IEC TS 62898-3-4:2023

IEC TS 62898-3-4
®

Edition 1.0 2023-08
TECHNICAL
SPECIFICATION



Microgrids –
Part 3-4: Technical requirements – Microgrid monitoring and control systems

IEC TS 62898-3-4:2023-08(en)

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IEC TS 62898-3-4

®


Edition 1.0 2023-08




TECHNICAL



SPECIFICATION



















Microgrids –

Part 3-4: Technical requirements – Microgrid monitoring and control systems


























INTERNATIONAL

ELECTROTECHNICAL


COMMISSION





ICS 29.240.01  ISBN 978-2-8322-7438-5




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


® Registered trademark of the International Electrotechnical Commission

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– 2 – IEC TS 62898-3-4:2023 © IEC 2023
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 10
3.1 Terms and definitions . 10
3.2  Abbreviated terms . 12
4 Overview . 12
4.1 General . 12
4.2 System architecture . 13
4.2.1 Stand-alone MMCS . 13
4.2.2 Integrated MMCS . 14
4.3 Hardware and software architectures . 14
4.3.1 Hardware . 14
4.3.2 Software . 15
4.3.3 Database . 15
4.4 Communication and cyber security . 15
4.4.1 Communication . 15
4.4.2 Cyber security . 16
5 Functional requirements . 17
5.1 Data acquisition and processing . 17
5.1.1 Data acquisition . 17
5.1.2 Data processing . 17
5.2 Database management . 18
5.3 Human-machine interface . 18
5.4 Anti-maloperation locking and alarm . 19
5.5 Time synchronization . 20
5.6 Local power quality control . 20
5.7 Frequency/voltage regulation during steady state operation of isolated
microgrid . 20
5.8 Sequence of operations . 21
5.9 Control of device switching . 21
5.10 Operating mode transition . 21
5.10.1 General . 21
5.10.2 Transition from island mode to grid-connected mode . 22
5.10.3 Transition from grid-connected mode to island mode . 22
5.11 Active and reactive power control . 22
5.11.1 General . 22
5.11.2 Active power control . 22
5.11.3 Reactive power control and voltage control . 23
5.12 Islanding detection . 23
5.13 Black start. 24
Annex A (informative) Example of collected information of MMCS . 25
A.1 Microgrid operating data . 25
A.1.1 Status data . 25
A.1.2 Measurement data . 25

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IEC TS 62898-3-4:2023 © IEC 2023 – 3 –
A.2 Microgrid equipment operating status data . 26
A.2.1 Primary equipment operating status data . 26
A.2.2 Secondary equipment operating status data . 26
A.2.3 Auxiliary equipment operating status data . 26
A.3 Microgrid forecast data . 27
A.4 Distributed energy planning data . 27
Annex B (informative) Examples of actual microgrid applications and the associated
functions of MMCS . 28
B.1 Application CN1: MMCS of microgrid with photovoltaic and battery

compacted with monitoring and control system of intelligent office park . 28
B.1.1 General . 28
B.1.2 System structure of MMCS . 29
B.1.3 Main functions of MMCS . 29
B.1.4 Applications . 30
B.2 Application CN2: MMCS of MV small hydropower microgrid for solving power

supply problems in remote areas . 30
B.2.1 General . 30
B.2.2 System structure of MMCS . 31
B.2.3 Main functions of MMCS . 32
B.2.4 Applications . 34
B.3 Application JP1: Power stabilization with combining high-speed ΔF and ΔP
suppression control utilizing storage batteries connected to thermal
generation: the IKI island demonstration project from Japan . 36
B.3.1 General . 36
B.3.2 Purpose . 37
B.3.3 Main functions of MMCS . 37
B.3.4 Applications . 38
Bibliography . 40


Figure 1 – Functional mapping for operation and control of microgrids . 13
Figure 2 – Structure of MMCS . 14
Figure 3 – Typical three-layer communication for structure 1 . 16
Figure 4 – Typical two-layer communication for structure 2 . 16
Figure B.1 – Primary structure of Chengchuang microgrid. 28
Figure B.2 – System structure of MMCS . 29
Figure B.3 – The main single line diagram of the small hydropower microgrid . 31
Figure B.4 – The main structure of MMCS. 32
Figure B.5 – Daily voltage curve along the common line and Fengshan line before the
implementation of microgrid in flooding period and heavy load . 34
Figure B.6 – Daily voltage curve along the common line and Fengshan line after the
implementation of microgrid . 35
Figure B.7 – Daily voltage curve along the common line and Fengshan line before the
implementation of microgrid . 35
Figure B.8 – Daily voltage curve along the common line and Fengshan line after the
implementation of microgrid . 36
Figure B.9 – Overview of Iki Island power system and battery . 37
Figure B.10 – Overview of control flow . 38
Figure B.11 – Example of stable frequency due to storage battery charge / discharge . 39

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INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________

MICROGRIDS

Part 3-4: Technical requirements –
Microgrid monitoring and control systems

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
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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
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4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
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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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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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 TS 62898-3-4 has been prepared by subcommittee 8B: Decentralized electrical energy
systems, 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
8B/154/DTS 8B/178/RVDTS

Full information on the voting for its approval can be found in the report on voting indicated in
the above table.

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IEC TS 62898-3-4:2023 © IEC 2023 – 5 –
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.
A list of all parts in the IEC 62898 series, published under the general title Microgrids, 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,
• replaced by a revised edition, or
• amended.

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– 6 – IEC TS 62898-3-4:2023 © IEC 2023
INTRODUCTION
Microgrids can serve different purposes depending on the primary objectives of their
applications. They are usually seen as means to manage reliability of supply and local
optimization of energy supply by controlling distributed energy resources (DER). Microgrids
also present a way to provide electricity supply in remote areas and to use clean and renewable
energy as a systemic approach for rural electrification.
At present, there are many types of microgrid, often composed of distributed generation, battery
energy storage, load, and other equipment. To achieve the effective integration and cooperative
operation of the above equipment, a set of computer systems is often required, which is
normally named as microgrid monitoring and control system. With the popularization of
microgrids, the industry urgently needs a standard to specify the system architecture,
component composition and functional requirements of microgrid monitoring and control system.
There are also various types of microgrid monitoring and control systems. For large scale
(installed power > 100 kW) microgrid, its monitoring system and control system is more complex,
usually using independent servers, workstations, remote terminal units, and others. Its
communication protocol and data model can be based on the IEC 61850 series, and the system
consists of a master station level and a local equipment level. For small-scale microgrids below
100 kW level, such as household microgrids with photovoltaic power generation and battery
storage, it is relatively expensive to configure a complex microgrid monitoring and control
system. At this time, the microgrid will generally adopt lightweight and cheap technical solutions,
and the microgrid monitoring, control and energy management function will often be combined
into a single device. Sometimes, for the small microgrid in remote mountainous areas, microgrid
monitoring and control system based on the Internet of Things and cloud computing architecture
is often used to realize the local autonomy and remote monitoring of the micro grid.
IEC TS 62898 series is intended to provide general guidelines and technical requirements for
microgrid projects.
IEC TS 62898-1 mainly covers the following issues:
• determination of microgrid purposes and application,
• preliminary study necessary for microgrid planning, including resource analysis, load
forecast, DER planning and power system planning,
• principles of microgrid technical requirements that should be specified during planning
stage,
• microgrid evaluation to select an optimal microgrid planning scheme.
IEC TS 62898-2 mainly covers the following issues:
• operation requirements and control targets of microgrids under various operation modes,
• the basic control strategies and methods under various operation modes,
• the requirements of electrical energy storage (EES), relay protection, monitoring and
communication under various operation modes,
• power quality.
IEC TS 62898-3-XX subseries technical specifications deal with the technical requirements of
microgrids.
IEC TS 62898-3-1 mainly covers the following issues:
• requirements for microgrid protection,
• protection systems for microgrids,
• dynamic control for transient and dynamic disturbances in microgrids.

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IEC TS 62898-3-4:2023 © IEC 2023 – 7 –
1
IEC TS 62898-3-2 covers the energy management system of microgrids.
IEC TS 62898-3-3 covers the self-regulation of dispatchable loads of microgrids.
This document covers microgrid monitoring and control systems (MMCS). It aims to provide
requirements to address state monitoring and operation control problems in microgrids.


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1
Under preparation.

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MICROGRIDS

Part 3-4: Technical requirements –
Microgrid monitoring and control systems



1 Scope
The purpose of this part of IEC 62898 is to provide technical requirements for the monitoring
and control of microgrids. This document applies to non-isolated or isolated microgrids
integrated with distributed energy resources. This document describes the specific
recommendations for low-voltage (LV) and medium-voltage (MV) microgrids.
This document focuses on standardization of the architecture, functions, and operation of
microgrid monitoring and control systems (MMCS). It teases out the general functions of MMCS
and provides technical requirements for MMCS. This document includes the following aspects
of MMCS:
• system architecture,
• information exchange with other devices/functions in microgrid,
• performance requirement,
• main function descriptions.
The system architecture for MMCS:
• For a large scale (installed power > 100 kW) microgrid, microgrid energy management
system (MEMS) and MMCS are normally separated. MMCS normally contains data servers,
application servers, workstations, routers, information safety devices, SCADA,
communication system, distributed generation controller, microgrid central controller, load
controller, grid connection interface device and other ancillary equipment.
• For a small user-side microgrid (normally less than 100 kW), MEMS and MMCS are normally
merged into one embedded device with system on chip, which is named as microgrid
controller.
Main functions of MMCS:
• Data acquisition and processing, including collecting real-time data from the distributed
generation, load, switches, transformers and reactive power compensation devices, and
calculation and analysis of the acquired data.
• Database management, including maintaining, synchronizing, backing up, restoring the
acquired data, and providing the data interface with other internal and external applications.
• Human-machine interface, including the real-time monitor screen and interface which is
capable of remote control, mode switching, manual data entry, etc.
• Anti-maloperation locking and alarm, to lock the maloperation based on the predefined rule
and logic.
• Time synchronization, including receiving the time synchronization signal from Global
Navigation Satellite System (GNSS) or network time protocol (NTP) and synchronizing the
time of each device within the microgrid.
• Local power quality evaluation and control the ability to collect information of out-of-limit
voltage, power factor, harmonic, etc. and carry out control to improve power quality
accordingly.
• Frequency/voltage regulation during steady state operation of an isolated microgrid to
provide voltage and frequency inside an accepted operation range.

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IEC TS 62898-3-4:2023 © IEC 2023 – 9 –
• Sequence of operations, or steady transition from power-off to start-up and from start-up to
power-off.
• Switch control of devices within microgrids, including turning on and off loads, generation
units, transformers, reactive power compensation devices, etc.
• Islanding detection, including real-time detection on power outage of the upstream
distribution system.
• Operation mode transition, including transition from grid-connected mode to island mode
and transition from island mode to grid-connected mode.
• Active and reactive power control, including load shedding (if required), load sharing and
controlling the active and reactive power in real time according to the MEMS or manual
command.
• Black start, the ability to initiate power sources and loads to ensure the microgrid can initiate
operation from a non-energized state.
• Interface with the protection system or earthing system when adaptations are required
according to the microgrid operating modes.
2 Normative references
The following documents are referred to in the text in such a way that some or all 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 60870-5-101, Telecontrol equipment and systems – Part 5-101: Transmission protocols –
Companion standard for basic telecontrol tasks
IEC 60870-5-104, Telecontrol equipment and systems – Part 5-104: Transmission protocols –
Network access for IEC 60870-5-101 using standard transport profiles
IEC 61850 (all parts), Communication networks and systems for power utility automation
IEC 62443 (all parts), Security for industrial automation and control systems
IEC 62586-1, Power quality measurement in power supply systems – Part 1: Power quality
instruments (PQI)
IEC TS 62898-1, Microgrids – Part 1: Guidelines for microgrid projects planning and
specification
IEC TS 62898-2, Microgrids – Part 2: Guidelines for operation
IEC TS 62898-3-1, Microgrids – Part 3-1: Technical requirements – Protection and dynamic
control
2
IEC TS 62898-3-2:— , Microgrids – Part 3-2: Technical requirements – Energy management
systems
IEC TS 62898-3-3, Microgrids − Part 3-3: Technical requirements − Self-regulation of
dispatchable loads
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2
Under preparation. Stage at the time of preparation: IEC DTS 62898-3-2:2023.

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IEEE Std 1815-2012, IEEE Standard for Electric Power Systems Communications-Distributed
Network Protocol (DNP3)
IRIG-B Standards Documentation (IRIG.ORG) [viewed 2023-08-07]
Modbus Standards Documentation (Modbus.org) [viewed 2023-08-07]
NTP Standards Documentation (ntp.org) [viewed 2023-08-07]
OASIS Standards Documentation, MQTT Version 5.0 (oasis-open.org) [viewed 2023-07-24]
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
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
3.1.1
microgrid
group of interconnected loads and distributed energy resources with
defined electrical boundaries forming a local electric power system at distribution voltage levels,
that acts as a single controllable entity and is able to operate in island mode, no matter if it is
st
...