SCADA Standards Organizations

7.0  SCADA Standards Organizations

There are many organizations involved in the standardization of SCADA systems.  This section details some of these organizations and the roles they play. 

7.1 The Institute of Electrical and Electronics Engineers (IEEE) 

The IEEE Standards Association (IEEE-SA) is a membership organization that produces Electrical and IT-Related standards that are used internationally. The IEEE has been involved in standardizing technologies for many years.  The following standards have been published by the IEEE with respect to SCADA systems:

•        IEEE Std 999-1992 – IEEE Recommended Practice for Master/Remote Supervisory Control and Data Acquisition (SCADA) Communications. This recommended practice applies to the use of serial digital transmissions by supervisory control and data acquisition (SCADA) systems having geographically dispersed terminals. These types of systems typically utilize dedicated communication channels, such as private microwave channels or leased telephone lines, which are limited to data rates of less then 10,000 b/s.

•        IEEE Std 1379-2000 – IEEE Recommended Practice for Data Communications Between Remote Terminal Units and Intelligent Electronic Devices in a Substation. This recommended practice presents a uniform set of guidelines for communications and interoperation of IEDs and RTUs in an electric utility substation. This recommended practice does not establish an underlying communication standard. Instead, it provides a specific limited subset of two existing communication protocols and encourages understanding and timely application.

7.2 American National Standards Institute 

The American National Standards Institute (ANSI) is a private, non-profit organization (501(c)3) that administers and coordinates the U.S. voluntary standardization and conformity assessment system.  The Institute's mission is to enhance both the global competitiveness of U.S. business and the U.S. quality of life by promoting and facilitating voluntary consensus standards and conformity assessment systems, and safeguarding their integrity. 

The mission of The American National Standards Institute's Homeland Security Standards Panel (ANSI-HSSP) is to identify existing consensus standards, or, if none exists, assist the Department of Homeland Security (DHS) and those sectors requesting assistance to accelerate development and adoption of consensus standards critical to homeland security. The ANSI-HSSP promotes a positive, cooperative partnership between the public and private sectors in order to meet the needs of the nation in this critical area. 

Established by ANSI in February 2003, the ANSI-HSSP’s  scope is to catalog, promote, accelerate and coordinate the timely development of consensus standards within the national and international voluntary standards systems intended to meet identified homeland security needs, and communicate the existence of such standards appropriately to governmental units and the private sector. The Panel will initially focus its activities on responding to the most immediate standards needs of DHS.

7.3 Electric Power Research Institute 

The Electric Power Research Institute (EPRI) was founded in 1973 as a non-profit energy research consortium for the benefit of utility members, their customers, and society. Their mission is to provide science and technology-based solutions of indispensable value to global energy customers by managing a far-reaching program of scientific research, technology development, and product implementation. 

EPRI is the only science and technology consortium serving the entire energy industryfrom energy conversion to end usein every region of the world. With expertise in a wide spectrum of scientific research, technology development, and product application, they are able to offer solutions that cut across traditional boundaries, taking advantage of the latest advances in many fields. EPRI provides the knowledge, tools, and expertise you need to build competitive advantage, address environmental challenges, open up new business opportunities, and meet the needs of your energy customers. 

The (EPRI) has developed The Utility Communications Architecture (UCA) to integrate communications for "real-time" utility operations for SCADA systems. The UCA is the only existing protocol that provides interoperability among different monitoring and control equipment and interconnectivity among databases for utility operations. The UCA Version 2 Specification has been recently published by the Institute of Electrical and Electronic Engineers (IEEE) Standards Board as Technical Report TR1550. EPRI takes great pride that the UCA technology has been published by the IEEE. In addition, UCA is in review by the International Electrotechnical Commission (IEC) to become the international standard for integrated utility operations. The new UCA Version 2 includes four parts that are published in two volumes, as follows:

·         TR1550 Volume 1: Part 1: Introduction to UCA (TM) Version 2.0; Part 2: UCA (TM) Profiles; Part 3: UCA (TM) Common Application Service Models (CASM). And TR1550 Volume 2: Part 4: UCA (TM) Generic Object Models for Substation and Feeder Equipment (GOMSFE) 

ü  Part 1: Introduction. Gives an overview of the UCA Version 2. This document presents a background, philosophy, and applications of UCA to provide a basic understanding of UCA. 

ü  Part 2: Profiles. Presents the profiles and protocols for various communication media, including local area networks, radio, fiber optic, and telephone; including guidelines on the use of the Internet protocols in a UCA context. 

ü  Part 3: Common Applications Services Model (CASM). Describes models for device behavior from a UCA communications perspective; it also defines the language, services, semantics, and applications of UCA. 

ü  Part 4: Generic Object Models for Field Equipment (GOMSFE). Presents a detailed list of device object models for a wide range of substation and distribution field equipment, including breakers, relays, sectionalizes, capacitor controllers, remote terminal units (RTUs), and other intelligent electronic devices (IEDs).

7.4 International Electrotechnical Commission 

The International Electrotechnical Commission (IEC) Technical Committee 57 Working Group 03 (TC57 WG03) was chartered to develop protocol standards for telecontrol, teleprotection, and associated telecommunications for electric utility systems, and it has created IEC 60870-5, a group of five utility-specific protocol standards. IEC 60870-5 specifies a number of links, frame formats, and services that may be provided at each of three layers. IEC 60870-5 uses the concept of a three-layer enhanced performance architecture (EPA) reference model for efficiency of implementation in devices such as RTUs, meters, relays, etc. used in SCADA systems. 

IEC 60870-5 specifies a number of frame formats and services that may be provided at different layers. IEC 60870-5 is based on a three-layer EPA reference model for efficient implementation within RTUs, meters, relays, and other IEDs. Additionally, IEC 60870-5 defines basic application functionality for a user layer, which is situated between the OSI application layer and the application program. This user layer adds interoperability for such functions as clock synchronization and file transfers. The following descriptions provide the basic scope of each of the five documents in the base IEC 60870-5 telecontrol transmission protocol specification set. Standard profiles are necessary for uniform application of the IEC 60870-5 standards. Such profiles have been and are being created. The Standard 101 Profile is described in detail following the description of the applicable standards.

•        IEC 60870-5-1 (1990-02) specifies the basic requirements for services to be provided by the data link and physical layers for telecontrol applications. In particular, it specifies standards on coding, formatting, and synchronizing data frames of variable and fixed lengths that meet specified data integrity requirements.

•        IEC-60870-5-2 (1992-04) offers a selection of link transmission procedures using a control field and optional address field; the address field is optional because some point-to-point topologies do not require either source or destination addressing.

•        IEC 60870-5-3 (1992-09) specifies rules for structuring application data units in transmission frames of telecontrol systems. These rules are presented as generic standards that may be used to support a great variety of present and future telecontrol applications. This section of IEC 60870-5 describes the general structure of application data and basic rules to specify application data units without specifying details about information fields and their contents.

•        IEC 60870-5-4 (1993-08) provides rules for defining information data elements and a common set of information elements, particularly digital and analog process variables that are frequently used in telecontrol applications.

•        IEC 60870-5-5 (1995-06) defines basic application functions that perform standard procedures for telecontrol systems, which are procedures that reside beyond layer 7 (application layer) of the ISO reference model. These utilize standard services of the application layer. The specifications in IEC 60870-5-5 (1995-06) serve as basic standards for application profiles that are then created in detail for specific telecontrol tasks.

Each application profile will use a specific selection of the defined functions. Any basic application functions not found in a standards document but necessary for defining certain telecontrol applications should be specified within the profile. Examples of such telecontrol functions include station initialization, cyclic data transmission, data acquisition by polling, clock synchronization, and station configuration.

7.5 DNP3 Users Group 

The development of DNP3 was a comprehensive effort to achieve open, standards-based interoperability between substation computers, RTUs, IEDs (Intelligent Electronic Devices) and master stations (except inter-master station communications) for the electric utility industry for SCADA systems. Also important was the time frame; the need for a solution to meet today's requirements. As ambitious an undertaking as this was, the objective was achieved. Since the inception of DNP, the protocol has also become widely utilized in adjacent industries such as water/waste water, transportation, and the oil and gas industry.  

DNP3 is based on the standards of the International Electrotechnical Commission (IEC) Technical Committee 57, Working Group 03, who have been working on an OSI 3 layer “Enhanced Performance Architecture” (EPA) protocol standard for telecontrol applications. DNP3 has been designed to be as close to compliant as possible to the standards, as they existed at time of development with the addition of functionality not identified in Europe but needed for current and future North American applications (e.g. limited transport layer functions to support 2K block transfers for IEDs, RF and fiber support). DNP3 has been selected as a Recommended Practice by the IEEE C.2 Task Force; RTU to IED Communications Protocol.  

DNP3 was developed by Harris, Distributed Automation Products. In November 1993, responsibility for defining further DNP3 specifications and ownership of the DNP3 specifications was turned over to the DNP3 Users Group, a group composed of utilities and vendors who are utilizing the protocol.  

DNP3 is an open and public protocol. In order to ensure interoperability, longevity and upgradeability of protocol, the DNP3 User Group has taken ownership of the protocol and assumes responsibility for its evolution. The DNP3 User Group Technical Committee evaluates suggested modifications or additions to the protocol and then amends the protocol description as directed by the User Group members.  

Complete documentation of the protocol is available to the public. The four core documents that define DNP3 are: Data Link Layer Protocol Description, Transport Functions, Application Layer Protocol Description, and Data Object Library (referred to as the "Basic 4 Document"). The User Group also has available to members the document "DNP3 Subset Definitions" which will help implementors identify protocol elements that should be implemented.