NDPL Shiksha Document Contribruted by R.N.KUMAR Subhadip Ray Choudhury

4 Name of the program attended Seminar on “ Understanding IEC Technology ” Followed by practical demo Program conducted by (Agency) M/s Schweitzer Engineering Laboratories ( SEL ) E Mail : Web Site: Duration of the program VENUE One Day on 17 th September’08 Hotel Le Meridian, New Delhi Faculty/Eminent Speakers Mr. Timothy P. Tibbals Senior Product Engineer

4 Program Objectives To understand 1. Protocol & its Objective 2. Overview of Network Protocol & Communication w.r.t SCADA compatibility and Communication w.r.t SCADA compatibility and Control & Protection. Control & Protection. 3. Benefits of IEC Multi-Vender Interoperability 5. Ethernet Switch Networks & Security 6. Protocols & Services within IEC Solutions provided by M/s SEL to meet the requirement of Sub-station & Distribution requirement of Sub-station & Distribution automation automation

4 Key Learning o Electric utilities were among the first entities to embrace data telemetry. o Data telemetry was introduced for monitoring, Control and Protection. o Development in communication, Computer, introduction of Intelligent o Electronic Devices (IED) made information collection easier. o Different manufacturers introduced different rules for communicating and exchanging information among their intelligent devices. o This introduced barriers in communicating with other device manufactured by others.

4 Communication Protocol used inside sub- station

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4 Key Learning What is Protocol ? When Intelligent Devices communicate with each other, there needs to be a common set of rules and instructions that each device follows. A specific set of communication rules is called a protocol. Protocols used in Electrical utilities are as follows: 1)Modbus -- Developed by MODICON, USA during 1976 o An application Layer Protocol ( 7 th Layer of OSI ) o Extensively used in Industrial environment o Used in process bus of sub-station bay ( Relays ) o It operates on master-slave type mode. Lave mode will not typically transmit data without a request from master. 2) DNP 3.0 ( Distributed Network Protocol ) -- Developed by Harris, USA ( Based on earlier work of IEC TC57) DNP 3.0 is an open protocol that was developed to establish interoperability between RTUs, IEDs (Intelligent Electronic Devices) and master stations

4 3) IEC series -- IEC Tele-control equipment and systems It is bit serial communication standards. The standard is optimised for efficient and reliable transfer of process data and commands to and from geographically widespread systems over low-speed (up to 64 kbps) fixed and dial-up connections. IEC Standard for Basic Tele-control Transmission Protocol IEC Standard for informative Interface of Protection Equipment IEC Standard for Network access for IEC IEC Protocolfor Inter-control center communication for Tele-Equipment & System This is a protocol which provides High integrity, Efficient data transmission and protection against undetected transmission errors. SCADA is supported by IEC ) UCA ( Utility Communication Architecture ) – IEC series – IEC ( Communication networks and systems in substations ) This standard unifies UCA with European standard. It aims to design a communication system that provides interoperability between the functions to be performed in a substation.

4 Basic Features – IEC o High Speed Data Exchange: Ethernet links operating at 100 Mbit/s exchange polled data and commands between devices at a far faster rate than traditional serial/ field bus protocols. Clients (master stations) can perform supervisory control with negligible delay. Client-Server replaces Master- Slave communications and allows simultaneous access of several clients to the same server. o Peer-to-Peer Communication: Since all Intelligent Electronic Devices (IEDs) within the substation can communicate with each other using reliable high-speed peer-to-peer communications, extensive hardwiring in equipment bays is eliminated and the cost of implementing advanced distributed protection and control schemes is significantly reduced. Generic Substation Event (GSE) messages can be used for interlocking, disturbance recording, cross-triggering, breaker failure protection tripping, directional comparison bus protection and many other advanced applications. o Process Bus Interface: Analog interface units (or Merging Units) located in the substation yard interface with conventional or non-conventional instrument transformers and send the sampled current and voltage values over fiber, thus significantly reducing (actually eliminating) the copper wires between the substation primary equipment and the protection, control and measuring devices. o Standard Bay Schemes: Standard protection and control bay schemes can be engineered and customized to suit the application in software, using GSE logic, thus achieving economical solution. o True Interoperability : The self-descriptive nature of IEC compatible IEDs means that system integration and commissioning is easier.

4 Benefits o Cost effective solution due to reduced inter-wiring o Flexible programming allowing relays and new protection functions to be added without affecting physical wiring o No external protocol converters are required Various venders viz. SEL, AREVA,SIEMENS have provided solutions that allow the migration from conventional or different legacy substation automation systems to IEC based SAS. Relays which have already been delivered with UCA2 on Ethernet can be easily upgraded to IEC 61850, while relays that support other communication protocols can be integrated using "proxy" servers. Protocols used for protection IED by various vendors VenderProtcol ABBSPA / LON GEMODBUS / DNP 3.0 AREVAIEC 103 RETROLLEIEC 103 SCHNEIDERMODBUS

4 GOOSE & GSSE Peer - to - Peer messaging is accomplished with two compliant messages ( GOOSE & GSSE ) that differ slightly, are collectively referred to as GSE. The standardization of GSE messages ensures interoperability directly between IED’s for protection, interlocking & automation. GOOSE : Generic Object Oriented Sub-station Events GSSE : Generic Sub-station Status Events GOOSE is for high speed control messages. Sends messages continuously. Each GOOSE message is dealt separately and at different rate depending upon what is happening, hence transmission time may differ. SCL Files : Sub-station Configuration Language Files, based on XML based configuration Language. SSD Files : System Specification description Files, contains details of SLD, Logical Nodes & their type. ICD Files – These files contains IED description, map IED’s with Logical devices.

4 OSI 7 Layer Model Functionality of different layers o Application Layer: This provides the interface and services that support user application. Ex. , WWW, SMTP. o Presentation Layer: This layer responsible for data encryption, data compression.Ex JPG, MPEG etc o Sessions Layer: Responsible for setting up the communication link and manages the sessions. It could provide connection oriented and connectionless services. o Transportation Layer: Responsible for flow control, Packet size, error free delivery with proper sequence. o Network layer: Route determination takes place in this layer. Translation of IP address to physical address ( NIC) also takes place here. o Data link layer : Responsible for data movement across the actual physical link. o Physical Layer: It defines the physical aspect of how the cabling is hooked.

4 Basic Abbreviations Used IP – Internet Protocol TCP– Transmission Control Protocol UDP – Users Datagram protocol DNP – Distribution Network Protocol LAN – Local Area Network WAN – Wide Area Network HMI – Human Machine Interface GUI – Graphical Users Interface OSI - Open System Interconnection, a reference model for computer to computer data communication. UCA – Utility communication Architecture MMS– Manufacturing Message Specifications ACSI – Abstract Communication Service Interface SCSM – Specific Communication Service Mapping GOOSE - Generic Object Oriented Sub-station Events GSSE - Generic Sub-station Status Events BCU – Bay Control Unit BMU – Bay Monitoring Unit BPU – Bay Protection Unit SCU – Station Control Unit

4 Application Application of Learning in Participant’s Area of Responsibility Today is the demand of utility users & manufacturers to merge the communication capabilities of all IED’s in a sub-station or even across the entire power network through Wide Area Network (WAN). Most of the utilities have already installed IED’s which provides centralized sub-station control & monitoring. A big amount of information collected in these IED’s remains unused because of traditional integration technique designed exclusively to support SCADA. Protocol IEC has been created as an international standard for communication & integration for the systems built up from multi vender IED’s networked together to perform Protection, Monitoring, Automation, Metering & Control. This standard has been developed for communication & integration of Power system Control equipment and Systems viz. Supervisory Control and Data acquisition ( SCADA ), Energy Management System (EMS), Distribution Management System ( DMS ), Distribution Automation ( DA ), Tele-protection & associated communication for a sub station. It has built-in capability for high speed control and data sharing over the communication network, eliminating a lot of dedicated hard wiring & communication channels with security which is essential in substations today. The protection relays integrate with the PACiS substation control systems over the IEC Substation Bus and at the same time can interface with vendors Merging Units over the IEC Process Bus. Possible application areas in NDPL other than Participant’s Area All the Fifty four 66 / 33 / 11 kV NDPL Grid sub-stations, power distribution system, CENNET w.r.t Protection, communication, SCADA, DMS, DA, EMS through WAN & LAN, Fibre optics by integration of this latest technology protocol IEC with existing IED’s with different protocols as supplied by various venders.