NDPL
Shiksha Document
Contribruted by
R.N.KUMAR
Subhadip Ray Choudhury
Name of the program attended
Seminar on “ Understanding IEC 61850
Technology ”
Followed by practical demo
Program conducted by (Agency)
M/s Schweitzer Engineering Laboratories ( SEL )
E Mail : info@selinc.com
Web Site: www.selinc.com
Duration of the program
One Day on 17th September’08
VENUE
Hotel Le Meridian , New Delhi
Faculty/Eminent Speakers
Mr. Timothy P. Tibbals
Senior Product Engineer
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Program Objectives
To understand
1. Protocol & its Objective
2. Overview of Network Protocol &
Communication w.r.t SCADA compatibility and
Control & Protection.
3. Benefits of IEC 61850
4. Multi-Vender Interoperability
5. Ethernet Switch Networks & Security
6. Protocols & Services within IEC 61850
7. Solutions provided by M/s SEL to meet the
requirement of Sub-station & Distribution
automation
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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.
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Communication Protocol used inside
sub- station
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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 ( 7th 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
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3) IEC 60870 series -- IEC 60870 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 60870-5-101
IEC 60870-5-103
IEC 60870-5-104
IEC 60870-6
Standard for Basic Tele-control Transmission Protocol
Standard for informative Interface of Protection Equipment
Standard for Network access for IEC 60870-5-101
Protocol
for 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 60870
4) UCA ( Utility Communication Architecture ) – IEC 61850 series – IEC 61850 (
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.
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Basic Features – IEC 61850
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 MasterSlave 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 61850-compatible IEDs means that system
integration and commissioning is easier.
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Benefits
o
o
o
Cost effective solution due to reduced inter-wiring
Flexible programming allowing relays and new protection functions to be added without affecting
physical wiring
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 61850 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
Vender
Protcol
ABB
GE
AREVA
RETROLLE
SCHNEIDER
SPA / LON
MODBUS / DNP 3.0
IEC 103
IEC 103
MODBUS
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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.
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OSI 7 Layer Model
Functionality of different layers
o
Application Layer: This provides the interface and services that support user application. Ex. E-mail,
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.
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Basic Abbreviations Used
IP
TCP
UDP
DNP
LAN
WAN
HMI
GUI
OSI
UCA
MMS
ACSI
SCSM
GOOSE
GSSE
BCU
BMU
BPU
SCU
– Internet Protocol
– Transmission Control Protocol
– Users Datagram protocol
– Distribution Network Protocol
– Local Area Network
– Wide Area Network
– Human Machine Interface
– Graphical Users Interface
- Open System Interconnection , a reference model for computer to computer
data communication.
– Utility communication Architecture
– Manufacturing Message Specifications
– Abstract Communication Service Interface
– Specific Communication Service Mapping
- Generic Object Oriented Sub-station Events
- Generic Sub-station Status Events
– Bay Control Unit
– Bay Monitoring Unit
– Bay Protection Unit
– Station Control Unit
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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 61850 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
61850 8-1 Substation Bus and at the same time can interface with vendors Merging Units over the
IEC 61850 9-2 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 61850 with existing IED’s with different protocols as supplied by
various venders.
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