controller hardware in the loop (CHIL) testing setup . 32
B.1 General . 32
B.2 Power plant modelling . 32
B.3 Set-up . 32
Annex C (informative) Harmonic simulation for wind and PV power plants . 34
C.1 General . 34
C.2 General simulation methods . 35
Annex D (informative) Control performance index . 37
Bibliography . 38

Figure 1 – An example of PQ diagram . 13
Figure 2 – Example of figure for active power ramp rate test . 15
Figure 3 – Example of figure for set point test of active power . 15
Figure 4 – Example of figure for frequency control test . 16
Figure 5 – Example of figure for frequency control test with simulated frequency
variation . 18
Figure 6 – Example figure for set point control of reactive power as control reference
(reactive power control mode) . 21
Figure 7 – Example of figure for set point control of voltage as control reference
(voltage control mode) . 22
Figure 8 – Example of figure for voltage control test . 23
Figure 9 – Layout of grid with symmetrical fault . 25
Figure 10 – Layout of grid with unsymmetrical fault . 25
Figure 11 – Example of active power recovery . 27
Figure 12 – Equivalent circuit of the grid and the power plant . 29
Figure B.1 – Test bench diagram . 33
Figure C.1 – Ideal harmonic current source illustration for harmonic distortion
calculation . 34
Figure C.2 – Converter harmonic model as a Norton/Thevenin equivalent circuit . 35
Figure C.3 – Norton equivalent harmonic current source illustration for network
harmonic distortion calculation . 35
Figure C.4 – Power electronics average model Norton equivalent circuit representation . 36
Figure D.1 – Performance index of active and reactive power based control . 37

– 4 – IEC TS 63102:2021  IEC 2021
Table 1 – Overview of assessment methods . 11
Table 2 – Example table for maximum variation value of active power . 16
Table 3 – Example of table for performance index of set point test. 17
Table 4 – Example of table for performance index of frequency control response . 17
Table 5 – Example of table for functionality test of frequency control . 19
Table 6 – Example of table for coordination functionality of active power set point and
frequency control . 19
Table 7 – Example of table for reactive power control testing . 22
Table 8 – Example of table for voltage control testing . 23
Table 9 – Example of table for voltage control test . 24
Table 10 – Recommended scenario of pre-fault operation modes . 26
Table 11 – Recommended scenario of grid fault types and under/over voltage levels . 26
Table 12 – Example table for fault ride through simulation results . 27
Table A.1 – Monitoring signals . 31
Table B.1 – CHIL system boundaries . 33
Table B.2 – Signal list . 33

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
GRID CODE COMPLIANCE ASSESSMENT METHODS FOR GRID
CONNECTION OF WIND AND PV POWER PLANTS

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
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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.
IEC TS 63102 has been prepared by subcommittee SC 8A: Grid integration of renewable
energy generation, of IEC technical committee TC 8: System aspects of electrical energy
supply. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
8A/80/DTS 8A/86/RVDTS
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 Technical Specification is English.

– 6 – IEC TS 63102:2021  IEC 2021
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/standardsdev/publications.
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,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates that it
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GRID CODE COMPLIANCE ASSESSMENT METHODS FOR GRID
CONNECTION OF WIND AND PV POWER PLANTS

1 Scope
This technical specification highlights recommended technical methods of grid code
compliance assessment for grid connection of wind and PV power plants as the basic
components of grid connection evaluation. The electrical behaviour of wind and PV power
plants in this technical specification includes frequency and voltage range, reactive power
capability, control performance including active power based control and reactive power
based control, fault ride through capability and power quality.
Compliance assessment is the process of determining whether the electrical behaviour of
wind and PV power plants meets specific technical requirements in grid codes or technical
regulations. The assessment methods include compliance testing, compliance simulation and
compliance monitoring. The input for compliance assessment includes relevant supporting
documents, testing results and validated simulation models, and continuous monitoring data.
The scope of this technical specification only covers assessment methods from a technical
aspect; processes related to certification are not included.
This technical specification is applicable to wind and PV power plants connected to the
electrical power grid.
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 60050-415:1999, International Electrotechnical Vocabulary – Part 415: Wind turbine
generator systems
IEC 61400-21-1, Wind energy generation systems – Part 21-1: Measurement and assessment
of electrical characteristics – Wind turbines
IEC 62934, Grid integration of renewable energy generation – Terms and definitions
3 Terms, definitions, abbreviations and subscripts
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61400-21-1,
IEC 60050-415, IEC 62934 and the following apply.
ISO and IEC also maintain terminological database 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

– 8 – IEC TS 63102:2021  IEC 2021
3.1.1
compliance monitoring
monitoring activity with the purpose of demonstrating the continuous compliance with the
required specifications throughout the lifetime of the power plant
3.1.2
compliance simulation
simulation activity with the purpose of demonstrating the compliance with the required
specifications, especially where testing is not applicable or risk of damaging the facility exists
3.1.3
controller hardware in the loop testing
CHIL testing
testing method for the subject controller based on physical and digital real-time simulation
Note 1 to entry: A simulation model is used to build the external real-time testing environment. Then a closed loop
test system is composed of the simulation model and embedded physical controller under test.
3.1.4
grid code
document that recommends practices or procedures for the activities of connection,
management, planning, development and maintenance of the electrical transmission and
distribution grid, as well as dispatching and metering, etc.
3.1.5
grid code compliance
demonstration that the electrical behaviours of power plants satisfy specific technical
requirements in grid codes or technical regulations
3.2 Abbreviations and subscripts
3.2.1 Abbreviations
The following abbreviations are used in this document:
CHIL controller hardware in the loop
CIGRE International Council on Large Electric Systems
CT Current Transformer
DB Dead Band
FACTS Flexible Alternating Current Transmission Systems
HVDC High Voltage Direct Current
OF Over Frequency
OVRT over-voltage ride-through
PCS power conditioning system
PV photovoltaic
POC point of connection
PQ active power and reactive power
SCR short circuit ratio
STATCOM static synchronous compensator
TS technical specification
UF Under Frequency
UVRT under-voltage ride-through
VT Voltage Transformer
3.2.2 Subscripts
F fault
meas measured value
max maximum
min minimum
n nominal
Omax maximum value of over voltage fault
poc-s produced by the grid
poc-c produced by the power plant
ref reference value
s variable of grid
sa phase A of grid
sb phase B of grid
sc phase C of grid
Umin minimum value of under voltage fault
4 Symbols and units
In this document, the following symbols and units are used.
I tested results of the current at POC (A)
poc
I harmonic currents produced by the grid (A)
poc-s
I harmonic currents produced by the power plant (A)
poc-c
I equivalent current of the grid
s
I equivalent current of the plant
c
P active power of the power plant (W)
P active power rated value (W)
n
P active power measured value (pu)
meas
P maximum long-term flicker
lt
P maximum background long-term flicker
lt0
P maximum long-term flicker caused by power plant
ltRE
Q reactive power of the power plant (Var)
Q reactive power reference value (pu)
ref
Q reactive power measured value (pu)
meas
Q maximum reactive power at POC (Var)
max
Q minimum reactive power at POC (Var)
min
S short circuit power (VA)
k
U rated value of voltage at POC (V)
n
U voltage of the grid (V)
s
U phase A voltage of the grid (V)
sa
U phase B voltage of the grid (V)
sb
U phase C voltage of the grid (V)
sc
U maximum voltage under normal operation at POC (V)
max
U minimum voltage under normal operation at POC (V)
min
– 10 – IEC TS 63102:2021  IEC 2021
U minimum value under voltage according to gird codes (V)
Umin
U maximum value over voltage according to gird codes (V)
Omax
U tested results of the voltage at POC (V)
poc
Z equivalent impedance of the power plant (Ω)
c
Z equivalent fault impedance (Ω)
F
Z equivalent impedance of the grid (Ω)
s
Z phase A equivalent impedance of the grid (Ω)
sa
Z phase B equivalent impedance of the grid (Ω)
sb
Z phase C equivalent impedance of the grid (Ω)
sc
5 General specifications
5.1 General
Technical requirements of wind and PV power plants for connecting to the grid were given in
the grid codes, such as operating area, active power control, reactive power control, fault ride
through, etc. Some existing IEC standards like IEC 61400-21 (all parts) and IEC 61400-27 (all
parts) specify the measurement procedures, modelling and validation methods of electrical
characteristics for wind turbines and wind power plants. This technical specification will
specify the compliance assessment methods of the electrical behaviours stipulated in the grid
codes.
5.2 Type tested units – Wind turbines and PV inverters
Type tested units are a series of wind turbines or PV inverters that have a common design,
materials and major components, subject to a common manufacturing process and uniquely
described by specific values or ranges of values of machine parameters and design
conditions. The definition of a type tested unit is dependent on the characteristics being
assessed and should be agreed by all stakeholders. Type testing is usually performed only
once per type in order to prove the general capability for all units of this type.
5.3 Projects – Wind and PV power plants
Wind or PV power plants are usually built clustering many units and jointly connecting them to
the grid. For these, a project based assessment needs to be performed. This means using
results from the type tested assessment, but taking the site-specific parameters into account.
5.4 Compliance assessment methods
In general, methods of project based compliance assessment can be classified into three
general categories:
• testing, including field testing and controller hardware in the loop (CHIL) testing;
• simulation;
• monitoring.
NOTE Annex A includes detailed information and recommendations for monitoring.
Normally for each electrical behaviour there is more than one compliance assessment method.
The selection of assessment methods should be carried out by system operators taking into
consideration the following factors:
• the technology of the project, including whether the performance is likely to drift or
degrade over a particular time-frame;
• experience with the particular generation technology, including manufacturer's advice;
• the connection point arrangement;

• an assessment of the risks and costs of different testing methods, including consideration
of the relative size of the plant;
• the availability and location of testing equipment, monitoring/metering equipment and
other necessary facilities.
Table 1 gives an overview of recommended assessment methods for different electrical
behaviors.
Table 1 – Overview of assessment methods
Field testing CHIL Simulation Monitoring
Frequency
x
range
Operating area Voltage range  x x
Reactive power
x x
capability
Control performance x x x
Fault ride through  x x
Power quality x
x: recommended assessment methods.

6 Operating area
6.1 General
As the frequency and voltage of the power system are not constant, the wind and PV power
plants need to be capable of being operated continuously or for certain durations within
specified frequency and voltage ranges required by the grid codes. Reactive power capability
is also required to help maintain the system voltage and fulfil reactive power demand of the
grid. The operating area is generally focused on steady state conditions. For compliance
assessment of transient behaviour during grid faults, see Clause 8.
Assessment of the operating area is the assessment of appropriate equipment rating. This
rating assessment for power plants should be based on the units and the additional
equipment installed in the plant. This assessment can be undertaken in the planning phase
based on related documentation and load flow simulations. The continuous compliance should
be monitored as well. Field testing at the wind or PV power plant level is not recommended for
confirmation of the entire frequency and voltage area since this testing can endanger both
grid and plant safety. However, field testing could be conducted to confirm reactive power
capability and a limited range within the frequency or voltage area.
6.2 Frequency range
6.2.1 Documentation
Related documentation should be provided in the planning phase declaring the frequency
range of units and additional equipment installed in the power plant. For the units and
additional equipment, specification or manufacturer declarations should be submitted.
6.2.2 Method 1: Monitoring
The POC of the power plant and main equipment within the plant should be monitored and
assessed continuously. For the evaluation of power plant operability with decreased or
increased grid frequency, the protection settings at POC should be documented.

– 12 – IEC TS 63102:2021  IEC 2021
6.3 Voltage range
6.3.1 Documentation
Corresponding documentation should be provided in order to prove the voltage operational
range of units and additional equipment are installed in the power plant. For each component
under assessment, specification or manufacturer declarations should be submitted.
For additional equipment installed in the power plant, documentation of those components
should be provided. Documentation may include, but should not be limited to rating plate data,
environmental assumptions and corresponding calculations.
6.3.2 Method 1: Simulation
The voltage range of power plants is referred to the POC. All terminals of the units and main
equipment within the plant should be assessed (e.g. transformers, reactive power
compensation devices). This can be achieved by load flow simulation, during which
corresponding assumptions should be made for the worst realistic cases at all terminals.
Dynamic simulation (with base frequency domain 50 Hz/60 Hz RMS simulation) can help
confirm the withstand time of wind and PV power plants capability to voltages in the voltage
area. Modelling and model validation procedure can refer to IEC 61400-27-1 and
IEC 61400-27-2.
6.3.3 Method 2: Monitoring
The POC of the power plant and main equipment within the plant should be monitored and
assessed continuously. For the evaluation of power plant operability with decreased or
increased grid voltage, the protection settings at POC should be documented.
6.4 Reactive power capability
6.4.1 Documentation
For wind power plants, tests for reactive power capability should be performed for each type
of wind turbine according to IEC 61400-21-1. When each PCS device is individually equipped
with a voltage detection device and reactive power control function, it is sufficient to perform a
verification test for that function at the manufacturer's factory or testing laboratory, making
field testing optional. Alternatively, corresponding type test reports can be assessed if they
have been performed in the past. The scope of required testing depends on grid codes. If no
type tests exist, corresponding tests should be performed instead.
If the plant contains reactive power compensation devices, corresponding documentation
should be provided declaring their reactive power capability. For STATCOM, the available
operation modes should be listed and clarified in detail. Corresponding type test reports,
specification or manufacturer declarations should be submitted.
6.4.2 Method 1: Simulation
Before simulation, the reactive power capability of unit models should be configured according
to IEC 61400-27-1 based on type testing results. The maximum and minimum reactive power
capability of the power plant should be verified with load flow calculations, which are
determined by the capability of the units and other components like cables, transformers and
compensation devices.
Simulation procedure of maximum reactive power capability:
• Set all units to the appropriate control mode with the reference value equal to the
maximum operation voltage, or set all units to reactive power control mode with the
reference values equal to the maximum reactive power.
• Execute a sequence of load flow simulations with varying active power levels.

Simulation procedure of minimum reactive power capability:
• Set all units to the appropriate control mode with the reference value equal to the
minimum operation voltage, or set all units to reactive power control mode with the
reference values equal to the minimum reactive power.
• Execute a sequence of load flow simulations with varying active power levels.
The maximum and minimum operation voltage is based on the voltage range of continuous
operation in 6.3. For low active power level (e.g. P < 10 %P ), if reactive power capability
n
were not required in grid codes, then relevant simulation scenarios are not mandatory. The
simulation results can be summarized as a PQ-diagram including both the grid code
requirements and the plant capability (see Figure 1 as an example).

Figure 1 – An example of PQ diagram
6.4.3 Method 2: Monitoring
The reactive power at the plant POC should be monitored and assessed continuously.
7 Control performance
7.1 General
Grid codes require power plants to be properly controlled keeping power systems in balance
and stable condition. Depending on grid codes, the active power outputs of power plants
could be controlled by either active power or grid frequency variation settings. This kind of
control performance is named active power based control. Meanwhile the control reference of
reactive power could be selected from either reactive power, grid voltage or power factor
settings, and the related control performance is named reactive power based control.
Control performance assessment intends to assess the functionality and controllability of
plants in both normal and dynamic operation states. The electrical behaviour can be directly
tested in pre-commercial operation phase if permitted by system operators. Some special test
cases should be performed by CHIL, due to the unchangeable grid frequency and safe range
of voltage. The control performance of power plants can also be assessed and monitored
during commercial operation.
7.2 Active power based control
7.2.1 Documentation
Specification or manufacturer declarations of plant controllers should be submitted.

– 14 – IEC TS 63102:2021  IEC 2021
7.2.2 Method 1: Plant field testing
The active power at POC can be measured with variant control references such as set point
and ramp rate. In order to assess frequency control performance, variant frequency signals
can be injected into the plant controller to simulate a grid frequency incident. During plant
field testing the injected system frequency should be manipulated within certain frequency
operation range according to grid codes, normally including Under-Frequency (UF) range,
Dead-Band (DB) range, and Over-Frequency (OF) range. The testing procedure should refer
to IEC 61400-21-2 .
Plant field testing should meet the following conditions:
• The available active power output of power plant should be at least 50 % of rated power.
• The plant active power production at POC and control reference signal should be
monitored and documented continuously at the same time.
• The plant active power production, grid frequency at POC and control reference signal
should be monitored and documented at the same time, when the frequency control is
performed.
• If a grid meter is used for the measurement, the sampling frequency of grid meter output
should be at least 10 Hz.
• If no grid meter is used, the measurements should be obtained by CT/VT sensors, and the
sampling frequency of measurements should be at least 1 kHz.
• During a field test, all measurements signals should be time stamped, in order to assess
the plant control timing related performance, for instance, rise time.
• The testing results should be reported as 0,1 s average data.
The contents of plant field testing include:
• active power ramp rate test;
• active power set point test;
• frequency control test (variant frequency signals injected into the plant controller to
simulate a grid frequency incident).
Results of plant field testing should be presented in the following form:
• Figure: time series of active power set point value and measured active power output in
the ramp rate test, see Figure 2.
• Figure: time series of control reference and measured active power output in the set point
test, see Figure 3.
• Figure: time series of adjustment response of injected frequency test, see Figure 4.
____________
Under preparation. Stage at the time of publication: IEC/CCDV 61400-21-2:2021.

Figure 2 – Example of figure for active power ramp rate test

Figure 3 – Example of figure for set point test of active power

– 16 – IEC TS 63102:2021  IEC 2021

Figure 4 – Example of figure for frequency control test
• Table: Maximum variation value in 10 min and 1 min of active power in the ramp rate test,
see Table 2. It can be calculated by using sliding window in the test data.
• Table: Control settling time, overshoot as percentage of reference and static error for each
control reference in the set point test, see Table 3. The calculation method of performance
index described in Annex D.
• Table: Control response time, control settling time, active power before and after the
injected frequency disturbance and static error in the frequency control test, see Table 4.
Performance indexes are described in Annex D.
The performance index and cases for compliance assessment listed in Table 2~Table 4
should be determined according to the situation in different countries.
Table 2 – Example table for maximum variation value of active power
Maximum variation value in 10 min Maximum variation value in 1 min
Cases
(MW) (MW)
Normal operation
Start-up
Stop
Table 3 – Example of table for performance index of set point test
Set value of active power
Control settling time Overshoot Tolerance band
(s) (%) (%)
[(P/P ) p.u.]
n
0,8 → 0,6
0,6 → 0,4
0,4 → 0,2
0,2 → 0,4
0,4 → 0,6
0,6 → 0,8
Table 4 – Example of table for performance index of frequency control response
Cases Control Control Active power Active power Tolerance
response settling time before after band
time disturbance disturbance
(s) (%)
(s)
(p.u.) (p.u.)
50 Hz → 50,2 Hz
(Active power derating to
0,2 p.u ~ 0,3 p.u.)
50 Hz → 50,2 Hz
(Active power
0,2 p.u ~ 0,3 p.u. without
derating)
50 Hz → 50,2 Hz
(Active power derating to
0.5~0.9 p.u.)
50 Hz → 50,2 Hz
( Active power 0.5~0.9p.u.
without derating)
50 Hz → 49,8 Hz
(Active power derating to
0.2 p.u ~ 0.3 p.u.)
50 Hz →49,8 Hz
( Active power
0.2 p.u. ~ 0.3 p.u. without
derating)
7.2.3 Method 2: Monitoring
The plant active power production at POC should be measured, while the control reference
signal should be monitored continuously at the same time.
If frequency control is required, the plant frequency at POC should be measured
simultaneously, while the control reference signal should be monitored continuously at the
same time.
7.2.4 Method 3: CHIL testing
CHIL is generally used for active power based control strategy testing. In CHIL testing
environment, the plant controller should be hardware based. Except that, the power plant
should be a simulation model with at least one generation unit, as well as the external grid.
The testing procedure can refer to IEC 61400-21-2.

– 18 – IEC TS 63102:2021  IEC 2021
CHIL testing should meet following conditions:
• The available active power output of the power plant should be equal to the rated power.
• Simulated frequency variation (upward and downward) should be obtained in the external
grid model.
• The testing results should be reported as 0,1 s average data.
The contents of CHIL testing include:
• frequency control functionality;
• coordination functionality of active power set point and frequency control.
Results of CHIL test should be presented in the following form:
• Figure: Time series of simulated frequency variation, active power reference and
measured active power output, see Figure 5.

Figure 5 – Example of figure for frequency control
test with simulated frequency variation
• Table: functionality assessment of frequency control, see Table 4.
• Table: frequency step value, active power set point and measured active power output in
the coordin
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