IEC TS 63427:2026

IEC TS 63427 ®
Edition 1.0 2026-06
TECHNICAL
SPECIFICATION
Guidelines for the adjustment potential evaluation of demand side resources
ICS 91.140.50; 27.015 ISBN 978-2-8327-1311-2
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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms and definitions . 6
4 General . 9
5 DSR characteristics . 9
5.1 Availability window . 9
5.2 Response time . 9
5.3 Service duration . 10
5.4 Service capacity . 10
5.5 Adjustment rate . 10
5.6 Adjustment accuracy . 11
5.7 Reverse load rate of PCC . 11
5.8 Service capacity utilization rate . 12
5.9 DSR characteristics in generation mode and consumption mode . 13
6 System requirements of different applications . 13
6.1 System requirements . 13
6.2 Application requirements. 14
6.2.1 Peak-load shifting . 14
6.2.2 Frequency regulation . 15
6.2.3 Voltage regulation . 16
6.2.4 Congestion management . 17
6.3 Evaluation indices for different applications . 19
7 Evaluation process . 19
7.1 Data preparation . 19
7.1.1 Data objects . 19
7.1.2 Data acquisition . 20
7.2 Evaluation method . 20
Annex A (informative) Recommended sources and uses of data necessary for DSR
adjustment potential evaluation . 22
Annex B (informative) Evaluation indices of DSR unit at different applications . 24
Annex C (informative) DSR unit adjustment potential grading . 26
Bibliography . 27

Figure 1 – Schematic view of DSR unit connected to distribution network . 7
Figure 2 – Schematic diagram of service capacity utilization rate . 12
Figure 3 – DSR characteristics in generation mode . 13
Figure 4 – DSR characteristics in consumption mode . 13
Figure 5 – System requirements of peak-load shifting . 14
Figure 6 – Example of DSR evaluation indices for peak-load shifting . 15
Figure 7 – System requirements of frequency regulation . 16
Figure 8 – Example of DSR evaluation indices for frequency regulation . 16
Figure 9 – System requirements of voltage regulation . 17
Figure 10 – Example of DSR evaluation indices for voltage regulation . 17
Figure 11 – System requirements of congestion management . 18
Figure 12 – Example of DSR evaluation indices for congestion management . 18
Figure 13 – Evaluation method . 21

Table 1 – Recommended evaluation indices for different applications . 19
Table A.1 – Data necessary for DSR adjustment potential evaluation . 22
Table B.1 – Evaluation indices for peak-load shifting . 24
Table B.2 – Evaluation indices for frequency regulation . 24
Table B.3 – Evaluation indices for voltage regulation . 25
Table B.4 – Evaluation indices for congestion management . 25
Table C.1 – Adjustment potential grading for peak-load shifting . 26
Table C.2 – Adjustment potential grading for frequency regulation . 26
Table C.3 – Adjustment potential grading for voltage regulation . 26
Table C.4 – Adjustment potential grading for congestion management . 26

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Guidelines for the adjustment potential evaluation
of demand side resources
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
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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
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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.
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shall not be held responsible for identifying any or all such patent rights.
IEC TS 63427 has been prepared by subcommittee 8B: Decentralized electrical energy systems,
of IEC technical committee 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
8B/283/DTS 8B/295/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.
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.
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.
INTRODUCTION
With the increase of dispatchable loads, electric vehicles, distributed energy resources, and
microgrids, demand side resources (DSR) are expected to have more interactions with, and
provide support to, the electric power networks. The utilization of DSR requires a
comprehensive consideration of its physical characteristics, user behaviour, willingness to
participate, and market conditions, etc. This document only considers the physical
characteristics of DSR in the evaluation of its adjustment potential.
This document provides an evaluation method of DSR adjustment potential and specifies the
evaluation indices for different applications. The objects of DSR adjustment potential evaluation
focus on the aggregated characteristics of DSR units for various stakeholders, such as users
participating in demand response, DSR aggregators, virtual power plant (VPP) owners and
operators, and distribution system operators (DSOs).

1 Scope
This document provides principles and technical requirements for the adjustment potential of
demand side resources in demand side management. Demand side resources include
dispatchable loads, electrical energy storage, grid-connected microgrids, and distributed
energy resources, which are connected to power distribution systems and capable of adjusting
their operating state and exchanging information with grid control systems. It includes the DSR
characteristics, system requirements, data preparation and evaluation process.
The adjustments of demand side resources can be subject to relevant local regulations or
specifications. Electricity market mechanisms, user behaviour and data privacy are excluded
from the scope of this document.
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 63189-1:2023, Virtual power plants - Part 1: Architecture and functional requirements
IEC TS 63276, Guidelines for the hosting capacity evaluation of distribution networks for
distributed energy resources
IEC 62351-3, Power systems management and associated information exchange - Data and
communications security - Part 3: Communication network and system security - Profiles
including TCP/IP
IEC 62351-5, Power systems management and associated information exchange - Data and
communications security - Part 5: Security for IEC 60870-5 and derivatives
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
demand side management
DSM
process that is intended to influence the quantity or patterns of use of electric energy consumed
by end-use customers
[SOURCE: IEC 60050-617:2011 [2], 617-04-15]
3.2
point of connection
POC
reference point on the distribution network where the user's electrical facility is connected
[SOURCE: IEC 60050-617:2009 [2], 617-04-01, modified - replaced "electric power system"
with "distribution network"]
3.3
point of common coupling
PCC
point in an electric power system, electrically nearest to a particular load, at which other loads
are, or may be, connected
Note 1 to entry: These loads can be either devices, equipment or systems, or distinct network users' installations.
[SOURCE: IEC 60050-161:1990 [3], 161-07-15]
3.4
demand side resources unit
DSR unit
group of DSR equipment/system, including dispatchable loads, controllable loads, electrical
energy storage, grid-connected microgrids, distributed energy resources, connected to one
PCC/POC and which provides flexibility support to the power grid

Figure 1 – Schematic view of DSR unit connected to distribution network
SEE: Figure 1.
Note 1 to entry: Demand side resources can react to demand response events and market price signals, and
automatically or passively adjust their operating status, including dispatchable loads, controllable loads, electrical
energy storage, distributed energy resources (DER).
3.5
adjustment potential
ability of a demand side resource unit to change its active power, including physical and
technical adjustment potential
Note 1 to entry: Physical adjustment potential is defined as the maximum active power of a load or the maximum
active power output of a distributed generator.
Note 2 to entry: Technical adjustment potential is defined as the active power that can be adjusted with the current
technical settings, including current operation point settings, communication conditions, etc.
3.6
distribution system operator
DSO
party operating a distribution network
Note 1 to entry: In some countries, a DSO is also referred to as DNO (distribution network operator).
[SOURCE: IEC TS 62786-1:2023 [8], 3.1.6]
3.7
dispatchable load
load for which the active power consumption can be modified while maintaining the functionality
of that load within an acceptable range of parameters
Note 1 to entry: Maintaining the load's functionality is often achieved by use of an internal energy storage.
Note 2 to entry: The use of dispatchability depends on an agreement between grid user and grid operator.
Note 3 to entry: The feature of dispatchability can be made accessible either by self-regulation or remote control.
Note 4 to entry: The reference point for the conformity assessment is the terminal of the load.
[SOURCE: IEC TS 62898-3-3:2023 [9], 3.1.7]
3.8
distributed energy resources, pl
DER, pl
generators (with their auxiliaries, protection and connection equipment), including loads having
a generating mode (such as electrical energy storage systems), connected to a low-voltage or
a medium-voltage network
[SOURCE: IEC 60050-617:2017 [2], 617-04-20]
3.9
controllable load
load of particular consumers which under contract must be increased or reduced within the
established limits, for a limited period of time, at the request of the distribution supply
undertaking
Note 1 to entry: Controllable load can be increased as well as reduced, according to the request of the distribution
supply undertaking.
[SOURCE: IEC TS 63189-1:2023, 3.1]
3.10
prosumer
network user that consumes and produces electrical energy
[SOURCE: IEC 60050-617:2017 [2], 617-02-16]
3.11
aggregator
party who contracts with a number of other network users (e.g. energy consumers) in order to
achieve combined effect of smaller loads or distributed energy resources for actions such as
demand response or for ancillary services
[SOURCE: IEC 60050-617:2017 [2], 617-02-18]
3.12
system operator
SO
party responsible for safe and reliable operation of a part of the electric power system in a
certain area and for connection to other parts of the electric power system
[SOURCE: IEC 60050-617:2009 [2], 617-02-09]
3.13
congestion
situation in a transmission or distribution network requiring, in parts of an electric power system,
a limitation of load flow
[SOURCE: IEC 60050-617:2009 [2], 617-03-04, modified – the note has been removed.]
4 General
The DSR unit has its own physical characteristics determined by the type of equipment, capacity,
technology, etc. The utilization of DSR depends on whether the physical characteristics of DSR
can match the requirements of the power system. To enable the evaluation of whether and to
what extent the DSR can match the requirements, the physical characteristics of DSR are
described through a series of evaluation indices in Clause 5, including availability window,
response time, service duration, service capacity, adjustment rate, adjustment accuracy,
reverse load rate of PCC, and service capacity utilization rate. The response time, service
duration, service capacity, adjustment rate, and adjustment accuracy should comply with
IEC TS 63189–1, while the reverse load rate of PCC should comply with IEC TS 63276.
Based on power system operation requirements, the utilization of demand side resources
applications is categorized as peak-load shifting, frequency regulation, voltage regulation, and
congestion management. For different applications, some of the evaluation indices are more
important, which determine whether the DSR can be used. Such evaluation indices are
described as core indices. Only if these evaluation indices meet the system requirements, then
other evaluation indices, described as additional evaluation indices, can be used to select a
more suitable DSR for certain application. Clause 6 specifies the system requirements of the
applications, and the corresponding core and additional evaluation indices.
5 DSR characteristics
5.1 Availability window
The availability window is the time period declared by the DSR owner when the resources
should be available to provide service. The availability window (e.g. per hour, per day, per week,
per year) should be specified based on market mechanisms.
5.2 Response time
The response time is the time duration from the time that the DSR unit receives the action
instruction to the time that the output power of the DSR unit reaches the target power range for
the first time. The target power range is defined based on practical application, for example 90 %
of the target power.
T tt−
(1)
re S ins
where
T is the response time;
re
t is the time that the output power of the DSR unit reaches the target power range for the
S
first time;
t is the time that the DSR unit receives the action instruction.
ins
NOTE The output power of the DSR unit can be positive or negative.
5.3 Service duration
The service duration is the time duration from the time that the output power of the DSR unit
reaches the target power range for the first time to the time that the output power of the DSR
unit exceeds the target power range for the first time and remains outside the range.

ΔT t−t
(2)
ES
where
is the service duration;
∆T
t is the time that the output power of the DSR unit exceeds the target power range for the
E
first time and remains outside the range;
t is the time that the output power of the DSR unit reaches the target power range for the
S
first time.
NOTE The specified range for power deviation will be set according to the actual local conditions.
5.4 Service capacity
The service capacity refers to the difference between the maximum and minimum output power
that a DSR unit can adjust to in responding to DSM instructions.
5.5 Adjustment rate
The adjustment rate refers to the percentage of the single-direction power change per minute
relative to the service capacity.
∆L
K ×100%
(3)
P
N
where
K is the adjustment rate, expressed in percentage per minute (%/min);
∆L is the single-direction power change per minute, expressed in kilowatts per minute
(kW/min);
is the service capacity.
P
N
=
=
=
5.6 Adjustment accuracy
The adjustment accuracy is the difference between the output power of the DSR unit and
K
...