ICS ; NRS 037-3:2005. ISBN Edition 1 TELECONTROL PROTOCOL. Part 3: Intercontrol centre communications protocol N R S

Transcription

1 ICS ; NRS 037-3:2005 ISBN Edition 1 TELECONTROL PROTOCOL Part 3: Intercontrol centre communications protocol N R S

2 This rationalized user specification is issued by the Technology Standardization Department (TSD), Eskom, on behalf of the User Group given in the foreword and is not a standard as contemplated in the Standards Act, 1993 (Act No. 29 of 1993). Table of changes Change No. Date Text affected Correspondence to be directed to Printed copies obtainable from The NRS Projects Manager Standards South Africa The Technology Standardization Department (TSD) Private Bag X191 Eskom Pretoria 0001 PO Box 1091 Johannesburg 2000 Telephone : Fax : sales@sabs.co.za Website: Website : COPYRIGHT RESERVED Printed in the Republic of South Africa by Standards South Africa 1 Dr Lategan Road, Groenkloof, Pretoria

3 NRS 037-3:2005 Foreword This part of NRS 037 was prepared on behalf of the Electricity Suppliers Liaison Committee (ESLC). This part of NRS 037 was prepared by a working group which, at the time of publication, comprised the following members: MC Giddey (Chairman) GS Anderson V Batohi J Botha K Botha K Brown A de la Guerre D Gutschow R Harrichunder L Huntley PA Johnson (Project Leader) S Mbanga J Mostert I Naicker A Perera J Rossouw K Singh SJ van der Berg I van der Merwe P Vermeulen City of Cape Town Nelson Mandela Metropolitan Municipality ethekwini Electricity Eskom (Transmission) Ekurhuleni Metropolitan Municipality Eskom (Resources and Strategy) Eskom (Transmission) Eskom (Resources and Strategy) ethekwini Electricity City Power Johannesburg Eskom (Resources and Strategy) Eskom (Distribution) City of Cape Town Eskom (Transmission) Technology Services International City of Tshwane Eskom (Resources and Strategy) Mangaung Municipality (Centlec) Eskom (Transmission) City Power Johannesburg NRS 037 consists of the following parts, under the general title Telecontrol protocol: Part 1: Telecontrol protocol for stand-alone remote terminal units. Part 2: Telecontrol protocol for integrated substation control (In course of preparation). Part 3: Intercontrol centre communications control.

4 NRS 037-3:2005 Introduction This part of NRS 037 has been prepared to establish and promote uniform requirements for intercontrol centre communications protocol used on electricity supply authorities telecontrol systems, for application in the South African Electricity Supply Industry. This part of NRS 037 is intended for use by the following: a) electrical utilities in South Africa with the need to transfer real-time data to other utilities or to another control centre who are looking for information on which protocol to implement; b) electrical utilities in South Africa that have decided to use TASE.2 as their intercontrol centre communications protocol and are looking for additional information on what to specify; and c) vendors operating within the South African electricity utility environment looking for information on how to best serve the industry with respect to intercontrol centre communications protocols and their implementation. There is a growing requirement for the ability to be able to perform intercontrol centre communication and consequently for a standard protocol to be agreed upon nationally. Since electrical networks are by their nature interconnected, interutility and intercontrol centre real-time data exchange is very desirable. The ability to exchange power system data across boundaries provides visibility for disturbance detection and reconstruction, improved modelling capability and enhanced operation. Previously, intercontrol centre communication was only really possible through the application of proprietary protocols and systems, but with recent developments TASE.2 provides an international standard for real-time exchange within the electricity power utilities industry. TASE.2 is specified in parts and sections of IEC and is based on TCP/IP and MMS, which is also the basic approach used for IEC 61850, the international standard for substation automation. Thus the medium to long-term vision of IEC TC 57 are integrated control systems that are based on IEC The Electricity Suppliers Liaison Committee expresses the wish that all supply authorities will adopt the text of this part of NRS 037 in so far as their particular conditions will permit. Any differences between the requirements of this part of NRS 037 and the purchaser's requirements should, as far as possible, be clearly indicated in schedules and, where appropriate, be submitted for consideration in future revisions of this part of NRS 037. Keywords control, control centres, data communication, data link, intercontrol centre, protocol, RTU, SCADA, TASE.2, telecontrol.

5 1 NRS 037-3:2005 Contents Page 1 Scope Normative references Terms, definitions and abbreviations Requirements Protocol TASE.2 overview Conformance blocks and services Recommended implementation Profiles Application of TASE Testing for interoperability... 8 Bibliography... 9

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7 3 NRS 037-3:2005 TELECONTROL PROTOCOL Part 3: Intercontrol centre communications protocol 1 Scope This part of NRS 037 covers intercontrol centre communications protocol based on TASE.2, and provides recommendations on the minimum implementation of TASE.2. 2 Normative references The following documents contain provisions which, through reference in this text, constitute provisions of this part of NRS 037. All documents are subject to revision and, since any reference to a document is deemed to be a reference to the latest edition of that document, parties to agreements based on this part of NRS 037 are encouraged to take steps to ensure the use of the most recent editions of the documents listed below. Information on currently valid national and international standards can be obtained from Standards South Africa. IEC , Telecontrol equipment and systems Part 6-503: Telecontrol protocols compatible with ISO standards and ITU-T recommendations TASE.2 services and protocol. IEC , Telecontrol equipment and systems Part 6-505: Telecontrol protocols compatible with ISO standards and ITU-T recommendations TASE.2 User guide. IEC , Telecontrol equipment and systems Part 6-702: Telecontrol protocols compatible which ISO standards and ITU-T recommendations Functional profile for providing the TASE.2 application service in end systems. IEC , Telecontrol equipment and systems Part 6-802: Telecontrol protocols compatible with ISO standards and ITU-T recommendations TASE.2 Object models. 3 Terms, definitions and abbreviations For the purposes of this part of NRS 037, the following terms, definitions and abbreviations apply. NOTE A glossary of some other terms used in telecontrol is given in annex A of NRS Terms and definitions control centre master station central station responsible for the monitoring and control of an electricity utility power network protocol stack defined implementation of the communication layers in a protocol

8 NRS 037-3: system configuration specified arrangement of telecontrol stations and their interconnections TASE.2 TASE based on the ICCP model 3.2 Abbreviations ACSE: ATM: CLNP: EMS: FDDI: FR: ICCP: IEC: IED: ISDN: LAN: LLC: MMS: OSI: Application Control Service Element Asynchronous Transfer Mode Connectionless Network Protocol Energy Management System Fibre Digital Data Interface Fixed Routing Intercontrol Centre Communications Protocol International Electrotechnical Commission Intelligent Electronic Device International Standard Data Network Local Area Network Link Layer Control Manufacturing Message Specification Open System Interconnection RDBMS: Relational Database Management System RTU: SCADA: SDH: TCP/IP: WAN: Remote Terminal Unit Supervisory, Control and Data Acquisition Synchronous Digital Hierarchy Transmission Control Protocol/Internet Protocol Wide Area Network 4 Requirements 4.1 Protocol The protocol to be used for intercontrol centre communications shall be TASE.2, as specified in the following sections of IEC : a) IEC ; b) IEC ;

9 5 NRS 037-3:2005 c) IEC ; and d) IEC TASE.2 overview TASE.2 maximizes the use of existing standard protocols in all layers except for the application layer of the OSI reference model. This means that new protocol development for the implementation of TASE.2 is only necessary in the upper layer of layer 7. Control centre applications are at the top. Manufacturing Message Specification (MMS) is used for specifying the mechanics of naming, listing and addressing variables and for message control and interpretation. Application Control Service Element (ACSE) is used to establish and manage logical associations or connections between sites. TASE.2 relies on the ISO presentation layer 6 and session layer 5 as well for its operation. As a result of the protocol architecture (see figure 1), TASE.2 is independent of the lower layers, so that as new protocols evolve in the lower layers, TASE.2 will be able to benefit from them with very limited changes necessary. Application ICCP IEC IEC MMS ACSE Presentation ISO Presentation Session ISO Session Transport ISO Transport Class 4 TCP Network ISO CLNP IP Data link ISO/IEC LLC, FDDI, FR, ISDN, etc. Physical Ethernet LAN, WAN, Point-to-Point Circuit, ATM, SDH, etc. Figure 1 TASE.2 protocol architecture 4.3 Conformance blocks and services Overview From a user perspective, conformance blocks are one of the most important aspects of TASE.2. Nine conformance blocks (see table 1) have been defined which contain groups of objects which have been selected and grouped with the objective of providing a specific service. Users, therefore, need only identify the broad type of service requirement that they have and selection of the appropriate conformance block should ensure that all the objects required to support that service will be provided Services provided A high-level overview of the main services offered by the nine conformance blocks is given in to The services and protocols associated with each conformance block and its associated objects are discussed in IEC Each conformance block represents a specific function or set of functions that a utility might wish to implement.

10 NRS 037-3: Conformance block 1 Periodic Power System Data Block 1 is slightly different from all the other blocks. Block 1 is the minimum that a developer can implement. It is also the minimum that a user can purchase. Block 1 provides for the periodic transfer of power system data. Power system data is the data associated with field devices status (e.g. breakers), analogue values (e.g. megawatts, voltage, current, etc.) and accumulator values (e.g. kwh). Each data item may also have a quality code that provides information about the reliability of the data item itself. Table 1 Conformance blocks and services provided 1 2 Block Service provided 1 Periodic Power System Data 2 Extended Data Set Condition Monitoring 3 Block Data Transfer 4 Information Messages 5 Device Control 6 Program Control 7 Event Reporting 8 Additional User Objects 9 Time Series Data Conformance block 2 Extended Data Set Condition Monitoring Block 2 is used to enable the transfer of power system data in additional ways rather than just periodic reports. A periodic report, although very simple, has the drawback that it will report every value every time it reports which is clearly not very bandwidth efficient. Block 2 allows for report-byexception reporting (RBE). Report-by-exception allows for reporting to only take place when a change takes place or as a result of integrity polling Conformance block 3 Block Data Transfer Block data transfer is not commonly used but is intended to reduce the bandwidth requirements. Data blocking involves power system data being reported with fewer bytes required for sending the full message encoding as used for blocks 1 and 2. The consequence of blocking is that the information needed to properly decode the data is not all contained in the message reported. This approach can be useful where bandwidth is at a premium The following two mechanisms are used to achieve efficiency: a) dropping the tag and length fields for each data value reported; and b) the creation of an index-based tagging scheme to replace variable names Conformance block 4 Information Messages Block 4 provides a general message transfer mechanism that also includes the ability to transfer ASCII text or binary files. These messages might be simple formatted ASCII text messages with data from the SCADA/EMS incorporated into the body of the message. The messages could be used as alarm text or text reports for display on a receiving operator console or for logging.

11 7 NRS 037-3: Conformance block 5 Device Control Block 5 provides a mechanism for transferring a "request to operate a device" from one TASE.2 implementation to another. TASE.2 does not directly control the device but communicates a client s request to operate a device to the server. TASE.2 supports select and validate before operation for interlocked devices and the armed-for-execution mode for a selected device. The server notifies the client that the command was successfully received by the end device but the only way to determine if the operation was successfully completed or not is to scan the indication point associated with the control point Conformance block 6 Program Control Block 6 provides a mechanism for a TASE.2 client to perform program control at a server. Program control is only possible when agreed upon before between the two sites Conformance block 7 Event Reporting Block 7 allows for the provision of Event Enrolment and Event Conditions. This provides for extended reporting of system events occurring at a remote site and is essentially a form of event logging Conformance block 8 Additional User Objects Block 8 provides a utility with a number of additional data objects relating to transferring scheduling and accounting information and power plant information. A vendor might offer support for one or more of the data objects in block Conformance block 9 Time Series Data Block 9 provides a TASE.2 client with the ability to receive time series data. Time series data might be data that has a required sampling time too fast to conveniently transfer it continuously between the two TASE.2 implementations and is not needed at the client site in real-time. Real-time trending of values is a possible example. In using time series data, the client needs to specify a begin and end time. If these are in the past, the report can be immediately generated. 4.4 Recommended implementation The recommended minimum implementation is as given in table Profiles Table 2 Recommended minimum implementation 1 2 Block Service provided 1 Periodic Power System Data 2 Extended Data Set Condition Monitoring 4 Information Messages 5 Device Control It is possible to use TASE.2 with one or both of the following two protocol profiles: a) OSI; and b) TCP/IP.

12 NRS 037-3: TASE.2 was originally designed for operation over the ISO OSI seven layer protocol stacks and this has been widely implemented. Depending on the implementation specifics, it may be possible to implement TASE.2 over TCP/IP. If a utility already uses TCP/IP, it is recommended that TASE.2 be used over TCP rather than introducing a full OSI stack. It is possible for utilities to run both stacks in parallel. Consultation with the vendor involved is recommended. 4.6 Application of TASE The TASE.2 user guide, IEC , should be referred to when TASE.2 is being applied. In particular, clause 18 of IEC recommends that when TASE.2 is specified in procurement, the requirements in shall also be specified. This is a result of aspects of TASE.2 which are defined as local implementation issues and which are left to the vendor to implement as he (the vendor) feels fit The following requirements shall be specified: a) a network diagram that shows all network requirements between TASE.2 nodes; b) the system configuration at each TASE.2 node to identify all computer system interfaces from SCADA databases, RDBMS, power applications, or operator consoles to each TASE.2 server; c) system requirements, such as 1) sizing, 2) performance, 3) availability, 4) backup and recovery (including whether redundant TASE.2 servers are needed and failover schemes required), and 5) the use of certain corporate standards; d) functional requirements, such as which TASE.2 conformance blocks are needed, which specific TASE.2 data objects are needed, definitions of any new data objects to handle the required data transfers, API needs, security required, the number of associations and the intended use of each, user interface (such as for Bilateral Table creation and editing, Data Set creation and editing, and network management); e) hardware requirements, such as the use of specific platforms, routers, LAN hub technologies, etc.; f) support software requirements, such as standards to be followed, operating system, programming languages, editor and program development support tools, etc.; and g) project implementation requirements, such as project deliverables, customer and vendor responsibilities, project management guidelines, quality assurance provisions, testing, commissioning, warranty, maintenance support, documentation, and training. 5 Testing for interoperability A number of TASE.2 systems have been internationally tested together in terms of interoperability. It is recommended that details of testing performed be requested from the applicable vendor(s). Depending on the information available, utilities should decide if they want to perform additional testing or to what extent it may be necessary.

13 9 NRS 037-3:2005 Bibliography ISO/IEC , Information technology Telecommunications and information exchange between systems Local and metropolitan area networks Specific requirements Part 2: Logical link control. ISO/IEC 9506 (all parts), Industrial automation systems Manufacturing message specification. NRS 037-1, Telecontrol protocol Part 1: Telecontrol protocol for stand-alone remote terminal units. etz-report 32. Open communication platforms for telecontrol applications: benefits from the new standard IEC TASE.2 (ICCP). Available from World Wide Web: < Standards South Africa