Communication networks and systems for power utility automation - Part 7-5: IEC 61850 modelling concepts

IEC TR 61850-7-5:2021, which is a technical report, establishes modelling concepts that help the user to understand how to apply the models defined in IEC 61850-7-4 and IEC 61850-7-3 to implement practical applications.
This document provides the basic concepts that are valid for all application domains using IEC 61850. Domain specific concepts are defined in other technical reports as in the document range of IEC 61850-7-5xx; as an example, IEC 61850-7-500 describes modelling concepts for functions related to substation automation.
On one side the number of potential topics for cross-domain modelling may be very high but on the other side it may be limited by domain specific restrictions often created by the historical evolution of IEC 61850 in the domains.
The first topic selected is the common control of power utility primary objects by means of the power utility automation systems based mainly on the long experience in substation automation systems. Common attributes for reliable power utility automation systems in all domains are quality and health. A special function having a broad application range in power utility automation systems is the scheduling of services as provided by the domain distributed energy resources (DER) used in smart grids, especially also for electric mobility. Not yet so much discussed in the context of IEC 61850 but very important for all IEDs is the impact of restart (power cycle) on the data model parameters. Non-agreed behaviour will raise problems for interoperability in multi-vendor systems.

General Information

Status
Published
Publication Date
25-Apr-2021
Current Stage
PPUB - Publication issued
Completion Date
26-Apr-2021
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IEC TR 61850-7-5
Edition 1.0 2021-04
TECHNICAL
REPORT
colour
inside
Communication networks and systems for power utility automation –
Part 7-5: IEC 61850 Modelling concepts
IEC TR 61850-7-5: 2021-04 (en)
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---------------------- Page: 2 ----------------------
IEC TR 61850-7-5
Edition 1.0 2021-04
TECHNICAL
REPORT
colour
inside
Communication networks and systems for power utility automation –
Part 7-5: IEC 61850 Modelling concepts
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.200 ISBN 978-2-8322-9647-9

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

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TR 61850-7-5:2021  IEC 2021
CONTENTS

CONTENTS ............................................................................................................................ 2

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

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

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

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

3 Terms, definitions and abbreviated terms ........................................................................ 8

3.1 Terms and definitions.............................................................................................. 8

3.2 Abbreviated terms ................................................................................................... 8

4 Control ............................................................................................................................ 8

4.1 Control authorization ............................................................................................... 8

4.1.1 Basics ............................................................................................................. 8

4.1.2 Validating a control request ............................................................................. 9

4.1.3 Exclusive control authorization for one out of multiple actors of the

same level of control hierarchy ...................................................................... 12

4.1.4 Different control permissions for different actors of the same level of

control hierarchy ............................................................................................ 13

4.2 Control authority for process equipment ................................................................ 13

4.2.1 Control commands for process equipment from automations instead of

HMI ............................................................................................................... 13

5 Quality and its propagation ............................................................................................ 15

5.1 Standard processing principle ............................................................................... 15

5.1.1 General ......................................................................................................... 15

5.1.2 Respecting behaviour .................................................................................... 15

5.1.3 LN specific calculations ................................................................................. 16

5.1.4 detailQual is not propagated .......................................................................... 16

5.1.5 Configurable propagation of the value of the element ‘source’ ....................... 16

5.1.6 operatorBlocked is not propagated ................................................................ 16

5.2 Special processing principle for (single phase) XCBR mapping to CSWI ............... 16

5.2.1 General ......................................................................................................... 16

5.2.2 Respecting the Behaviour .............................................................................. 18

5.2.3 LN specific calculations ................................................................................. 18

5.2.4 Propagation of detailQual .............................................................................. 18

5.2.5 Substitution of switchgear position signals ..................................................... 18

5.2.6 operatorBlocked is not propagated ................................................................ 19

5.3 Conclusion ............................................................................................................ 19

6 Health and its application .............................................................................................. 20

6.1 General ................................................................................................................. 20

6.2 The use of LPHD.PhyHealth, LLN0.Health, LN.Health and LN.EEHealth ............... 20

6.3 Health in Proxy-IEDs, in LNs of type Mirror and in a LD hierarchy ......................... 22

7 Special functions ........................................................................................................... 24

7.1 Use of cross domain schedules and scheduler ...................................................... 24

7.1.1 Introduction ................................................................................................... 24

7.1.2 Example 1 ..................................................................................................... 25

7.1.3 Example 2 ..................................................................................................... 28

8 Restoration of functions/communication after IED restart (power cycle) ......................... 31

8.1 Functional description ........................................................................................... 31

---------------------- Page: 4 ----------------------
IEC TR 61850-7-5:2021  IEC 2021 – 3 –

8.2 Priorities ............................................................................................................... 31

8.3 Stored and non-stored data................................................................................... 31

Bibliography .......................................................................................................................... 33

Figure 1 – Communication vs. application layer model for controls ......................................... 9

Figure 2 – Different levels of control authority (example) ...................................................... 12

Figure 3 – Single-phase monitoring of the CB position .......................................................... 17

Figure 4 – Examples of use of Health and EEHealth in models ............................................. 23

Figure 5 – FSCH and FSCC LN class ................................................................................... 24

Figure 6 – State Machine ...................................................................................................... 25

Figure 7 – Relation between schedule controller, schedules and entity scheduled ................ 25

Figure 8 – Use case charging architecture ............................................................................ 26

Figure 9 – LN instances and relationships in example 1 ........................................................ 27

Figure 10 – Timelines associated to the example 1 ............................................................... 27

Figure 11 – LN instances and relationships in example 2 ...................................................... 28

Figure 12 – Timelines associated to the example 2 ............................................................... 30

Table 1 – Dependence of checking Interlocking (IL) conditions on the control command

and on the server configuration ............................................................................................. 10

Table 2 – Dependence of checking synchronism (CS) conditions on the control

command and on the server configuration ............................................................................. 11

Table 3 – Use case 1 definition ............................................................................................. 14

Table 4 – Example of fixed rules: Boolean OR out of two input signals ................................. 19

Table 5 – Health in IEC 61850-7-4 ........................................................................................ 21

Table 6 – Examples for stored and non-stored data for restart .............................................. 32

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– 4 – IEC TR 61850-7-5:2021  IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
COMMUNICATION NETWORKS AND SYSTEMS
FOR POWER UTILITY AUTOMATION –
Part 7-5: IEC 61850 Modelling concepts
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

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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 TR 61850-7-5 has been prepared by Working Group 10 of IEC Technical Committee 57:

Power systems management and associated information exchange. It is a Technical Report.

The text of this Technical Report is based on the following documents:
DTR Report on voting
57/2253/DTR 57/2322/RVDTR

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 Report 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

---------------------- Page: 6 ----------------------
IEC TR 61850-7-5:2021  IEC 2021 – 5 –

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.

A list of all parts in the IEC 61850 series, published under the general title Communication

networks and systems for power utility automation, 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

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of its contents. Users should therefore print this document using a colour printer.

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– 6 – IEC TR 61850-7-5:2021  IEC 2021
INTRODUCTION

The IEC 61850 standard series provides a very broad range of data models covering as much

as possible all application functions in the range of power utility automation. The modelling both

in the domains and between the domains show differences which may impact interoperability.

Therefore, some informative guidelines are helpful to reach a common approach in application

function modelling. A lot of basic functionality is based on the concept of IEC 61850 and is,

therefore, the same for all application domains. As result, a basic cross-domain part in the form

of a Technical Report is useful. Domain specific issues are addressed in the Technical Reports

IEC TR 61850-7-5xx (e.g. IEC TR 61850-7-500 for substation automation).

To cover all domains in a comprehensive way would not come to a result in a reasonable time.

This may be a task for future editions of this document. Therefore, this document describes in

selected examples the use of logical nodes for modelling application functions and related

concepts and guidelines in general independently from any application domain respectively

valid for all application domains in the utility automation (substation automation, distributed

energy resources, hydro power, wind power, etc.). It also includes some tutorial material where

helpful.

The modelling of the use cases given in this document is based on the class model introduced

in IEC 61850-7-1. The logical node and data names used in this document are defined in

IEC 61850-7-4 and IEC 61850-7-3, the services applied in IEC 61850-7-2. If needed for the

understanding of modelling these use cases, the application of services is also described. If

different options cannot be excluded, all options may be mentioned.

If extensions are needed in the use cases, the normative naming rules for multiple instances

and private, compatible extensions of Logical Node (LN) Classes and Data Object (DO) Names

defined in IEC 61850-7-1 are considered.
---------------------- Page: 8 ----------------------
IEC TR 61850-7-5:2021  IEC 2021 – 7 –
COMMUNICATION NETWORKS AND SYSTEMS
FOR POWER UTILITY AUTOMATION –
Part 7-5: IEC 61850 Modelling concepts
1 Scope

This part of IEC 61850, which is a technical report, establishes modelling concepts that help

the user to understand how to apply the models defined in IEC 61850-7-4 and IEC 61850-7-3

to implement practical applications.

This document provides the basic concepts that are valid for all application domains using

IEC 61850. Domain specific concepts are defined in other technical reports as in the document

range of IEC 61850-7-5xx; as an example, IEC 61850-7-500 describes modelling concepts for

functions related to substation automation.

On one side the number of potential topics for cross-domain modelling may be very high but on

the other side it may be limited by domain specific restrictions often created by the historical

evolution of IEC 61850 in the domains.

The first topic selected is the common control of power utility primary objects by means of the

power utility automation systems based mainly on the long experience in substation automation

systems. Common attributes for reliable power utility automation systems in all domains are

quality and health. A special function having a broad application range in power utility

automation systems is the scheduling of services as provided by the domain distributed energy

resources (DER) used in smart grids, especially also for electric mobility. Not yet so much

discussed in the context of IEC 61850 but very important for all IEDs is the impact of restart

(power cycle) on the data model parameters. Non-agreed behaviour will raise problems for

interoperability in multi-vendor systems.
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 61850-2, Communication networks and systems for power utility automation - Part 2:

Glossary

IEC 61850-7-1, Communication networks and systems for power utility automation - Part 7-1:

Basic communication structure - Principles and models

IEC 61850-7-2:2010, Communication networks and systems for power utility automation - Part

7-2: Basic information and communication structure - Abstract communication service interface

(ACSI)
IEC 61850-7-2:2010/AMD1:2020

IEC 61850-7-4:2010, Communication networks and systems for power utility automation - Part

7-4: Basic communication structure - Compatible logical node classes and data object classes

IEC 61850-7-4:2010/AMD1:2020
---------------------- Page: 9 ----------------------
– 8 – IEC TR 61850-7-5:2021  IEC 2021

IEC TR 61850-7-500, Communication networks and systems for power utility automation - Part

7-500: Basic information and communication structure - Use of logical nodes for modeling

application functions and related concepts and guidelines for substations

IEC 61850-8-1, Communication networks and systems for power utility automation - Part 8-1:

Specific communication service mapping (SCSM) - Mappings to MMS (ISO 9506-1 and ISO

9506-2) and to ISO/IEC 8802-3

IEC 61850-8-2, Communication networks and systems for power utility automation - Part 8-2:

Specific communication service mapping (SCSM) - Mapping to Extensible Messaging Presence

Protocol (XMPP)

IEC TR 61850-90-2, Communication networks and systems for power utility automation - Part

90-2: Using IEC 61850 for communication between substations and control centres

IEC TR 61850-90-8, Communication networks and systems for power utility automation - Part

90-8: Object model for E-mobility

IEC 62351, Power systems management and associated information exchange – Data and

communications security (all parts)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document the terms and definitions given in IEC 61850-2 and

IEC 61850-7-2 apply.

ISO and IEC maintain terminological 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/ui
3.2 Abbreviated terms
EV Electric vehicle
IL Checking Interlocking
NCC Network Control Centre
CS Checking Synchronism
4 Control
4.1 Control authorization
4.1.1 Basics

Control (control commands) crosses various layers and may require authentication and

authorization before it arrives at the controllable object. Figure 1 shows the various layers.

---------------------- Page: 10 ----------------------
IEC TR 61850-7-5:2021  IEC 2021 – 9 –
Figure 1 – Communication vs. application layer model for controls
• Mapping to protocol

To pass a control command from a client (which issues the control) to a server (which

executes the control command) both located in two different IEDs, the command needs to

be mapped to a protocol. For exchanges within substations and for tunnelling through

external communication systems to other substations and to the NCC a mapping to

Manufacturing Message Specification (MMS) above Ethernet according to IEC 61850-8-1 is

preferred. In addition, also mapping to GOOSE according to IEC 61850-8-1 may be used.

For the usage outside substations beside the message tunnelling and message conversion

for non-IEC 61850 communication networks especially at distribution level a mapping to web

technology protocol as described in IEC 61850-8-2 may be more appropriate.
• Control services

The flexibility of being able to choose a protocol to map to is granted thanks to the fact that

controls are defined in IEC 61850-7-2 as control services of an Abstract Communication

Service Interface (ACSI). These control services are tailored to the applications of the power

utility automation domain.
• Management of multiple control points

Where a control is an exclusive exchange of requests and responses between two peers,

network automation systems need to also allow for applications where more than one control

point may issue controls to a controllable object. The management of parallel accesses is

performed on the basis of user specific rules depending on operational philosophy.

• Authentication and authorization

The means and methods provided by the IEC 62351 series on communication network and

system security will ensure that only authenticated clients may have defined access to given

parts of a power utility automation system. It is furthermore up to the roles and to the

permissions granted to this client whether its control request to a given controllable object

is accepted.
4.1.2 Validating a control request
4.1.2.1 General

Before a control is executed, the command shall pass several steps in approval, reflecting

different aspects of validation.
---------------------- Page: 11 ----------------------
– 10 – IEC TR 61850-7-5:2021  IEC 2021
4.1.2.2 Validation against the LN behaviour

The control request is forwarded to the function in charge of the controllable data object

addressed in the control service. When reaching a function for control, the LN behaviour (e.g.

represented by the actual value of the DO CSWI.Beh) shall decide whether the control can be

processed or not, following IEC 61850-7-2. Since functions are accessible via communication

in all the five states of their functional behaviour DO LN.Beh, a response has always given.

4.1.2.3 Validation against the control model

Depending on the control model which is set for the controllable object, the IED shall perform

various checks against the command. The explicit order is out of the scope of the standard

IEC 61850. Since the use of SBO control with enhanced security according to IEC 61850-7-2

is the common model for switchgear control, the current clause delves neither into direct

operate, nor into SBO with normal security.
4.1.2.4 Test whether the conditions are met
4.1.2.4.1 General

Two kinds of tests may be performed: ‘operative test’ depending on the operative condition of

the object and its process environment, and ‘dynamic test’, e.g. checking the moment of

allowance for the command to the object. In its control request the client shall specify whether

synchrocheck and interlocking check are to be performed. If the addressed function respectively

the data object does not support these checks (not implemented, not configured), the

appropriate check bits of the control request are ignored and the command is performed

directly, see IEC 61850-7-2:2010, Table 110.
4.1.2.4.2 Operative test

The control hierarchy function has to be configured according to the operations requirement of

the user. The control authority shall be checked by comparing the state (XXXX.Loc) of control

hierarchy active in the function hosting the controllable object against the order category

submitted in the actual command. Plausibility checking shall run to see whether the intended

operation does not contradict to the actual position of the switchgear. To validate the switchgear

control against the conditions of interlocking (IL) with the positions of other switchgear, the

release output of the interlocking function CILO is taken as criteria for approval (see Table 1).

The control of the switchgear shall be validated against the readiness of the equipment for an

operation (consideration of EEHealth, BlkCls, supervisions through SCBR, etc.).
Table 1 – Dependence of checking Interlocking (IL) conditions
on the control command and on the server configuration
LN, DO configuration → No IL check IL check No IL check IL check
↓ Control context
SwModKey = F SwModKey = T
no CheckCondition N N N N
from client
(NCC, station
IL CheckCondition
N Y N N
HMI)
set
from IED level not specified N Y N N

Then, upon SelectWithValue, the object is reserved for this actor, unless associated checks

(1-out-of-n, client reservation e.g.) would lead to a rejection of the control, documented with the

appropriate AddCauses. All other objects are deselected.
---------------------- Page: 12 ----------------------
IEC TR 61850-7-5:2021  IEC 2021 – 11 –
4.1.2.4.3 Dynamic test

In a second step, upon receipt of the Operate, the synchrocheck release (RSYN.Rel) shall be

checked (see Table 2). The synchrocheck is only applicable for circuit breakers which may

connect separated parts of the power grid.
Table 2 – Dependence of checking synchronism (CS) conditions
on the control command and on the server configuration
LN, DO configuration → No CS check CS check
↓ Control context
no CheckCondition N N
from client
(NCC, station
CS CheckCondition
N Y
HMI)
set
from IED level not specified N Y

As soon as the control passed the approval for execution on the switch controller level, the

function which is modelling the controllable data object (here: XCBR.Pos, XSWI.Pos) is

triggered. Depending on the device layout and on the functional distribution, similar checks

...

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