Substations Committee working group Master Station Architecture,User on"Applications of New Technologies Developing standards Interface,and Advanced SCADA Con- in Substation Monitoring and Control." The task force is investigating proto- for SCADA systems cepts.The October 1992.January 1993,and April 1993 issues of IEEE cols to determine if there is one that is has been a slow, Computer Applications in Power car- ISO/OSI compliant,and would be difficult process ried articles that were also based on applicable to the various substation parts of the tutorial,and other articles equipment. are being considered for future issues. For distances beyond a few kilometers,efforts are The tutorial was presented at the 1991 Transmission underway to develop standards for metropolitan areas and Distribution Exposition and Conference(with video- (metropolitan area network or MAN)and widely dis- taping by the IEEE Education Activities Department), persed areas (wide area network or WAN).The MAN and the IEEE 1992 Winter and Summer Meetings. standard would be applicable to SCADA,while the WAN To order the tutorial document (91 EH 0337-6 PWR) would be applicable to inter-utility exchange.Impacts on or the videotape (HV0245-1-POT,which includes one present systems are several years away. copy of the document),call IEEE Customer Service,(800) In order to provide a common direction to the U.S 678-IEEE electric utility industry in the area of information exchange,the Electric Power Research Institute (EPRD) For Further Reading has a program underway,the Utility Communication G.Paula,"SCADA/EMS:integrating the Latest Developments into Architecture (UCA).The UCA will be designed to define Utility Systems".Electrical World,Volume 206.Number 12,December an overall architecture for all electric utility applications, 1992. including SCADA systems,power plants,customer inter- IEEE Recommended Practice for Master/Remote Supervisory Control face,inter-utility exchange,etc.(A similar effort in the and Data Acquisition (SCADA)Communications,IEEE Standard 999- 1992. manufacturing industry,the Manufacturing Automation Fundamentals of Supervisory Systems.IEEE Tutorial Course.91 Protocol (MAP),has preceded the UCA effort by about EH0337-6 PWR. 10 years).The use of industry standards within the Definition,Specification.and Analysis of Systems Used for Supervisory architecture layers will also be recommended.This Control.Data Acquisition,and Automatic Control,IEEE Standard.Publi- effort will definitely affect the master/RTU communica- cation ANSI/IEEE C37.1. tions area,but probably not for several years. Utility Communications Architecture:LCA Specification V1.0,EPRI RP2949-1,August 1990,Palo Alto,California. Energy Management System Inter-Utility Communication Guidelines, Acknowledgements Western Systems Coordinating Council.June 1984. This article is based on the "Telecommunications Options"chapter of the IEEE Fundamentals of Supervisory Biographies Systems tutorial course.Other chapters include Introduc- Wayne R.Block is supervisor of the Power System Com- tion and Rational for Supervisory Systems,Remote Termi- puter Applications Group at the Los Angeles Department nal Units,Project Management,Considerations in of Water and Power.He has 25 years experience in the Applying Supervisory Control Systems to Electric Utilities. design of Energy Management Systems,SCADA Systems, and RTU installations.He is a Senior Member of the IEEE and the PES,a member of the Substations Committee Abbreviations and its Data Acquisition,Processing,and Control Sys- tems Subcommittee,and is the chairman of the working AM amplitude modulation group on Applications of New Technologies in Substa- FDM frequency division multiplexing tion Monitoring and Control. FSK frequency shift keying Dennis J.Gaushell,P.E.,is a Senior Member of IEEE HDLC high level data link control protocol IED intelligent electronic device and holds three electrical engineering degrees from LAN local area network Bradley University and Stanford University.He has over MAN metropolitan area network 20 years experience in the control and telecommunica- PSK phase shift keying tions fields,as a system supplier and as a consultant. RTU remote terminal unit Presently.he is president of Westin Engineering,Inc. SBO select-before-operate security provision San Jose,California,where he is responsible for all engi- SCADA supervisory control and data acquisition neering activities in water,wastewater,electric,and gas SOE sequence of events control systems,and telecommunications.He is author TDM time division multiplexing of over 20 technical papers,coauthor of the ANS//IEEE UCA utility communication architecture Standard C37.1-1987 (SCADA Standard),and coauthor of WAN wide area network the "Telecommunications Options"portion of the IEEE Fundamentals of Supervisory Systems tutorial course. 50 IEEE Computer Applications in Power