IEC 61970-407:2007

IEC 61970-407
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
Energy management system application program interface (EMS-API) –
Part 407: Time Series Data Access (TSDA)

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
3, rue de Varembé
CH-1211 Geneva 20
Switzerland
Email: inmail@iec.ch
Web: www.iec.ch
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 corrigenda or an amendment might have been published.
ƒ Catalogue of IEC publications: www.iec.ch/searchpub
The IEC on-line Catalogue enables you to search by a variety of criteria (reference number, text, technical committee,…).
It also gives information on projects, withdrawn and replaced publications.
ƒ IEC Just Published: www.iec.ch/online_news/justpub
Stay up to date on all new IEC publications. Just Published details twice a month all new publications released. Available
on-line and also by email.
ƒ Electropedia: www.electropedia.org
The world's leading online dictionary of electronic and electrical terms containing more than 20 000 terms and definitions
in English and French, with equivalent terms in additional languages. Also known as the International Electrotechnical
Vocabulary online.
ƒ Customer Service Centre: www.iec.ch/webstore/custserv
If you wish to give us your feedback on this publication or need further assistance, please visit the Customer Service
Centre FAQ or contact us:
Email: csc@iec.ch
Tel.: +41 22 919 02 11
Fax: +41 22 919 03 00
IEC 61970-407
Edition 1.0 2007-08
INTERNATIONAL
STANDARD
Energy management system application program interface (EMS-API) –
Part 407: Time Series Data Access (TSDA)

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
S
ICS 33.200 ISBN 2-8318-9253-8
– 2 – 61970-407 © IEC:2007(E)
CONTENTS
FOREWORD.3

INTRODUCTION.5

1 Scope.6

2 Normative references .7

3 Terms, definitions and identification conventions .7

3.1 Terms and definitions .7

3.2 Conventions .7
4 CIS Specification.7
4.1 Background (informative) .7
4.2 Historian use case (informative) .8
4.3 Data model.10
4.4 Messages (normative) .13
4.5 Interface (normative) .13
4.5.1 Objects and interfaces.13
4.5.2 Server and Session interfaces .16
4.5.3 Management interfaces .17
4.5.4 Browse interfaces.17
4.5.5 IO interfaces.18
4.5.6 Client interfaces .20
4.6 Mapping of TSDA .20

Figure 1 – Control system structure .9
Figure 2 – TSDA server and clients.10
Figure 3 – Data subscription .10
Figure 4 – TSDA data model.11
Figure 5 – TSDA objects and interfaces .14
Figure 6 – Typical Interaction between the TSDA objects.16

61970-407 © IEC:2007(E) – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION

___________
ENERGY MANAGEMENT SYSTEM
APPLICATION PROGRAM INTERFACE (EMS-API) –

Part 407: Time Series Data Access (TSDA)

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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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.
International Standard IEC 61970-407 has been prepared by IEC Technical Committee 57:
Power systems management and associated information exchange.
The text of this standard is based on the following documents:
FDIS Report on voting
57/889/FDIS 57/908/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
A list of all parts of the IEC 61970 series, under the general title Energy Management System
Application Program Interface (EMS-API), can be found on the IEC website.

– 4 – 61970-407 © IEC:2007(E)
The committee has decided that the contents of this publication will remain unchanged until

the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in

the data related to the specific publication. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or

• amended.
A bilingual version of this publication may be issued at a later date.

61970-407 © IEC:2007(E) – 5 –
INTRODUCTION
This part of IEC 61970 is part of the IEC 61970 series that defines Application Program

Interfaces (APIs) for an Energy Management System (EMS). The IEC 61970-4XX and

IEC 61970-5XX series documents comprise Component Interface Specifications (CISs). The

IEC 61970-4XX series CIS are specified as Platform Independent Models (PIMs), which

means they are independent of the underlying technology used to implement them. PIM

specifications are also referred to as Level 1 specifications. The IEC 61970-5XX series CIS,

on the other hand, are specified as Platform Specific Models (PSMs). PSM specifications are

also referred to as Level 2 specifications.

IEC 61970-4XX CISs specify the functional requirements for interfaces that a component (or
application) should implement to exchange information with other components (or
applications) and/or to access publicly available data in a standard way. The component
interfaces describe the specific event types and message contents that can be used by
applications for this purpose.
IEC 61970-407 specifies an interface for the efficient transfer of time series data in a
distributed environment. Small amounts of data are transferred with short delay but also large
amounts of data are transferred in short time but with possibly longer delay. Replay of time
series data is also supported. This is a typical requirement for a SCADA system that acts as a
real time data provider to other sub-systems. Other systems than SCADA may also benefit
from the characteristics of TSDA. When short delay times as well as bulk data transfer is
required TSDA is a good fit.
These component interface specifications refer to entity objects for the power system domain
that is defined in the IEC 61970-3XX series, including IEC 61970-301.

– 6 – 61970-407 © IEC:2007(E)
ENERGY MANAGEMENT SYSTEM
APPLICATION PROGRAM INTERFACE (EMS-API) –

Part 407: Time Series Data Access (TSDA)

1 Scope
The IEC 61970-407 Time Series Data Access (TSDA) specification specifies a generalized
interface for efficient exchange of data. The specification takes into account the latencies
caused by a Local Area Network (LAN) providing efficient data exchange also over Local Area
Networks.
IEC 61970-407 is derived from the Object Management Group (OMG) Historical Data Access
from Industrial Systems (HDAIS) specification. OMG HDAIS relies on the OMG Data Access
Facility (DAF) and OPC Historical Data Access (HDA) specifications. OMG HDAIS is a
Platform Specific Model (PSM) with CORBA as the platform and OPC HDA is a PSM with
Microsoft COM as the platform. The IEC 61970-407 specification describes the functionality of
these PSMs in a technology independent way (i.e., as a Platform Independent Model (PIM)).
Hence, it explains the functionality to a level that can be used to create additional PSMs or be
an introduction to existing PSMs, i.e. HDAIS and OPC HDA. Implementers wanting an
introduction to OMG HDAIS and OPC HDA should read these documents.
The TSDA interface is intended to interoperate with other IEC 61970 based interfaces. Hence,
it is possible to use information retrieved from other interface to access the same information
using this interface, for example:
• object identifiers,
• attribute names or identifiers,
• class names or identifiers.
Subclause 4.6 provides a generic mapping for the CIM classes and attributes.
The way data is organized in a server implementing the TSDA interface can be seen by using
the browse interfaces for data and meta data. It is also possible to use the data access
interface directly without using the browse interfaces if the client has an a priori knowledge of
object, class and attribute identifiers. Object identifiers may be retrieved using data from other
interfaces, for example a CIMXML file or the IEC 61970-404 interface. Information on what
classes and attributes are available will be described in IEC 61970-45X documents, for

example historical SCADA data, historical State Estimator results etc.
IEC 61970-1 provides the EMS-API reference model upon which this standard is based. In
that reference model, the terminology used in this part of IEC 61970 is introduced and the role
of the CIS is explained.
IEC 61970-401 provides an overview and framework for the CIS (IEC 61970-4XX) standards.
The mapping of IEC 61970-407 to implementation specific technologies or PSMs is further
described in a separate series of documents, i.e. the future IEC 61970-5XX. For actual
implementations the future IEC 61970-5XX, OMG HDAIS, OMG DAF or OPC HDA are used.

61970-407 © IEC:2007(E) – 7 –
2 Normative references
The following referenced documents are indispensable for the application 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 61970-1, Energy management system application program interface (EMS-API) – Part 1:

Guidelines and general requirements

IEC/TS 61970-2, Energy management system application program interface (EMS-API) –

Part 2: Glossary
IEC 61970-301:2005, Energy management system application program interface (EMS-API) –
Part 301: Common Information Model (CIM) base
IEC 61970-401, Energy management system application program interface (EMS-API) –
Part 401: Component Interface Specification (CIS) Framework
IEC 61970-402, Energy management system application program interface (EMS-API) –
Part 402: Component Interface Specification (CIS) - Common Services
Historical Data Access from Industrial Systems (HDAIS), OMG Adopted Specification Version
1.0, dtc/2003-02-01 November 2003 (Referred herein as 'OMG HDAIS')
Utility Management System (UMS) Data Access Facility (DAF), OMG Adopted Specification,
Version 2.0, formal/02-11-08, November 2002 (Referred to herein as ‘OMG DAF’)
Data Acquisition from Industrial Systems (DAIS), OMG Adopted Specification Version 1.0,
formal/2002-11-07 November 2002 (Referred herein as 'OMG DAIS')
OPC Historical Data Access Custom Interface Specification, Version 1.20, OPC Foundation,
December 2003 (Referred to herein as ‘OPC HDA’)
3 Terms, definitions and identification conventions
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 61970-2 apply.
3.2 Conventions
A convention used in this document to uniquely identify a UML attribute is to concatenate the
class name and the attribute name with a period in between, for example, the attribute “id” in
the class “Node” will then be named “Node.id”. For attributes in sub structures multiple
attribute names may be used, for example “Item.id.node_id” where the “node_id” is a part in
the structure “Item.id”.
4 CIS Specification
4.1 Background (informative)
For historical reasons, control systems for different industrial processes have evolved along
different lines. Control systems for power systems have evolved on a UNIX base and control
systems for most other industrial processes have evolved on a Windows base. For Windows
based control systems, OPC has become the dominating standard. For UNIX based systems,
the DAIS/HDAIS API defined in Common Object Request Broker Architecture (CORBA)

– 8 – 61970-407 © IEC:2007(E)
Interface Definition Language (IDL) has been developed. DAIS/HDAIS is based on OPC to

benefit from the success of OPC and enable easy bridging to OPC. With this intent Object

Management Group (OMG) started in 1997 to develop a CORBA based interface with the

same functionality as OPC. TSDA has the functionality from OMG HDAIS and OPC HDA

described in a technology neutral way, hence TSDA is intended to be a Platform Independent

Model (PIM).
4.2 Historian use case (informative)

An important component in a utility operational system is a Historian or Utility Data

Warehouse (UDW) that acts as a repository for past or future time series data. A UDW acts as

a server to client components. Such a system typically has the following components:

• Process instrumentation making sensor data and actuation capabilities available.
• Remote Terminal Units (RTUs) or substation control systems reading sensor data and
controlling actuators.
• Process communication units connecting to RTUs or substation control systems. Remote
communication is typically solved by specialized RTU or field bus protocols (e.g.
IEC 60870-5). The IEC 61850 is a new standard for communication with and within
substations. The interfaces defined in this specification can be used as a standard API to
encapsulate such communication solutions at the client side.
• SCADA subsystem making processed sensor data and control capabilities available to
operators, applications or other systems.
• A Model based management system, for example Energy Management System (EMS),
using the SCADA subsystem for extended processing and control.
• A Graphical User Interface (GUI).
• UDW that stores time series data.
The architecture is shown in Figure 1 below.

61970-407 © IEC:2007(E) – 9 –
Data
traffic
across
TSDA clients
TSDA
API
Graphical User
Interface
Model based management
system (e.g. EMS)
Data
traffic
SCADA or
Historian or Data Warehouse
across
Telemetry system
(TSDA server)
HSDA
API
Process
Communication
Units
Process control
substation control
or RTU
Instrumentation
IEC  1334/07
Figure 1 – Control system structure
A UDW and possible clients using it are shown in Figure 2:
• Data sources recording data as the SCADA recording real time data, EMS recording
calculation results or GUI recording manually entered data.
• A Process Communication Unit providing time series data from remote sources.
• Clients, for example a GUI, retrieving data for discovery, presentation and

updates/corrections.
• Clients, for example analysis programs, retrieving data for analysis and or input to
calculations
• A UDW typically also has calculations that create new results from already stored time
series data.
– 10 – 61970-407 © IEC:2007(E)

Archive
Calculation
Utility Data Server
of new data
Warehouse
Communication supported by API

Data source
Discovery Presentation Update Analysis
(recording)
Clients
IEC  1335/07
Figure 2 – TSDA server and clients
TSDA supports both subscription and read/write operations. The concept of subscription is
described in Figure 3.
Client
Establish
Callbacks for
subscription
data transfer
Server or
Data provider
IEC  1336/07
Figure 3 – Data subscription
A subscription involves a server that publishes data and clients that subscribe to receive the
data. The server has no a priori knowledge of its clients; they become known to the server

when a client creates a subscription. Once a subscription is established, the server calls the
client back when data becomes available or is updated.
4.3 Data model
The TSDA data model describes how data seen through the TSDA interface appears to be
organized within a server. A server implementation may organize data differently, but a client
using TSDA will see a data model as shown in Figure 4.

61970-407 © IEC:2007(E) – 11 –

0.0.**
ItemID
Node
node_id : ID
id : ID
Item
property_id : ID
00.1.1 label : String
id : ItemID
pathname : Strin.
pathname : Strin.
00.*.*
type_id : ID 11
parent_id : ID
00.*.*
00.*.*
0.0.**
0.0.** +time_series
ItemAttribute
ItemValue
item_id : ItemID
value : Simple
definition : ID 11
quality : Quality
time_stamp : DateTime
0.0.**
+time_series
0.0.**
ItemAttributeValue
11 ModifiedItemValue
value : Simple
modification_time : DateTime
time_stamp : DateTime
+modification
user_name : String
value : Simple
00.1.1
quality : Quality
ItemAttributeDefintion
id : ID
Annotation
label : String
entry_time : DateTime
+annotation
data_type : SimpleType
text : String
00.1.1 user_name : String
Property
AggregateDefinition
Type
id : ID
id : ID
id : ID label : String
label : String
label : String data_type : SimpleType
0.0.**
type_id : ID
0.0.**
+aggregated_types
IEC  1337/07
Figure 4 – TSDA data model
The following objects are defined in the model:

• Type, which describes objects with the same time series characteristics, for example the
time interval between values, calculations of values etc. Hence, the TSDA Type is different
from the HSDA Type. The HSDA Types typically describe the types defined in IEC 61970-
301 while the TSDA Type has no corresponding description in IEC 61970-301. However, a
TSDA Type usually refers to a HSDA Type.
• Property, which describes the Items recorded as time series. A TSDA Property usually
refers to a HSDA Property. A Type can have any number of Properties.
• ItemAttributeDefinition, which describes ItemAttributes specific to time series data.
ItemAttributeDefinitions are similar to the Properties in that it describe time series data but
different as the data is specific to the time series. Several ItemAttributeDefinitions usually
exist for a Type.
• ItemAttribute, which describes how Items are treated within a TSDA server, i.e. it is meta
data for Item time
...