Scadasubstationautomation

2011

A PROJECT
REPORT ON
SUBSTATION
AUTOMATION
Project report submitted to BSES New Delhi for
6 weeks Industrial Training. Enrolled in RAJASTHAN
TECHNICAL UNIVERSITY(INSTITUTE OF ENGINEERING &
TECHNOLOGY,ALWAR).

MAHESH KUMAR YADAV
B.TECH 4TH YEAR
ROLL NO-08EIAEE030
1
ELECTRICAL:2008-12

SUBSTATION AUTOMATION

PREFACE

This report prepared during training is life’s greatest learning experience, as it is full of
observation and knowledge. This period also provide a chance to give theoretical knowledge
into a practical shape. Most importantly we have been given the exposure to the latest
technology in the world of SCADA. This report is a result of five weeks training that we are
having in BSES, New Delhi. Joining BSES as a trainee gave me a solid platform in the beginning
of my professional career.

We whole heartedly thank the company as well as their SCADA team for giving us the
opportunities to work on the latest technology and bring out the best in us and developing our
talents, not only in the technical field but also how to work in a team. Co-operating and
assisting each other in the department helped us to explore potential and perform much
better.

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ACKNOWLEDGEMENT

A training of such a comprehensive coverage cannot be realized without help from numerous
sources and people in the organization.

I am thankful to Mr. S.S. Sondhi, for providing necessary facility to carry out my training successfully.

I like to take this opportunity to show my gratitude towards Mr. Tanmay Mal
who helped me in bringing the project to its present form. They have been a motivator
& source of inspiration for me to carry out the necessary proceedings for the project to be
completed successfully.

Finally I would like to take this opportunity to thank the organization, BSES who helped me to
acquire proper knowledge and success in my training.

I shall cherish the memories of the co-operation and help extended by the staff of this
organization to a trainee and shall feel honored if I could be of any help to this organization.

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TABLE OF CONTENTS

1. Company Profile- Page 1

2. About the Project (SCADA)- Page 11

3. Remote Terminal Unit (RTU560A)- Page 18

4. Communication Subsystem- Page 27

5. Control Centre Subsystem- Page 38
a) Work Station or Control Room-Page 38

b) Communication Room – PCU 400- Page 46

6. SCADA advantages- Page 48

7. Bibliography- Page 49

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COMPANY PROFILE

BSES Limited is India’s premier utility engaged in the generation, transmission and distribution
of electricity. Formerly known as Bombay Suburban Electric Supply Limited, it was
incorporated on 1st October 1929, for the distribution of electricity in suburbs of Mumbai, with
a pioneering mission to make available uninterrupted, reliable, and quality power to customer
and provide value added services for the development of power and infrastructure sectors.

BSES was amongst the first utilities in India to adopt computerization in1967 to meet the
increasing work load and to improve services to its customers.

As a part of active support to the privatization process, BSES has acquired an equity of 51% in
Delhi’s power sector and unbundling of the Delhi Vidyut Board in July 2002, the business of
power distribution was transferred to BSES Yamuna Power Limited (BYPL) and BSES Rajdhani
Power Limited (BRPL). These two of the three successor entities distribute electricity to 25 lakh
customers spread across 950 sq-km area – 70% of Delhi’s geographical area.

Delhi’s tryst with power privatization has shown brilliant results. The unparalleled
achievements of the electricity distribution sector in Delhi stand out as the most “successful
experiment and replicable model” of Public-Private-partnership (PPP). This view has been
upheld repeatedly by ICRA and CRISIL for the Ministry of Power, Govt. of India.

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DELHI POWER NETWORK DIAGRAM

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ROAD MAP TO PRIVATISATION

The power situation in Delhi till a few years ago was yet another example of man’s incapacity
to handle another form of energy. The Delhi Vidyut Board (DVB) was a State Electricity Board
set up in 1997 under the Electricity (Supply) Act, 1948, succeeding the Delhi Electricity Supply
Undertaking (DESU) which has existed since 1957 as a wing of the Municipal Corporation of
Delhi. It was an integrated utility with generation, transmission and distribution functions
serving all of Delhi except the NDMC and MES (Cantonment) areas to which it supplied power
in bulk.

The creation of DVB, replacing DESU, is 1997 proved to be merely a change in the legal status
of the organization and was not followed by any real change in its structure, functioning and
work culture. Its reputation continued to deteriorate and its poor commercial performance,
the best known thing about DVB perhaps being its high Transmission and Distribution (T&D)
losses made it a drain on the public exchequer. Further, failure in raising the resources
necessary for improvement of its services made matters critical. There were unprecedented,
widespread expressions of public discontent during the difficult summer of 1998.

In December 1998 when the present Government came to power in Delhi, the power situation
was grim to say the least. With T & D losses as high as 50% regular power cute for 10 to 15
hours and Delhi Vidyut Board accumulating liabilities of over Rs. 23,000 crores, Delhi
Government had to come up with a fast and viable alternative. An alternative that would not
only meet people’s aspirations in terms of its end result but also be interesting enough for
investors. And thus began a step by step process of a never-before fundamental power
reform.

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Delhi Electricity Board Regulatory Commission (DERC) was constituted in May 1999 whose
prime responsibility was to look into the entire gamut of existing activity and search for
various ways of power sector reforms. The DERC is even today a fully functional body which
has since issued tariff orders for annual revenue requirement. Delhi Electricity Reform
Ordinance, 2000 was a body which was promulgated in October 2000 and notified in the form
of an Act in March 2001. It mainly provides for the constitution of an Electricity Regulatory
Commission, unbundling of DVB into separate generation, transmission and distribution
companies and increasing avenues for participation of private sector.

This was followed with a Tripartite Agreement which was signed by the Government of Delhi,
DVB employees to ensure the cooperation of stakeholders in this reform process. The
tripartite agreement sent off very positive vibes to the people in general as well as to the
investor community about the sincere and hassle-free objectives of power reforms.

Next, a two stage competitive bidding process of Request for Qualification (RFQ) and Request
for Proposal (RFP) was set into motion for privatization of the distribution companies.

The bidders were selected on the basis of reduction of total Aggregate Technical and
Commercial of losses (AT & C) a unique feature of the power sector reforms in Delhi. The
bidders were required to bid on the basis of efficiency improvement like reduction of AT & C
losses that they achieve year wise over a period of five years.

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On July 1, 2002, The Delhi Vidyut Board (DVB) was unbundled into six successor
companies: Delhi Power Supply Company Limited (DPCL)- Holding Company; Delhi Transco
Limited (DTL) - TRANSCO; Indraprastha Power Generation Company Limited (IPGCL) -
GENCO; BSES Rajdhani Power Limited (BRPL) - DISCOM; BSES Yamuna Power Limited (BYPL) -
DISCOM; North Delhi Power Limited (NDPL) - DISCOM.

The Government handed over the management of the business of electricity distributions to
their private companies BRPL , BYPL and NDPL since July 1, 2002 with 51% equity with the
private sector.(DVB itself was the successor entity to the Delhi Electricity Supply Undertaking
(DESU).

Of these five companies, BRPL, BYPL and NDPL are joint ventures between the Delhi
Government and the private sector which handle the power distribution sector in Delhi. BRPL
is responsible for distribution of power in Central, South and West Delhi. BYPL handles power
distribution in East Delhi (Trans-Yamuna). NDPL distributes power in North and North-West
Delhi. The remaining two companies, DTL and IPGCL, are wholly owned by the Delhi
Government. Delhi Transco Limited is a 'State Transmission Utility of the National Capital of
Delhi', whereas IPGCL is responsible for power generation.

Over the years, DTL has evolved as a most dynamic performer, keeping pace with the many-
fold challenges that confront the ever increasing demand-supply-power-situation and
achieving functional superiority on all fronts. The Transmission losses have been brought down
from 3.84% in 2002-03 to 0.83% in 2006-07, and are the lowest in the country. Delhi, being the
capital of India and the hub of commercial activities in the Northern Region, coupled with the
prosperity of population, the load requirement has been growing at a much faster pace.
Added to that, being the focus of socio-economic and political life of India, Delhi is assuming
increasing eminence among the great cities of the world. Plus the vision-2021, aiming to make
Delhi a global Metropolitan and world class city demands greater infrastructure to enrich
many services of infrastructure development.

DTL has been responsibly playing its role in establishing, upgrading, operating and maintaining
the EHV (Extra High Voltage) network. DTL has also been assigned the responsibility of running
the State Load Dispatch Centre which is an apex body to ensure integrated operations of
power systems in Delhi.

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BSES
(RAJDHANI & YAMUNA)

BSES (Brihan- Mumbai sub-urban electricity supply) is an electricity distribution company
supported by Reliance Energy.

BSES is responsible for electricity distribution only. It can contribute no more than it receives
power from the generating stations in Delhi and the Northern grid. To provide reliable and
quality power supply to its consumers, the company has been divided into two branches that
are BSES-YAMUNA and BSES-RAJDHANI.

BSES-RAJDHANI looks over the electricity distribution to West and South Delhi. Whereas BSES-
YAMUNA is responsible for electricity distribution to Central and East Delhi .

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BSES Yamuna Power Limited

Covers East & Central regions

1. Yamuna Vihar
2. Krishna Nagar
3. Chandni Chowk
4. Paharganj
5. Nand Nagri
6. Mayur Vihar
7. Daryaganj
8. Jhilmil
9. Laxminagar
10. Shankar Road

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BSES Rajdhani Power Limited

Covers South and West regions

1. Nehru Place
2. R K Puram
3. Vikaspuri
4. Najafgarh
5. Alaknanda
6. Mehrauli
7. Palam
8. Nangloi
9. Nizamuddin
10. Janakpuri
11. Punjabi Bagh

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DELHI DISTRIBUTION NETWORK

The existing RELIANCE ENERGY distribution network in DELHI is being operated at 66 KV/33
KV/11 KV and 0.415 KV, with bulk supply at 66 KV/33 KV/11 KV voltage levels available from
TRANSCO.

Presently Delhi network is operated sub-optimally and is predominantly manual at a local level
based on instructions conveyed from the central location at Balaji Estate through telephone /
VHF radios. The decision making at the central location is based on wall mounted static mimic
diagrams of the primary network.

Delhi draws power from 400kv Northern Grid at 400/220kV stations. Delhi’s transmission
system at 220kV consists of twenty three 220kV interconnected sub-stations.

The powers from these 220/66 kV & 220/33 kV sub-stations of Transco are fed to RELIANCE
ENERGY Delhi area through 20 injection points at 66kV & 33 kV voltage level, which are further
distributed to local transformers which step down the 66kV & 33kV to 11kV which is further
directly fed to industries and the local feeders where further the 11kV is step down to 440V for
house hold appliances.

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WHAT IS SCADA?

SCADA stands for supervisory control and data acquisition. It generally refers to an industrial
control system: a computer system monitoring and controlling a process. The process can be
industrial, infrastructure or facility-based as described below:

 Industrial processes include those of manufacturing, production, power
generation, fabrication, and refining, and may run in continuous, batch, repetitive, or
discrete modes.
Infrastructure processes may be public or private, and include water treatment and

distribution, wastewater collection and treatment, oil and gas pipelines, electrical power
transmission and distribution, Wind Farms, civil defense siren systems, and large
communication systems.
Facility processes occur both in public facilities and private ones, including buildings,

airports, ships, and space stations. They monitor and control HVAC, access, and energy
consumption.

Common system components
A SCADA System usually consists of the following subsystems:

 A Human-Machine Interface or HMI is the apparatus which presents process data to a
human operator, and through this, the human operator monitors and controls the process.

A supervisory (computer) system, gathering (acquiring) data on the process and sending
commands (control) to the process.
Remote Terminal Units (RTUs) connecting to sensors in the process, converting sensor
 signals to digital data and sending digital data to the supervisory system.
Programmable Logic Controller (PLCs) used as field devices because they are more
 economical, versatile, flexible, and configurable than special-purpose RTUs.
Communication infrastructure connecting the supervisory system to the Remote Terminal
Units.


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NEED OF SCADA IN SUBSTATION
What we are doing here is Substation Automation: Following aspects can be considered which
are as follows:-

Requirements for System Operations:

Demand
Availability
Shortfall
System frequency
Capacity of transmission lines and transformers
Loading on transmission lines and transformers
Transformers installed in the system
Reactive loading on the network
Alternative sources

Earlier methods used to acquire data

PLCC network
Wireless VHF sets
P&T /FWP telephones
Load pattern obtained in writing
PTW Book etc...

Limitations of old methods

Outage of telephone / PLCC network
Non-clarity of speech
Human factor
No control on operations

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Huge time required to collect data
No check on improper compliance of instructions
Huge time required to pass instructions

Need for automation

Improve information availability and better visibility
Reduction of Fault Restoration times and adequate response to customer query
Real time and historical data for network analysis

Substation equipments generally are categorized into two domains primary
Equipments and secondary equipments. Primary equipments include transformer,
Switchgear etc, while the secondary equipments include protection, control and
Communication equipments.
Levels of Sub-Station Automation: Sub-station Automation systems comprise three
Levels

The station level: It consists of the station computer with a database, operator’s
workplace, and interfaces for remote communication etc. Station Level functions refer
to the substation as a whole.

There are two classes of station level functions namely the process related station
level function and the interface related station level function.

The Process related functions act on the data from multiple bays or substation
level database. These functions are used to submit the control commands for the
primary equipment (Circuit breakers) and collect the substation data like voltage,
current, power factor etc. from the bay level devices. As described above, each bay
includes one primary equipment such as transformers, feeders etc. Interface related
functions enable interactive interface of the substation automation system to the local
station operator HMI (Human Machine Interface), to a remote control centre or to the
remote monitoring centre for monitoring and maintenance.

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The Bay level: It comprises of all the control and protection units and the process
level with more or less intelligent process interfaces to the field equipments. Extended
implementations show all three levels equipped with IEDs, There is not only vertical
communication between the levels (e.g. between bay and station level), but also
horizontal communication within the level (e.g. in the bay level between bay units for
functions like interlocking).

Bay level functions are using mainly one bay and acting mainly on the primary
equipment of one bay. The definition of bay level functions considers some kind of a
meaningful substructure in the primary substation configuration and related to this
substructure, some local functionality or autonomy in the secondary system.
Examples for such functions are line protection or bay control. These functions
communicate within the bay level and process level.

The Process Level Function: Its main task is to extract the information from
switchgear / CTs / VTs in the substation and to send them to upper level device,
called bay level device. The other major task of process level function is to receive the
control command from bay level device and execute it at appropriate switch level.
The initial advent of digital substations was followed by a rapid evolution of
software technology. Substation automation systems formed out of distributed
components is a technological possibility made viable by the IEC 61850 standard
“Communication Networks and Systems in Substations”.

Substation automation basically consists of implementing intelligent electronic
devices (IEDs) using microprocessors to monitor and control the physical power
system devices. These IEDs can make more data available in digital format. However,
these data can be turned into information that is available in the right form, at the right place,
and at the right time through automation. It is this information that is the true
benefit of substation automation.

Substation automation offers implementation benefits as enumerated below:-

(a) Reduced quantities of equipment, networks implemented with fiber-optic cable, industry
standard interface technology – Ethernet, Data management, Metadata management,
designing toward a seamless architecture, Integration of digital information and functionality,
Gradual displacement of analog devices, new digital equipment capabilities and Station HMI
consoles.
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(b) Substation automation benefits the utility staff, Maintenance staff, Planner, Asset
management personnel, Operators and operational planners, Protection engineers,
Operations engineers, Data administrators.

(c) Substation automation benefits control center operations, SCADA/EMS systems,
Contingency analysis (security analysis), and intelligent alarm processing, Emergency response
etc.

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Relay to Relay Legacy communication Architecture

Each relay to relay requires a dedicated link and change in relay behavior requires
rewiring as shown in figure 3. Also, one cannot know the status of the links if it is
working or not unless it is used. The dedicated application can only access data from
the IEDs. Addition of new device needs modification in the common data path such
as need to add driver specific to the new device, add an entry into tag database and to
modify the application if required.

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SCADA ARCHITECTURE

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REMOTE TERMINAL UNIT

The RTU or the Remote Terminal Unit is one of the components that comprise the SCADA
system. It is located in the field and it acts as an interface between the CR Panels and the
Master Control Center. It gathers information that is present in the field and its sends it to the
MCC. Similarly, it executes the command that come from the MCC. So, we see that it is a two-
way communication device that keeps updating the status of the field continually and
simultaneously executing the commands from the Control Center.

If one takes a closer look at the RTU, one can see two different types of Panels. One, housing a
stack of racks called the “RTU Panel” and the other housing only the MFMS or Multifunction
Meters, called the “MFM panel”.

The RTU panel consists of a

1. Basic Rack
2. Extension Racks

Basic Rack: - The Basic rack or the Communication Sub Rack houses the brain of the RTU. It
consists of a number of slots. Into these slots are inserted a set of “Cards”. The Cards are the
CPUs of the RTU. They help in coordinating the flow of data from and into the RTU. These
CPUs are basically of two types:-

SLI (Serial Line Interface) Cards

The SLI Card acts as an interface between the RTU and the IEDs (Intelligent Electronic Devices).
It continually reads data in and out of the IEDs. These IEDs could either be Numerical Relays
present on the CR Panel or an MFM placed on the MFM panel of the RTU It is generally placed
in a slot of the Basic Rack. The SLI card has got a provision for communicating with the IEDs
through four ports, A, B, 1 and 2. The port A and B are of the RS485 type where 1 and 2 are of
the RS232. The SLI card has an MMI port for handling the dialogue between the web browser
and the RTU.

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ETH (Ethernet) Cards

The ETH card controls the process events and communications with the Control Centers. It
continually reads the data from the Extension Racks, the SLI cards and sends it to the control
center. The ETH card has a port “E”, which is used by the RTU to communicate to the Master.
The ETH is connected to the Extension Rack through port A or B, called COM A and COM B. It
also has an MMI port similar to the one present in the SLI card, for handling the dialogue
between the RTU and the web browser.

The ETH and the SLI cards communicate with each other through a dedicated communication
channel present on the back plane of the Basic Rack.

SERIAL LINE INTERFACE 560 ETHERNET ADAPTER 560

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Extension Racks: - The Extension rack is a place, which is used to house the Input/output
Modules of the RTU. Similar to the structure of the Basic Rack, the Extension rack has slots into
which the I/O modules can be inserted (unlike CPUs in the case of Basic Rack). The extension
rack communicates only with the ETH card of the Basic Rack. In cases where there are more
than one extension racks, each communication port of the extension rack is looped with the
one succeeding it. As mentioned before, the extension rack is connected to the ETH through
port A or B, called COM A and COM B.

The I/O or Input/output modules are located in the Extension rack. The function of the Input
Modules is to send the status of the equipment present in the grid station to the MCC. The
function of the output modules is to control the status of the equipment from the MCC. Thus,
we see that the flow of data, in the case of input modules, is from RTU to MCC and from MCC
to RTU in the case of Output modules.

RTU 560 RACKS

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The different type of I/O modules used are the

DI cards – 23BE21
The DI cards have 16 channels, which can be used for indications. If one takes a look at the
front face of the DI card, one can see 16 LEDs. Each LED indicates a particular status at the
field.

AI cards – 23AE21

The AI card on the other hand gives the analog value of the signal. It has 16 channels on which
eight signals can be configured. The input to a channel in the AI card is a 4-20ma dc current,
which is proportional to the range of the analog value.

DO cards – 23BA20

The DO card is used to execute commands that are sent from the MCC. As soon as the DO card
gets a command from the MCC, it sends a pulse of 48v dc to the exciting terminals of the
contactor. As soon as the contactor gets this pulse it closes its contacts and the command gets
executed. There is a contactor dedicated to execute a particular command.

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MFM PANEL: -

The MFM Panel consists of MFMs. On the Panel cutouts are made pertaining to the size of the
MFMs. The MFMs are then inserted into the cutouts and are tightly clamped. As mentioned
before, the MFM is an IED and it communicates with the MCC through the SLI card.

The MFM has 12 terminals to which connections have to be provided.

2 are for auxiliary supply,

4 are for PT secondary, and

6 are for CT secondary.

Apart from these terminals, the MFM has a Communicable port and a port to which a hand
held programmable and display unit can be connected.

The MFM is an IED that can calculate values once the inputs from the secondary of the CTs and
PTs have been given. Each MFM is dedicated to a particular panel, be it, outgoing or incoming.
The MFM calculates and displays values on a hand held programming and display unit. These
values depend on the programmed primary value corresponding to the CT and PT ratio,
pertaining to that feeder.

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Increasing capabilities of decentralized control and closed-loop control solutions allows to run
more functions to be done in the station directly. The RTU560 supports this by own PLC
programs which may use for control tasks on one side and by the capability to communicate
with the external control, protection and monitoring units via serial lines on the other side.
The RTU560 will distribute process information from these units on the demands for station-
and network control to several network control centers (NCC).

The RTU560 is using a set of communication units (CMU) and I/O boards with a good
modularity to build up the RTU configurations optimized for the application and data point
profile in the station. Starting with a configuration for some I/O process data points and one
communication unit for typical small pump stations or ring main unit stations over medium
size stations for distribution up to large stations on transmission grid level.

The engineering work is a relevant cost factor that can be reduced by standardization of the
process data model and the use of state-of-the-art engineering tools. The tool must support all
type of configurations and communication network for telecontrol which are possible by the
RTU560 family and the customers demand for the distributed stations.

Engineering of the process signals for the RTU560 is done by means of only one tool RTUtil
560' for all stations with RTU560 units and projects. Project is here in the definition of a
telecontrol network with several remote stations combined by router stations etc. RTUtil 560
supports process signal routing from a small station on the lowest level up to the highest level
for network control centers (NCC). Typically it includes the conversion from a telecontrol
protocol 'A' to another telecontrol protocol 'B' used on the next level. For example from DNP
3.0 to IEC 870-5-104. RTUtil 560 generates all files requested to run the RTU560 units. To
reduce traveling costs and to get a higher flexibility for configuration extensions or
modifications, RTUtil 560 and the RTU560 concept allows to download the files into the
RTU560 in the stations via INTRANET using WEB browser technology or via the communication
line, when the protocol supports file transfer.

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Features

The telecontrol system RTU560 should be in the position to transmit nearly all kind of process
information, derived from various units in the station, to the control centers and to marshal
commands received from the control centers to the addressed control unit within the station.

Beside the acquisition and processing of the directly parallel wired process signals to the
RTU560 IO-process interface, the RTU560 is designed for the link of serial communication
routes within the station as well to the higher control level. This can be another RTU560 router
station or a network control center. Within the station it is the connection of other existing
additional control, protection or monitoring devices (Intelligent Electronic Devices = IED) via
serial interfaces.

The RTU560 concept allows the economical adaptation to the requested, different serial links
by cascading the communication and processing units (CMU=Communication Unit) according
to the number of needed serial interfaces.

Functional system features of the RTU560 to fulfill the requirements for remote control
stations:
• High functional scope for telecontrol applications functions
• PLC capabilities to execute control and closed loop control applications for pump stations,
hydro power plants, station interlocking for electrical substations, etc..
• Archiving of process and station events in a sequence of events list in the Flash memory.
Accessible via Intranet or equivalent independent network.
• Archiving of Integrated Totals (ITI) and Analog Measured Values (AMI) in the Flash memory.
Accessible via Intranet or equivalent independent network.
• Reading and archiving of disturbance files from protection relays on request of the
protection relay. Reading of the disturbance files by file transfer over a separate
communication network (e.g. Intranet) on user's demand. Independent and direct information
of available new disturbance files in the disturbance file archive to the NCC.
• Possibility to build (engineer) group alarms for the typical alarm messages, beside a PLC
program.
• Marshalling and filtering process events to the connected NCCs . Decoupling transaction
sequences and delay times to the different NCCs by using a separate process data base per
NCC link.
• Remote access for diagnostic purposes via Web-Browser and Internet or Intranet. With
detailed information down to each process signal.
• Integrated HMI (Human Machine Interface ) for process super vision and control. Via Web-
Browser and Internet or Intranet.

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FIG: Typical configuration of a telecontrol system

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COMMUNICATION SUBSYSTEM

There are two types of communication we are using

INTERNAL COMMUNICATION

Server client and server-server communication is in general on a publish-suscribe and event-
driven basis and uses a TCP/IP protocol, i.e. a client application subscribes to a parameter
which is owned by a particular server application and only changes to that parameter are then
communicated to the client application.

ACCESS TO DEVICES

The data server polls the controllers at a user defined polling rate. The polling rate may be
different for different parameters to the data servers. Time stamping of the process
parameters is typically performed in the controllers and this time-stamp is taken over by the
data server. If the controller and communication protocol used support unsolicited data
transfer then the product will support this too. The product provides communication drivers
for most of common PLC’s and widely used field buses, e.g. Modbus. A single data server can
support multiple communication protocols as it has slots for interface cards.

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Figure below shows the protocols used for communication

Modbus
Field Devices like CT, PT, Remote
Relay that is C & R panel Terminal Unit

IEC- 104
(608705104)

TCP/IP

Server PCU

TCP/IP

Work Station

It is connected through several
hundred RTU’s depending
upon the requirements. So
there is continuous flow of
data between RTU and PCU.
This is called hand shaking
mode.

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TYPES OF CONNECTIVITY

Dedicated Links: -

Reserved for a specific use. In communication, a dedicated channel is the line reserved
exclusively for one type of communication. This is same as a leased line or a private line.

a) Leased Line/E1 interface: Leased lines are dedicated circuits provided by Basic Service
Providers (BSPs), which provide permanent connectivity to the Internet. Leased lines
provide the last mile access from the user premises to the ISP. They provide permanent
connection as compared to the temporary connectivity through dialup access. The
quality of the connection is far superior to what is normally available through dialup,
thanks to digital signaling, less noise, fewer exchanges etc.

Leased lines provides a scalable access method, important particularly for organizations
with large user groups, including corporate, banks and financial institutions, educational
and R&D organizations, government, military etc. Starting typically with 64 Kbps, it is
possible to deploy a scalable architecture, with multiples of E1 (2 MBPS) pipes, providing
the necessary bandwidth. In fact, leased access becomes a must for large organizations
in most situations.

b) Optical Fiber Connectivity: An optical fiber is made up of the core (carries the light
pulses), the cladding (reflects the light pulses back into the core) and the buffer coating
(protects the core and cladding from moisture, damage, etc). Together, all of this
creates a fiber optic which can carry up to 10 million messages at any time using light
pulses. Fiber optics is the overlap of applied science and engineering concerned with the
design and application of optical fibers. Optical fibers are widely used in fiber-optic
communications, which permits transmission over longer distances and at
higher bandwidths (data rates) than other forms of communications. Fibers are used
instead of metal wires because signals travel along them with less loss and are also
immune to electromagnetic interference. Reliance Infocomm provides Optical Fiber
Connectivity to BSES.

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c) LMDS (Local Multiple-Point Distribution service): This is a fixed wireless technology
that operates in the 28 GHz band and offers line of sight coverage over distances up to
3-5 kilometers. It can deliver data and telephony services to 80,000 customers from a
single node. LMDS is one solution for bringing high bandwidth services to homes and
offices within the “last mile” of connectivity, an area where cable or optical fiber may
not be convenient or economical. Data transfer rates for LDMS can 1.5 Gbps to 2Gbps,
but more realistic value may average around 38 Mbps(downstream).

SATELLITE LINK:-

a) Very Small Aperture Terminal (VSAT):- VSAT is a satellite communications system
that serves home and business users. A VSAT end user needs a box that interfaces
between the user’s computer and an outside antenna with a transceiver. The
transceiver receives or sends a signal to a satellite transponder in the sky. The satellite
sends and receives signals from an earth station computer that acts as a hub for the
system. VSATs access satellite in geosynchronous orbit to relay data from small remote
earth stations (terminals) to other terminals (in mesh configurations) or master earth
station "hubs" (in star configurations).

VSATs are most commonly used to transmit narrowband data (point of sale transactions
such as credit card, polling or RFID data; or SCADA), or broadband data (for the
provision of Satellite Internet access to remote locations, VoIP or video). VSATs are also
used for transportable, on-the-move (utilizing phased array antennas) or
mobile maritime communications.

b) Leased line: - A leased line connects two locations for private voice and/or data
telecommunication service. Not a dedicated cable, a leased line is actually a reserved
circuit between two points. Leased lines can span short or long distances. They maintain
a single open circuit at all times, as opposed to traditional telephone services that reuse
the same lines for many different conversations through a process called "switching."

Leased lines most commonly are rented by businesses to connect branch offices,
because these lines guarantee bandwidth for network traffic. So-called T1 leased lines
are common and offer the same data rate as symmetric DSL (1.544 Mbps). Individuals
can theoretically also rent leased lines for high-speed Internet access, but their high cost
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(often more than $1000 USD per month) deters most. Fractional T1 lines, starting at 128
Kbps, reduce this cost somewhat and can be found in some apartment buildings and
hotels.

A leased line is service contract between a provider and a customer, whereby the provider
agrees to deliver a symmetric telecommunications line connecting two locations in exchange
for a monthly rent (hence the term lease). It is sometimes known as a 'Private Circuit' or 'Data
Line' in the UK or as CDN (Circuito Diretto Numerico) in Italy. Unlike traditional PSTN lines it
does not have a telephone number, each side of the line being permanently connected to the
other. Leased lines can be used for telephone, data or Internet services. Some
areringdown services, and some connect two PBXes.

A permanent telephone connection between two points set up by a telecommunications
common carrier. Typically, leased lines are used by businesses to connect geographically
distant offices. Unlike dial-up connections, a leased line is always active. The fee for the
connection is a fixed monthly rate. The primary factors affecting the monthly fee are distance
between end points and the speed of the circuit. Because the connection doesn't carry
anybody else's communications, the carrier can assure a given level of quality.

An internet leased line is a premium internet connectivity product, delivered over fibre
normally, which is dedicated and provides uncontended, symmetrical speeds. It is also known
as an ethernet leased line, DIA line, data circuit or private circuit. Reference taken from Vaioni.

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Leased line Technology presently used at BSES, Delhi
The E1 standard is followed in the European countries. The E1 interface provides a 2048 kbps
access rate. It can support up to 32 user channels, each of 64 Kbps access rate, though mostly
only 30 are used as dedicated user channels. The E1 interface supports several mechanisms for
synchronization, error correction and detection, management and performance messages and
signaling.

BSES SCADA PCM MLDN MODEM

OFC MDF
OFC

ROUTER ROUTER

STM-1 LOCAL EXCHANGE SITE END LOCAL

SWITCH MTNL SWITCH

LAN

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VSAT

The BSES use the VSAT satellite link as a backup for its network. HECL is the service provider of
VSAT. The replying time of this satellite link is very high but it is a very reliable link. Low cost
business terminals with small antennas (generally less than 2 meters in diameter) are often
termed Very Small Aperture Terminals (VSAT). These are usually perceived as being two-way
data terminals, though strictly speaking many of the systems used for data broadcast are really
one-way VSAT. Taking the USA as an example, approximately half of all installed VSAT are only
used for one way data links.

Very Small Aperture Terminal (VSAT), is a two-way satellite ground station or a
stabilized maritime VSAT antenna with a dish antenna that is smaller than 3 meters. The
majority of VSAT antennas range from 75 cm to 1.2 m. Data rates typically range from 56
Kbit/s up to 4 Mbit/s. VSATs access satellites in geosynchronous orbit to relay data from small
remote earth stations (terminals) to other terminals (in mesh configurations) or master earth
station "hubs" (in star configurations).

VSATs are most commonly used to transmit narrowband data (point of sale transactions such
as credit card, polling or RFID data; or SCADA), or broadband data (for the provision of Satellite
Internet access to remote locations, VoIP or video). VSATs are also used for transportable, on-
the-move (utilizing phased array antennas) or mobile maritime communications.

Configurations
Most VSAT networks are configured in one of these topologies:

 A star topology, using a central uplink site, such as a network operations center (NOC), to
transport data back and forth to each VSAT terminal via satellite,

A mesh topology, where each VSAT terminal relays data via satellite to another terminal by
acting as a hub, minimizing the need for a centralized uplink site,
A combination of both star and mesh topologies. Some VSAT networks are configured by
 having several centralized uplink sites (and VSAT terminals stemming from it) connected in
a multi-star topology with each star (and each terminal in each star) connected to each
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other in a mesh topology. Others configured in only a single star topology sometimes will
have each terminal connected to each other as well, resulting in each terminal acting as a
central hub. These configurations are utilized to minimize the overall cost of the network,
and to alleviate the amount of data that has to be relayed through a central uplink site (or
sites) of a star or multi-star network.

Initially the use of VSAT antennas at sea was for transmission of television signals. One of
the first companies to manufacture stabilized VSAT antennas was SeaTel of Concord,
California which launched their first stabilized antenna in 1978. Sea Tel dominates the
supply of two-way VSAT stabilized antenna systems to the marine market with almost 72
per cent of the market in 2007 compared with Orbit’s 17.6 per cent. Initially maritime VSAT
was using Single Channel per Carrier - SCPC technology - which suited large volume users
like oil drilling rigs and oil platforms and large fleets of ships from one ship-owner sailing
within one or few satellite footprints. This changed when the company iDirect launched its
IP-based Time Division Multiple Access (TDMA) technology that dynamically allocated
bandwidth to each ship for shared bandwidth, lowering the entry level cost for getting
maritime VSAT installed, which turned out to be of key importance to small-to mid-sized
fleets, and thus to the market acceptance of VSAT.

VSAT’S STRENGTH

VSAT technology has many advantages, which is the reason why it is used so widely today. One
is availability. The service can basically be deployed anywhere around the world. Also, the
VSAT is diverse in that it offers a completely independent wireless link from the local
infrastructure, which is a good backup for potential disasters. Its deployability is also quite
amazing as the VSAT services can be setup in a matter of minutes. The strength and the speed
of the VSAT connection being homogenous anywhere within the boundaries is also a big plus.
Not to forget, the connection is quite secure as they ar private layer-2 networks over the air.
The pricing is also affordable, as the networks themselves do not have to pay a lot, as the
broadcast download scheme (eg. DVB-S) allows them to serve the same content to thousands
of locations at once without any additional costs. Last but not least, most of the VSAT systems
today use onboard acceleration of protocols (eg. TCP, HTTP), which allows them to delivery
high quality connections regardless of the latency.

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VSAT's Drawbacks

As with everything, VSAT also has its downsides. Firstly, because the VSAT technology utilizes
the satellites in geosynchronous orbit, it takes a minimum latency of about 500 milliseconds
every trip around. Therefore, it is not the ideal technology to use with protocols that require a
constant back and forth transmission, such as online games. Also, surprisingly, the
environment can play a role in slowing down the VSATs. Although not as bad as one way TV
systems like DirecTV and DISH Network, the VSAT still can have a dim signal, as it still relies on
the antenna size, the transmitter's power, and the frequency band. Last but not least,
although not that big of a concern, installation can be a problem as VSAT services require an
outdoor antenna that has a clear view of the sky. An awkward roof, such as with skyscraper
designs, can become problematic.

Typical applications for interactive VSAT networks are:
 Computer communications;
 Reservation systems;
 Database enquires;

Billing systems;

 File transfers;
 Electronic mail;
 Video conferencing;
 Point of sale transactions;
 Credit checks and credit card verification;
Stock control and management.

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The most common VSAT configuration is the TDM/TDMA star network. These have a high bit
rate outbound carrier (TDM) from the hub to the remote earth stations, and one or more low
or medium bit rate Time Division Multiple Access (TDMA) inbound carriers.

With its star configuration network architecture, interactive VSAT technology is appropriate
for any organization with centralized management and data processing.

This configuration has been developed to minimize overall lifetime costs for the complete
network including satellite transmission costs. The use of a single high performance hub allows
the use of low cost remote VSAT terminals and optimizes use of satellite capacity. Even so, in
most VSAT networks, the cost of the VSAT terminals usually far exceeds the cost of the hub
(typically a VSAT terminal is 0.1 to 0.2% of the price of the hub).

In a typical VSAT network, remote user sites have a number of personal computers, dumb
terminals and printers connected to the VSAT terminal which connects them to a centralized
host computer either at the organization’s head office or data processing centre. Data sent to
the VSAT terminal from the DTEs is buffered and transmitted to the hub in packets.

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Shared Hub Networks

To make VSAT networks more affordable it is possible to share the hub between several users,
thereby spreading the cost. In this case the hub is usually owned by a service provider who
retains overall control of the network and who manages the hub itself.

Each user, however, is allocated his own time slots or carriers and can so operate his own
private network using the shared hub facility without any loss of privacy. The operation and
management of these sub networks is performed by the users themselves completely
independently of the service supplier.

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CONTROL CENTRE SUBSYSTEM

WORK STATION
Work station is nothing but the control room itself. In BSES there are four monitors which are
used for the display of:

1. Delhi power summary (Delhi SLDC and NRLDC Data’s from web sites)
2. Single line diagram of the grid
3. Alarms and Event list
4. OMS-Outage management

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EVENT LIST
An event list is a historical record of events, chronologically presented, where each event has a
time stamp and a description

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IED INDICATION PAGE

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BUS BAR INDICATIONS

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DESIGNING OF SINGLE LINE DIAGRAMS (DATA
ENGINEERING)

Single line diagram (SLD)

The first step in planning a substation layout is the preparation of a one-line diagram which
shows in simplified form the switching and protection arrangement required, as well as the
incoming supply lines and outgoing feeders or transmission lines. It is a usual practice by many
electrical utilities to prepare one-line diagrams with principal elements (lines, switches, circuit
breakers, and transformers) arranged on the page similarly to the way the apparatus would be
laid out in the actual station.

Incoming lines will almost always have a disconnect switch and a circuit breaker. In some
cases, the lines will not have both; with either a switch or a circuit breaker being all that is
considered necessary. A disconnect switch is used to provide isolation, since it cannot
interrupt load current. A circuit breaker is used as a protection device to interrupt fault
currents automatically, and may be used to switch loads on and off. When a large fault current
flows through the circuit breaker, this may be detected through the use of current
transformers. The magnitude of the current transformer outputs may be used to 'trip' the
circuit breaker resulting in a disconnection of the load supplied by the circuit break from the
feeding point. This seeks to isolate the fault point from the rest of the system, and allow the
rest of the system to continue operating with minimal impact. Both switches and circuit
breakers may be operated locally (within the substation) or remotely from a supervisory
control center.

Once past the switching components, the lines of a given voltage connect to one or
more buses. These are sets of bus bars, usually in multiples of three, since three-
phase electrical power distribution is largely universal around the world.

The arrangement of switches, circuit breakers and buses used affects the cost and reliability of
the substation. For important substations a ring bus, double bus, or so-called "breaker and a
half" setup can be used, so that the failure of any one circuit breaker does not interrupt power
to branch circuits for more than a brief time, and so that parts of the substation may be de-

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energized for maintenance and repairs. Substations feeding only a single industrial load may
have minimal switching provisions, especially for small installations.

Once having established buses for the various voltage levels, transformers may be connected
between the voltage levels. These will again have a circuit breaker, much like transmission
lines, in case a transformer has a fault (commonly called a 'short circuit').

Along with this, a substation always has control circuitry needed to command the various
breakers to open in case of the failure of some component.

Special features include:
Automatic checking of all circuit connections
Automatic assignment of colors to different voltage levels
Zoom in and zoom out facility
Group copying, deletion and movements of objects
Navigation map
Grid layout
Easy location of a user specified equipments
Functions controlled either mouse or keyboard

Designing of single line diagrams is done using software DE400, pad and WS500. Rough design
is done using subnets and bays in DE400. Initial step is to select a subnet for a particular Bus
bar e.g. LT line, HT line. Next, bay is selected for individual elements to be connected with the
bus bar such as circuit breaker, CT & PT, isolators and earthing isolators. It means bay is a
subpart of subnet. For power transformers individual subnets are selected.

Now this image is presented in a pad where further modification is carried out by locating
correct position for spring of circuit breaker, transformer connection etc. and finally it is
placed in WS500.

WS500 is the user interface for the Network Manager system and is a proven tool for the
demanding real-time control of geographically distributed process.

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In addition, by supporting ABB’s industrial IT, the WS500 also performs Aspect and Object
navigation. This adds more flexibility by making it possible to add object-specific user
functionality.

WS500 features:
State of the art Microsoft Windows look and feel with Multi Document Interface (MDI)
support.

Personal online configurable menus, toolbars and color palettes included in operator
settings.

Unique document concept for combining traditional process displays with web pages
and any ActiveX-based components as display documents.

Low bandwidth requirements.
Unique display sub-division and automatic run-time local cashing mechanism for fast
call up times, even over serial modem connections.

Support of all types of character Unicode’s.
Context-sensitive help, on-line help and tool tips.

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PROCESS COMMUNICATION UNIT

PCU400 is used for flexible and effective data acquisition in SCADA systems.

The PCU400 handles communication with RTUs, IEDs and Substation Automation System. It
provides flexibility, performance and scalability in a cost-effective manner. PCU400 supports a
number of different protocols. Each unit connects up to 64 asynchronous communication lines
at rates up to 64 Kbit/s.

PCU400 features:

Different protocols configured per communication channel
Bit-oriented protocols with OCC2-8 hardware
Cyclic scanning of RTUs and scan groups
Reduces SCADA server I/O overhead
Connected to servers via LAN/WAN (TCP/IP), dual LAN
Performs dead-band-based report-by-exception of data to the SCADA server
Data engineering with SCADA engineering tool or Excel-based tool

PCU400 is the modern product when implementing effective data acquistion with Network
Manager.

PCU400, Process Communication Unit 400 forms the communication interface to the network
of remote terminal units (RTUs) together with the Remote Communication Server, RCS,
located in the application server of a Network Manager SCADA system. The PCU400 can be
used as a SCADA front-end, communication gateway for Substation Automation systems or as
a standalone protocol converter. Two parts define the Data Acquisition system:

RCS Application, a software package running in the Application Server
PCU400, a front-end converter that implements the protocols and connects the physical
lines

PCU 400 can be used in a variety of configurations to cater for different network topologies
and different levels of fault tolerance in the system. The alternatives include single or
redundant PCU 400 units.
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GPS UNIT

SWITCH

PCU UNIT

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ADVANTAGES OF SCADA

After doing automation of grid basically we have increased the efficiency of electricity
distribution. There are some other methods which help in identifying the loss making zones
and overall improving the efficiency of distributions:

1. Automation of substation grid

2. Automated meter reading(AMR)

3. Geographical information system(GIS)

4. Energy audit and accounting

5. LT-ABC

6. High voltage distribution system(HVDS)

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