SCADA SYSTEM IN VISAKHAPATNAM STEEL

PLANT

A Project report submitted in partial

fulfillment of the requirements for the

award of

Bachelor of Technology

In

Electronics and communication

Engineering

Submitted by

K.DIVYA R.RAMYA

D.SHALINI CH.ANITHA BHAVANI

Under the Guidance of

B.KRUPANANDAM

Manager(Telecom)

Visakhapatnam Steel Plant

Visakhapatnam

VIGNANS INSTITUTE OF INFORMATIONTECHNOLOGY

(Affiliated to JNTU)

DUVVADA

CERTIFICATE

This is to certify that the Project work entitled “ SCADA system in VSP” is

a bonafide record of work done by K.DIVYA, R.RAMYA,

D.SHALINI,CH.ANITHA BHAVANI, students of VIGNAN’S INSTITUTE

OF INFORMATION TECHNOLOGY, DUVVADA VISAKHAPATNAM

have been sincere, dedicated and the conduct throughout the study has been

excellent in partial fulfillment of the requirement for the award of degree in

BACHELOR OF TECHNOLOGY under the guidance and supervision in

VISAKHAPATNAM STEEL PLANT.

Visakhapatnam Signature of Guide

Date :

ACKNOWLEDGEMENT

We hereby take this opportunity to express our sincere gratitude to the

following eminent personalities whose aid and advice helped us to complete

this project work successfully without any difficulty.

We are thankful to Mr. B.Krupanandam, Manager (Telecom) who has

been with us all through the project to spend his valuable time and to share

his knowledge.

As a token of our feeling, we would like to acknowledge our sincere

regards to our HOD Prof. A.SESHA RAO for allowing us to take up a

project in a working plant we express our gratitude to Dr.ARJUNA

RAO(Principal) VIIT for their cooperation during the project period. We

are also thankful to faculty members for their kind cooperation and

assistance.

INDEX

Abstract

Major Department of Visakhapatnam Steel Plant

Different Communication Systems in Visakhapatnam Steel

Plant

Introduction

Supervisory control and data acquisition system -

Architecture

Remote telemetry unit (RTU) – Block Diagrams

Modems

Cables

Master Station

Power supply requirements and specifications

Software

Conclusion

ABSTRACT

In this modern world of Industrialization and automation, energy

plays a major role in the growth of any organization. The utilization of

energy plays an impacting and direct role in the growth of organizations like

Visakhapatnam Steel Plant.

In Vizag Steel Plant, there is a supervisory control and data

acquisition system (SCADA) present for monitoring of energy networks

which are present through out the plant. The objective of this proposed

SCADA system is to monitor the energy usage and demands of various

consumers of the plant and exercise effective control over their energy

consumption optimum utilization of in-house energy resources.

In this modern world of competition, the technology is changing very

rapidly. To compete with the changes and to sustain the development,

Visakhapatnam Steel Plant is going for upgradation of its existing SCADA

system with the latest state of art – technology with the features like using

high speed processors having cache – memory and using the powerful

PLC’S(Programmable Logic Devices) controls.

This project makes a brief study of existing “SCADA” system present

in Visakhapatnam Steel Plant and the changes that are going to come to in

the proposed SCADA system that is to be installed in the near future.

GROWTH AND IMPORTANCE OF STEEL

INDUSTRY IN INDIA

Steel comprises one of the most important inputs in all sectors of economy. Steel

industry is both a basic core industry. The economy if any depends on strong base of iron

and steel industry in that nation. History has shown base of iron and steel industry in that

nation.

History has shown that countries having a string potentiality for iron and steel

production have played a prominent role in the advancement of civilization in the world.

Steel is such a versatile commodity that every object we see in our day to day life has

used steel either directly or indirectly.

However its use is innumerable to mention a few, it is used for such small items as

nails, pins, needles, etc., through surgical instruments, agricultural implements, ships,

boilers, frigates, railway materials, automobile parts etc., the great investment that has

gone in to the fundamental research in iron and steel technology has helped both directly

and indirectly many modern fields of today's civilization without steel. Steel is versatile

and indispensable item. The versatility of steel can be traced to mainly three reasons:

It is the only material item, which can be conveniently produced in tonnage

quantities.

It has got very good strength coupled with ductility and malleability.

Its property can be changed over a wide range.

It alloys easily with many of the common elements.

The properties can be manipulated to any extent by proper heat treatment

techniques.

Taking these factors in to consideration, it can be said without committing a

serious error, that the types of steel available are innumerable.

"VISAKHAPATNAM STEEL PLANT IS AN INTEGRATED

STEEL PLANT"

CHARACTERISTICS OF INTEGRATED STEEL PLANT:

This integrated steel plant has large capacities, highly capital intensive, labour

intensive and they would have all facilities including raw material resources, water

supply, power supply, testing and inspection facilities, township facilities, medical,

educational recreational etc., all under one administrative control. This would reduce

the extent of dependency on outside agencies, which would help the smooth running of

the plant.

TECHNOLOGY IN STEEL PLANT:

Visakhapatnam steel plant is the most sophisticated and modern integrated steel plant

in the country. Modern technology has been adapted in the many areas of production,

some of them for the first time in the country, among these are :

Selective crushing of coal.

Evenching of coke

Conveyor charging and bell less top for blast furnace.

100% continous casting of liquid steel.

Gas expansion turbine for power generation utilizing blast furnace top gas pressure.

Hot metal desulphurization.

Etensive treatment facilities for effluents for ensuring proper environment protection.

Computerization for process control.

Sophisticated, high speech and high production rolling mills.

HALL OF FAME:

Visakhapatnam steel plant has the distinction to be first integrated steel plant in

India to become a fully ISO9002 certified company. The certificate covers the quality

systems of all operational, maintenance, service units. Besides purchase systems,

training and marketing functions spreading over regional marketing offices,20 branch

offices and 22 stock yards located all over the country.

Visakhapatnam steel plant by successfully installing and operating efficiency

Rs.480 crores worth of pollution control and environment equipments and converting

barrel landscape by planting more than three million plants has made the steel plant

township and surroundings in to heaven of greenery.

Visakhapatnam steel plant exports quality pig iron and steel products to Srilanka,

Myanmar,Nepal, Middle East ,USA and South East areas.RINL- Visakhapatnam steel

plant was awarded "STAR TRADING HOUSE" status during 1997-2000. Having

establishing a fairly dependable export market.

Having a total man power of 17250 Visakhapatnam steel plant has envisaged a

labour productivity not less than 230 tonnes of liquid steel per man, which is the best in

the country and is comparable with the international levels.

MAJOR DEPARTMENTS OF

VISAKHAPATNAM STEEL PLANT

RAW MATERIAL HANDLING PLANT(RMHP):

The RMHP receives the basic materials required for the steel making process from

various sources through wagons which are stacked and reclaimed by stackerd and

reclaimed by stackers-cum reclaimers and distributed to various departments of

Visakhapatnam steel plant through conveyor systems.

COKE OVENS (CO):

Coke is a hard, porous mass obtained by fractional distillation of coal in the absence

of air at a temperature above 200deg.centigrade for period of 16 hrs to 18 hrs. It is used

as a fuel and reducing agent of iron ore in blast furnace. Three coke oven batteries for

production of 2.26 MT dry coke, each with 7 meters tall 67 ovens. Each battery is

provided with facilities for dry cooling of coke using nitrogen as quenching media for dry

cooling of coke as well as for recovering sensible heat of coke. As a by-product a CO

gas is produced in this processes and this gas is having a very high calorific value for

about 2400-2700KCAl and is produced throughout the plant as a fuel.

SINTER PLANT:

Sintering is one of the most widely used and economic agglomeration techniques.

Sinter is a hard and porous lump obtained by agglomeration of fines of iron ore, coke,

limestone , and metallurgical waste. Sinter increases the productivity of blast furnace,

improves the quality of pig iron and decreases the consumption of coke rate. Two 312

square meter sinter machines with 420 square meter straight stand type coolers for annual

production of 5.26 MT sinter.

BLAST FURNACE(BF):

Pig iron or hot metal is produced in the Blast Furnace. The furnace is named as

BF as it is run with blast at high temperature and pressure of 1500 deg. C. Raw materials

required for pig iron and iron are iron making ore, sinter, coke, and lime stone. There are

two 3200 cubic meter blast furnace to meet 3.0 MT annual metal requirement. Each

furnace is designed for 205 at mg top pressure, and will be belt charged and equipped

with bell-less Paul-wurth top. Each furnace is provided with a set of four hot blast

furnace stoves designed for supplying air blast up to 1300 deg.C. Three turbo

blowers ,one for each furnace and one stand by common to both furnaces are provided

with 12 MW top pressure recovery turbo generating power. BF gas is produced from

each furnace is being cleaned in gas cleaning plant comprising dust catcher, high pressure

scrubber and is distributed through out the plant as a fuel.

STEEL MELT SHOP(SMS):

Steel is an alloy iron and carbon ,where carbon should be less than 2%.Hot metal

produced in B.F contains impurities like carbon, sulphur, phosphorous, silicon etc., these

impurities will be removed in steel making by oxidation process. These are the three L.D

convertors to convert hot metal in to steel. The steel melt shop complex comprising two

1300-ton hot metal mixers, three 130-ton LD converters (two operating) and six 4-stand

bloom casters. Each converter is being provided with gas cleaning plant for cleaning and

recovery of LD gas, which will be used as fuel in plant.

ROLLING MILLS(RM):

Blooms cannot be used as they are in daily like. These blooms have to be reduced

in size and properly shaped to fit for various jobs. Rolling is one of the mechanical

processes to reduce large size sections in to smaller ones. The cast blooms from CCM

are heated and rolled in to long products of different specifications like high capacity,

sophisticated high-speed rolling mills. The rolling mill complex comprises :

Light and medium merchant mill (LMMM)

Wire rod mill (WRM)

Medium merchant and structured mill (MMSM).

Each mill is well equipped with required number of walking beam furnaces for

heating of walking beam furnaces for heating of blooms or billets and except for wire rod

mills, each furnace is provided with evaporative cooling system for generation of steel for

plant consumption.

THERMAL POWER PLANT(TPP):

The estimated power requirement for V.S.P in 280 at 3.0 MT stages, the peak

load being 292 MW essential loads being 49 MW. The generating capacities 286.5

MW. A captive power having 3*60 MW turbo-generator sets and 5*330 ton/hr steam

generators. In this plant, 6000 Nm^3/min turbo blowers are being provided for supplying

cold air blast furnaces.

TYPES OF COMMUNICATION EQUIPMENT AVAILABLE

In this modern age of industrialization telecommunications plays a very important

role in coordinating the activities of various departments / sections and in achieving the

set targets and also in improving the performance of any organization. In Visakhapatnam

Steel Plant, different types of communication systems are being used to meet the internal

and external communication needs. These are broadly classified as follow:

a. General purpose communication systems.

b. Process communication systems.

c. Monitoring & Signaling Systems.

GENERAL PURPOSE COMMUNICATION SYSTEMS :

The following facilities are provided under category of general purpose communication

systems:

3000 lines Electronic Exchange in Plant.

2000 lines Electronic Exchange in Township.

100 lines Electronic Exchange in Visakha Steel General Hospital.

44 lines Electronic exchange in Hill Top Guest House.

2500 Lines Electronic Exchange of Bharat Sanchar Nigam ltd (BSNL) in Project

Office is catering to the needs of Plant area and Sectors-I to VII in township.

Another 2000 Lines Electronic Exchange of Bharat Sanchar Nigam ltd (BSNL) in

Township is catering to the needs of Sectors-VIII to XI in Township.

The 3000 Lines electronic exchange in plant and 2000 lines exchange in township

are having the following facilities:

Extension (subscriber) to extension call, Auto call back, Hot lines, Music on hold,

Reminder Alarm, Automatic line testing facility, Faults man ring back, Call consult

facility, Malicious call tracing facility, 3 party conference Facility and Howler Tone alert

etc.

All exchanges working in the steel plant are interconnected by means of junction

lines and have closed numbering scheme. For communicating with any subscriber of any

exchange no extra digits have to be dialed and only the desired number is to be dialed. –

connection pattern given at fig 1.

The 2000 lines exchange in township is interconnected to the BSNL network. Due

to this interconnection all the subscribers of this exchange can receive incoming calls

from any part of the world. A few subscribers are provided with facility to contact

subscribers connected to the BSNL network and cellular and mobile phones in and

around Visakhapatnam.

PROCESS COMMUNICATION SYSTEMS :

To facilitate coordination, operation & management activities of production,

maintenance & service departments, the following process communication systems are

provided:

a) Despatcher communication system

b) Loudspeaker intercom systems

c) Loudspeaker broadcasting systems

d) Loudspeaker conference communication system

e) Industrial public address system

f) Hotline communication systems

g) VHF communication systems

A) DESPATCHER COMMUNICATION SYSTEMS:

Initially cordless switch board type manual exchanges of electromechanical

version were provided. Since manufacture of such systems and their spares is

discontinued in the country, these despatcher systems are being replaced by Electronic

exchanges progressively. Except the ones in CCCP other systems have been replaced.

These would also be replaced very soon.

Production coordination at plant level being conducted by ED (Works) with all

HODs in the morning every day is facilitated with the help of the digital EXCOM system

provided in the plant control room.

B) LOUDSPEAKER INTERCOM SYSTEMS:

Loudspeaker intercom systems are working LMMM & WRM. These systems are

used for communication between various sections of the same production shop.

Communication is made possible using microphones and loudspeakers provided in the

subscriber stations. This system is very useful in noisy environment where conventional

telephones are ineffective. This system helps to establish communication between any

two stations having interconnectivity on selection basis. By using group call facility it is

possible to communicate to all the subscribers in the group at a time.

c) LOUDSPEAKER BROADCASTING SYSTEMS:

Loudspeaker broad casting systems are provided in C&CCD, BF, SP and SMS

departments. This system is useful to make general announcements to the entire area of

working and so can be used to locate operation / maintenance personnel working on the

shop-floor so as to pass-on important instructions from the control room.

D) LOUDSPEAKER CONFERENCE COMMUNICATION SYSTEMS:

Loudspeaker conference communication systems is working in CCCP. These

systems are provided with both paging and private channel communication facilities. In

case of paging a general announcement can be made which is heard on all the stations. In

the private mode communication is possible between two selected stations only. Here

also communication is carried out by means of microphones and loudspeakers provided

in the subscriber stations.

E) INDUSTRIAL PUBLIC ADDRESS SYSTEM:

Industrial Public Address System is working in TPP. It is a combination of

loudspeaker broadcasting system and conference communication system. From the main

control room it is possible to make announcements which are heard on the shop-floor.

From certain locations the communication can also be established through handsets in

private mode with the main control room.

F) HOTLINE COMMUNICATION SYSTEMS:

To ensure direct telephone communication between closely related critical

locations hot lines are provided. By using the hot lines specified locations are connected

permanently. Communication is possible only between these two locations. When one

subscriber lifts his telephone the other will immediately get a ring and communication

can be had without any loss of time. This is useful to pass-on urgent messages. These hot

lines are initially provided with direct line communication systems which are electro

mechanical systems. Due to obsolescence electronic systems are now being used for most

of the locations. Hot lines are working in CCCP, BF,SMS, LMMM, WRM, MMSM,

TPP, PPM, DNW and WMD departments.

G) VHF COMMUNICATION SYSTEMS:

VHF communication systems are used in our plant to establish two way

communication between two or more when either or one of them is moving. There are

three models working in our plant. They are hand-held units (walkie-talkie), vehicle

mounted – mobile units and base station units. Walkie-talkies are used by operation and

service personnel in almost all of the production shops. Vehicle mounted units are being

used by DNW, CISF (Fire) and CISF (security). Base station units are used by CISF

(fire), CISF (Security), Administration, DNW and largely by CCCP departments. In

CCCP these can be seen in pusher cars, charging cars, door extractors, electric locos,

lifters and CDCP area.

MONITORING AND SIGNALING SYSTEMS :

To facilitate monitoring production, maintenance & service activities, the following

monitoring and signaling systems are provided:

a) Closed Circuit Television Systems (CCTV):

b) Central fire alarm signaling system

c) SCADA system

d) Shift change Announcement Siren System

A) CLOSED CIRCUIT TELEVISION SYSTEMS (CCTV):

For monitoring critical operations in different production units continuously from the

concerned control rooms / pulpits CCTV systems are used in SP, BF, SMS, LMMM,

WRM and MMSM departments. CCTV system comprises of CCTV camera with a lens

and a CCTV monitor. In some cases a video switcher, a central control console, pan and

tilt head and zoom lens are also used. These are interconnected by means of control

cables and / or coaxial cables Necessary protection is provided for the CCTV equipment

depending on the locations where they are used

B) CENTRAL FIRE ALARM SIGNALING SYSTEM:

The central fire alarm system is provided for communicating the exact location of

outbreak of fire in any part of the steel plant complex to the central fire station and

simultaneous actuation of sirens to alert personnel of the affected plant zone. The system

employs manual call points located all over the plant.

c) SCADA SYSTEM :

To monitor the consumption of energy by various users in the plant SCADA system is

provided. This is placed at Energy and Telecom centre. The system comprises of a master

station equipment with supervisory consoles and mimic panels located in the Energy &

Telecom Building, 23 Nos Remote Telemetry Units (RTUs) installed in different plant

units and 3 local RTUs for driving the mimic panel in the Energy centre. The RTUs will

be collecting the signals from the local instrumentation & electrical systems and

transmitting to the master station by means of RTUs. The RTUs are connected to the

master station by under ground telephone cables.

D) SHIFT CHANGE ANNOUNCEMENT SIREN SYSTEM:

The shift change announcement siren system is provided for ensuring uniform and

accurate shift timings throughout the plant. This system consists of two(2) nos quartz

crystal controlled master clocks in the Energy & Telecom Centre. The shift timings are

programmed in the Master Clock. At the specified time, the signal will be transmitted for

energizing the sirens located at strategic points in plant area simultaneously at the preset

timings.

Apart from the above facilities Telecom department maintains the following cable

networks also

a) DATACOM cable network in plant

b) Telephone cable network in plant and township

INTRODUCTION

Acronym for supervisory control and data acquisition, a computer system for

gathering and analyzing real time data. SCADA systems are used to monitor and control

a plant or equipment in industries such as telecommunications, water and waste control,

energy, oil and gas refining and transportation. A SCADA system gathers information,

such as where a leak on a pipeline has occurred, transfers the information back to a

central site, alerting the home station that the leak has occurred, carrying out necessary

analysis and control, such as determining if the leak is critical, and displaying the

information in a logical and organized fashion. SCADA systems can be relatively simple,

such as one that monitors environmental conditions of a small office building, or

incredibly complex, such as a system that monitors all the activity in a nuclear power

plant or the activity of a municipal water system. SCADA systems were first used in the

1960s.

CENTRAL SUPERVISORY CONTROL AND DATA ACQUISITION

SYSTEMS :

The system comprises of Micro VAX ll based Master station equipment with

supervisory consoles and mimic panels located in the energy and telecom building

and 23 RTUs installed in different plant units and 3 local RTUs for driving the mimic

panel in the energy centre . The RTUs will be connecting in the signals from the

instrumentation and electrical systems and transmitting to the Master station when

polled by the latter. The RTUs are connected to the master station by under ground

telephone cables . Supervisory consoles are also provided in MRS & EMD

departments in area shop office of utilities .

The system enables continuous monitoring of the energy networks in the steel

plant and generation of reports as required for taking strategic decisions in times of

crisis . The maintenance of RTUs mimic panel and the cable network between the

field / local RTUs & modem panel in the Master station is carried out by the telecom

department .

The signals for a plant unit will normally be concentrated in the control room

of the unit from where the unit is being operated . RTUs of the CSCS will be in

stalled in these main control rooms and the tele -- transmission signals identified for

the units will be wired to the RTUs . The RTU are called as Remote terminal /

telemetry units.

The RTUs are micro processor based intelligent units , responsible for

Acquisition of inputs from the plant units and convert them in to digital code for Tele

-- transmission to the Master station computer of CSCS through the 5 pair telephone

cable . Some plant unit where few signals are available for tele – transmission , A

junction box will be installed in the control room ( instead of an RTUs) for the

termination of inputs and these inputs are further connected to the nearest RTUs

through the multi – core control cables.

The system consists of computer based Master station with dual hot Stand

by computers . The peripherals like terminals , printers , communication Ports etc…

which are common requirements for the computer system are Connected through a

peripheral transfer switch ( PTS ) to the computers . The 23 RTU s are located in

different parts of the plant are connected to the center Master station through modems

in a multi dropped fusion to different channels Of communication controller . The

Master station located in the Central Dispatcher station ( C D S ) of the

Visakhapatnam steel plant will acquire all Information through RTU and

communication controller module ( CCM ) and Process the information for displays

and report generation .

The SCADA system shall acquire various electrical & utility parameters for

effective monitoring & control operation . The various parameters acquired shall be

such as electric power , voltages , currents , etc… under electrical monitoring and

parameters such as flows , temperatures, pressures , etc … for operation and

functional convenience the system categorized in to 2 following systems.

Utility systems

Electrical systems

UTILITY SYSTEMS :

The utility system covers the services like fuel , gases , stream , comprised

air, water etc…. The services covered by the utility systems of CSCS are

broadly classified in to following groups.

Fuel gases system : CO, BF ,Mixed & converter gases.

Process gas system : Nitrogen, Oxygen ,Argon, Acetylene.

Stream Distribution system: Stream at 40 KSCG,13 KSCG.

Compressed air system: Compressed air and instrumentation grade air

Chilled water system: Chilled water.

Fuel oil system : LSHS,LDO and LTF.

Water systens: make up water, fire and drinking water.

ELECTRICALSYSTEM

The electrical system covers the complete electrical distribution network

Inside the Visakhapatnam steel plant like 220 KV ,11 KV, 6.6 KV systems in

MRS, LBSS , 1, 2 , 3 , 4 and 5 , LBDSS , HVLCS and HUMCCS.

For centralized supervisory of above services in utility and electrical systems and

also to exercise control over their optimum utilization, following types of signals are

considered for the uses .

Analog input (AI)

Digital input (DI)

Analog output(AO)

Digital output (DO)

Pulse input (PI)

The input signals acquired by the RTUs are tele-transmitted to the Master station

and are sorted out according to the above subsystem division i.e. utility and electrical.

The MS is provided with separate operator stations for utility &electrical system for

independent operations.

SCADA systems monitors a total no 5000 different signals originating at

different dept in VSP. Among these 5000 signals 1500 signals are catered to monitor

utility system and 3500 signals are electrical system.

The CSCS MS hard ware comprising of Micro computer, Peripheral devices

like operator stations, printers & power supply unit like U P S , batteries, distribution

board will be housed in the second floor of the CDS building where separate rooms with

A.C facilities are provide in VSP. False flooring is provided for inter connection cables.

Full graphic type of mosaic wall boards one for utility system and another for

electrical system displaying the distribution network of various services and power flow

inside the VSP envisaged. The wall boards are located in the main control room of the

supervisory center where the operator console of the CSCS is located.

There are interconnecting cables between

# RTU and the MS.

# Junction box and the RTU.

# Remote video terminals and MS.

Modems are provided for both the ends of communication link for inter

connection of Remotely placed units to the MS. These are placed to make up the cost

potential in the line .

Software in the Ms is also required to meet all the functional requirements such

as data acquisition, display, reporting ,trending ,performing application programs etc…

The maintenance of RTUs mimic panel and cable network between the field / local

RTUs and the modem panel in the MS is carried out by the telecom dept.

REMOTE TELEMETRY UNIT (RTU)

The micro processor based RTU s are installed at various plant Units.

The RTUs will be collecting the signals from the local Instrumentation &

Electrical systems and transmit to the MS when they are polled by the latter.

The RTUs are connected to the MS by under ground telephone

cables with ac MODEMS at MS end and dc MODEMS at RTU end.

OUTSTATION RTU HARDWARE:

The RTU H/W has the following contents:

(1) RTU cabinet

(2) Gland plates / field cables

(3) Terminations and interposing relays

(4) Basic Tier

(5) I/O Tier

(6) Power Supply Arrangements

(7) Basic Modules

(8) I/O Modules

(9) RTU I/O configuration

RTU CABINET :

The RTUs are houses in standard fabricated steel cabinets of Rugged

construction.

The RTU cabinet has an internal structure for:

# Routing the field cable to the terminations.

# Mounting the terminations and interposing relays.

# Routing the I/O cables from the termination and

interposing relays to the electronic tires.

# Mounting the electronics comprising PCCs fitted in tires.

# Mounting the Power supply unit for providing the logic supplies

to all cards.

The general layout of the RTU cabinet is attached.

A signal cabinet can accommodate a basic tier and an I/O tier. If

further expansion requires two I/O tiers can be added.

GLAND PLATES / FIELD CABLES :

All external connections to the RTU enter the cabinet through Gland plates.

The external connections are communications connection, Power connection and

mainly the field cable connecting to the plant Instrumentation.

TERMINATION & INTERPOSING RELAYS :

The field cables entering the RTU are terminated on screwed

Terminals mounted on vertical rails. The interposing relays are plug in type and are

accommodated in power supply cabinet installed adjacent to RTU cabinet.

The interposing relays are provided where the output control Logic power is

not sufficient to operate a high voltage and current Points.

The connections are made by standard multicore twisted pair Cables

and gold ribbon connectors.

Dia : Testing of in coming signals to RTU from field.

BASIC TIER :

The basic tier is fitted at the top of the cabinet . It houses

1. The basic cards comprising microprocessor card (MP 3) the Analog/Digital

converter (ADC 4) and the master control / test Cards (MCT 2).

2. Upto 8 input / output cards.

3. Power supply Adapter card to distribute the supplies to PCBs.

INPUT / OUTPUT TIER :

The input / output tier is fitted below the basic tier and can

Accommodate upto 19 input / output cards.

POWER SUPPLY ARRANGEMENTS :

All RTUs are provided with 230 KV AC operation. The RTU Power

supply unit operates on 24 V DC input and generates all logic Supplies +5V, +12V

and -12V required for the oprations of the RTU. The input 24 V DC is derived

from local mains power supply with a Battery back –up provisiopn with

maintenance free sealed lead acid batteries for 8 hours.

BASIC MODULES :

a) Micro Processor Module (MP 3) :-

The MP 3 is a signal printed circuit board designed for general Use in

telecontrol systems to provide intelligence at the out station, Master station front

end to the main computers telecontrol test Equipment and standby system

operation.

# The units is based on 8 bit Motarola M6800 micropocessor.

# The module incorporates a maximum of 8K bytes of PROM

and 4 K bytes RAM.

# The data acquisition, data processing, communication and

housekeeping information of the RTU are performed using

this module with memory.

# This card provides I /O bus catering to the I /O modules end

serial communication interface to modem for communication.

The logic requires the following supplies for a fully fitted card +5

at 2A, +12V at 0.3A and -12V at 0.15A.

# Facility has been provided for memory extension.

b) Master control test card ( MCT 2 ) :

# This module provides the number of RTU house keeping and

security checking functions.

# This card is degigned to fit a standard I / O card position.

# Main functions :

# Supply of powre to state control relays with local isolation

racllities.

# Generation of check logic pattern on a spection monitor

adderss.

# Generation of ADC calibration check reference voltage .

LEDs are provided to indicate controls.

Internal power required +12V at 28mA

+12V (HU) at 1mA

+15V (ISOL) at 1mA

External power required 24 V or 48 V.

c) Analog to digital conversion card ( ADC 4 ) :

This card provides successive approximation A / D converter which

Converts 1- 5 volts full scale into 11 bits plus sign digital value.

# This card is used to convert analog input signals into digital

binary data (2’s complement or unipolar or offset binary )

# Opto Isolater s -> to form a barrier between the floating

analog conversion side and an 8 bit moniter high way.

# Analog input are superimposed on common mode. Voltages

to be digitized. Maximum voltage is 50 V dc & value is –80 bd.

# A start conversion signal starts the ADS digitizing cycle and

resets the clock control at the end of conversion.

# When the cycle is complete, the digital data is transferred to

shift register and clocked out across the isolation barrier to a

second shift register. Then data transfer complete signal resets

the clock control and also generates an ADC interrupt / Resets

to indicate data is ready to transfer.

# The basic conversion time is 300ms.

# An ADC output enable signal enables the two- byte transfer

of digitized data on to the moniter highway .

First byte consists of 8 MSB bits includes sign bit ( if bipolar )

Second byte contains the 4 LSB bits.

I / O MODULES :

I/O module unit comprises of the following five I/O cards.

1. ANALOG INPUT MODULE (AMFS 3) :

The AMFS cardscales and filter 8 high level analog current or Voltage

input which are multipexed by relays on to a common output circuit .

# It accepts voltage or current input presented by the instrumentaion.

# The card multiplxexes 8 input to the ADC

# The card accepts either 4—20 m Amps or 1—5 Volts Signals .

# The card function address ( lower ) is set by switches or liens on

the card

# For an 8 bit A/D conversion 1 function adderss is required .

For more than 8 bit conversion 2 function adderss is required .

# In cases of Ms. 8 bits of each of 4 digitized values are allocated

byte position 0,2,4 and 6. The remainder of each value is placed

in the adjacent add byte.

# The card operates from a + 12 V source at 1mA .

( for CMOS Logic )

(2). STATE MONITER BARRIER ( SMB 11 ) :

The SMB 11 card provides an electrically isolated interface between 32

signal bit plant status inputs and an 8 bit monitor high way . Plant input is

typically a dry contract switching 24 volts ( negative ) to a filter , limiter and opto

isolators which gives 1500 volts plant to logic isolaction . The filter time constant

is nominally set to 10 mA . The current for each input is 5 mA and the 32 inputs

have a common positive return.

(3). STATE CONTROL BARRIER ( SCB 8 ) :

The SCB 8 provides 8 signal bite stae control output an 8 bit control

Highway . Electrical isolation is provided by the use of opto-isolators- ( 1500

volt isolated ) which provide an output of 100 mA at 24 V DC . An ‘on’ output

sinks into a common negative rail .

(4). TOTALISER CARD ( TL 3 ) :

The TL 3 card count 4 independent pulse stream , in to 8 digit BCD

counters . Each total , 32 bits , can be read by the appropriate function address on

to the moniter highway in 4 byte each of 8 bits .

PRINCIPLES OF SYSTEM OPERATION :

The basic principle of this system of data transmission between the Master

Station ( MS ) and any particular RTU in either direction is time – division

multiplexing .

Where the MS has to communicate with a number of RTU’s

multidropped on a common communication circuit . this system normally uses

time — division multiplexing between RTU’s .This is achieved by use of the uniqe

outstation address encoded in the hardware of each RTU.

The basic of data transmission is the word . In interrogation mode the word

comprises two message , the interrogation message directed from MS to RTU s .

INTERROGATION MODE WORD STRUCTURE:

Address byte: out station address.This is the unique address of the RTU being

interrogated.

Byte count Byte: this is the number of information bytes in the message.

Information bytes: function address and data bytes.These bytes may be used to transmit

information to the RTU, or to define which information to the RTU is to transmit back to

the MS.

MODEMS

The multi-tech computers multi 748 A is a microprocessor controlled CCIT V.27

bits/tier compatable leased line modem. It can be operated at 2400 or 4800 baud, in either

two or four wire synchronous modes. Two-wire operation is only half duplex. The multi

modem 748 A incorporates fall back to 2400 baud when operating the V.27 internal DIP

switches, jumpers and modem commands control the mode of operation.

MASTER STATION

OBJECTIVE:

The Master Station located in the CDS building in VSP will acquire all

information through RTUs and CCMS and process the information for displays and

report generations which are very important at the times of crisis to take strategic

decisions.

The master station hardware comprises of the following:

Host computer Micro VAX II

Communication concentrator module(CCM)

S/3 intelligent colour console

Peripheral transfer switch (PTS)

DELNI

System Console

Magnetic tape subsystem

Hard disk subsystem

VT-320

Digitizer pad

Communication transfer switch

Common controller interface module

HOST COMPUTER:

The host computer is the main controlling element of the S/3 SCADA system. The

host contains the S/3 application S/W and is responsible for the bulk data storage

functions . The typical host consists of a computer unit ,tape and/or disk drives and alarm

types. The host computer is one of the Digital Equipment Corporations (DEC) VAX

family of general -purpose computers .

CONCLUSIONSupervisory control and data acquisition system is a versatile network of

intelligent sub systems, which has brought revolution in the field of monitoring and

controlling systems. Earlier due to lack of sophisticated equipment it was very difficult

to predict whether the channel corrupted the data coming to the monitoring station or it is

the date pertaining to a functional error in a particular department. Further it was a very

time consuming process to undo the effect causing the problem (only after making sure

the data received is correct). In the mean time a lot of energy is waste and sometimes

even unacceptable hazards also used to take place. Also there was no privilege to track

the position that is responsible for the error.

The supervisory control and data acquisition system over comes all the above

bottlenecks. It has host computer in the master station to store the data for a long period

of time so that it can be sued to take strategic decisions sat the time of crisis.

The proposed SCADA System for Vizag Steel Plant shall acquire various

electrical and utility parameters for effective monitoring and control operations. The

various parameters acquired shall be such as electric power, voltages, currents, etc.

under electrical monitoring and parameters such as flows, temperatures pressures, etc.

under utility monitoring.

These parameters are logged into the system using a suitable database

management system. The data is processed and presented in the plant to the concerned

officials and operators using user-friendly graphical interfaces.