TYPICAL SCADA SYSTEMTYPICAL SCADA SYSTEM

SCADAH/W &

S/W

MEDIA

C TXO RX M EM QN P T

C TXO RxM EM QN P T

R

T

U

T PR AA NN ES LDUCER

C & R

PANEL

CONTROLCENTRE SUBSTATION / GEN STATION

COMMNMEDIA

FIELD UNIT

Instrumentation For SCADAInstrumentation For SCADA

TransducersTransducers RTURTU Current TransformerCurrent Transformer Capacitor Voltage TransformerCapacitor Voltage Transformer

TRANSDUCERTRANSDUCER

Device converts one form of energy to another form.Device converts one form of energy to another form. Energy form viz. electrical, mechanical, chemical etc.Energy form viz. electrical, mechanical, chemical etc. Transforms High level to Low levelTransforms High level to Low level Input – Hundreds of voltInput – Hundreds of volt Output – Few milliamperesOutput – Few milliamperes Measures field parameters like voltage, frequency, Measures field parameters like voltage, frequency,

current, 3 phase bi directional active & reactive power current, 3 phase bi directional active & reactive power and transformer tap positionand transformer tap position

Accuracy : +/- 0.2% class for frequency transducers Accuracy : +/- 0.2% class for frequency transducers and +/- 0.5% class for other transducersand +/- 0.5% class for other transducers

TRANSDUCERTRANSDUCER TYPICAL RATINGTYPICAL RATING TransducerTransducer Input Input OutputOutput Voltage 0-110 V 0-10 mAVoltage 0-110 V 0-10 mA Current 0-1 Amp 0-10 mACurrent 0-1 Amp 0-10 mA 0-5 Amp0-5 Amp Frequency 4-20 mAFrequency 4-20 mA MW 4-12-20mAMW 4-12-20mA MVAR 4-12-20mAMVAR 4-12-20mA

RRemote emote TTerminal erminal UUnitnit

The RTU performs the data acquisition and The RTU performs the data acquisition and supervisory control over the substation for the SCADA supervisory control over the substation for the SCADA system.system.

As a minimum, the RTU collects, processes and As a minimum, the RTU collects, processes and transmits the data from the substation to the control-transmits the data from the substation to the control-centers.centers.

The following data are generally acquired from the The following data are generally acquired from the sub-station:-sub-station:-

AnalogAnalog- Power, Reactive Power, Voltage, - Power, Reactive Power, Voltage, Frequency, Current.Frequency, Current.

DigitaDigitall- Circuit Breaker Status, Isolator Status,SOEs- Circuit Breaker Status, Isolator Status,SOEs The RTU also receives and processes digital and The RTU also receives and processes digital and

analog commands. analog commands.

RTU: MAIN FUNCTIONSRTU: MAIN FUNCTIONS

SCADASCADA Local ControlLocal Control Data LoggingData Logging Process ControlProcess Control

HARDWARE CONNECTIVITY DIAGRAM FOR SCADA HARDWARE CONNECTIVITY DIAGRAM FOR SCADA AT SUBSTATION / GEN.STATIONAT SUBSTATION / GEN.STATION

MAINCPU

BOARDPSU

COMMNBOARD

ANALOG

I / P

DIGTAL

I / P

CONTROLO/P

TERMINALBLOCK

TERMINAL BLOCK

TERMINALBLOCK

REMOTE TERMINAL UNIT

TRANSDUCER O/P TERMINAL

MVAR VOLTMW

TRANSDUCER I/P TERMINAL P TSEC

110VAC

CT SEC1 AMPS

FROM

SWITCHYARD-FIELD

EVENT LOGGERPANEL

DRIVER

RELAY

TRANSDUCER PANEL

RS232 PORT

SCADA HARDWARE CONNECTIVITY WITH SCADA HARDWARE CONNECTIVITY WITH COMMUNICATION SYSTEM(PLCC) AT SUB-STN/GEN STCOMMUNICATION SYSTEM(PLCC) AT SUB-STN/GEN ST

RTU

NSK5

modem

PLCC T x / R xSPEECH / DATA

PANEL

RS 232 CONNECTIVITY

PLCCINDOOR EQUIMENT

TRANSDUCERSTRANSDUCERS

CLASSIFICATIONCLASSIFICATION SELF POWERED/AUXILARY POWEREDSELF POWERED/AUXILARY POWERED

INPUTINPUT VOLTAGE/CURRENT/POWER/POSITIONVOLTAGE/CURRENT/POWER/POSITION

OUTPUTOUTPUT 0-10mA, 4-20mA, 0-5mA 0-5v,0-10v0-10mA, 4-20mA, 0-5mA 0-5v,0-10v

OUTPUT IMPEDANCEOUTPUT IMPEDANCE 500500ΩΩ,1000,1000ΩΩ,2000,2000ΩΩ

ACCURACYACCURACY 0.2 CLASS, 0.5 CLASS, CLASS 2 AND ABOVE0.2 CLASS, 0.5 CLASS, CLASS 2 AND ABOVE

A/D CONVERSION AT RTU LEVELA/D CONVERSION AT RTU LEVEL(16 BIT ADC).(16 BIT ADC).

FOR MW / MVAR TRANSDUCER:INPUT: PT SEC PHASE TO PHASE : 110VAC CT SEC TWO PHASE CURRENT (R & B): 1 AMPS.

OUTPUT : 4 – 20mA(TRANSDUCER OUTPUT)

IN ADC:

AT 4mA = 6553 CountAT 20mA = 32767 Count12mA IS THE CENTRE POINT.(+/- 0.1% IS THE ACCEPTABLE RANGE OF ERROR ON FULL SCALE)( Ref Calculation Sheet for all type of Measurand)

TRANSDUCERSTRANSDUCERS Measures field parameters like voltage, frequency, Measures field parameters like voltage, frequency,

current, 3 phase bi directional active & reactive current, 3 phase bi directional active & reactive power and transformer tap position.power and transformer tap position.

RatingRating Vol: 110/115 volts phase to phaseVol: 110/115 volts phase to phase

Current : 1 ACurrent : 1 AFrequency: 45-55 HzFrequency: 45-55 Hz

Output : 4 – 20 ma / 500 ohmsOutput : 4 – 20 ma / 500 ohms External power supplyExternal power supply IEC 688IEC 688 Accuracy : +/- 0.2% class for frequency transducers Accuracy : +/- 0.2% class for frequency transducers

and +/- 0.5% class for other transducersand +/- 0.5% class for other transducers

SALIENT FEATURES OF ULDC RTUSALIENT FEATURES OF ULDC RTU A small rugged computerA small rugged computer CPU, volatile & non-volatile memory, power CPU, volatile & non-volatile memory, power

supply module, I/O modulesupply module, I/O module Communication ports & maintenance portsCommunication ports & maintenance ports Allows the central SCADA master to communicate Allows the central SCADA master to communicate

with the field deviceswith the field devices Acquires the data from the field Acquires the data from the field

devices/equipment and transfers the data to the devices/equipment and transfers the data to the SCADA systemSCADA system

Distributed Processing Technology Distributed Processing Technology Main processor is 32-Bit 16Mhz and sub modules Main processor is 32-Bit 16Mhz and sub modules

are 8-bit.are 8-bit. Real time clockReal time clock Access via PC-Based Configuration.Access via PC-Based Configuration. Password Protected.Password Protected. Database configured via a PC and can be Database configured via a PC and can be

downloadeddownloaded

SALIENT FEATURES OF ULDC RTUSALIENT FEATURES OF ULDC RTU Switch mode converter power supply module which Switch mode converter power supply module which

provides power for mother board, VME cards, I/O provides power for mother board, VME cards, I/O modules and peripherals. Input voltage – 241 V AC, modules and peripherals. Input voltage – 241 V AC, 50 Hz. Outpit voltage +/-5V DC, +/- 12 V DC, +/- 24 50 Hz. Outpit voltage +/-5V DC, +/- 12 V DC, +/- 24 V DCV DC

32 Analog inputs per module ,15 bit resolution .32 Analog inputs per module ,15 bit resolution . Conversion rate 660 ns for all 32 inputs.Conversion rate 660 ns for all 32 inputs. 64 status inputs per status module,1ms scan time 64 status inputs per status module,1ms scan time

for 64 inputs,1ms SOE resolution. A simple status for 64 inputs,1ms SOE resolution. A simple status input/SOE input/accumulator input can be input/SOE input/accumulator input can be connected. LED indicators for each input. Contact connected. LED indicators for each input. Contact wetting voltage supplied by power supply module.wetting voltage supplied by power supply module.

32 control output per control module. Two master 32 control output per control module. Two master relays for each output. One for close and one for trip.relays for each output. One for close and one for trip.

Through the maintenance port, we can download the Through the maintenance port, we can download the database, view data and Communications specific to database, view data and Communications specific to each peripheral board and trouble shoot . each peripheral board and trouble shoot .

Advanced diagnostic capabilitiesAdvanced diagnostic capabilities Time synchronisation of RTU done at every 1 minute.Time synchronisation of RTU done at every 1 minute.

Scan CyclesScan Cycles All the analog data are scanned every All the analog data are scanned every

10/12 seconds10/12 seconds Status information are reported by Status information are reported by

exceptionexception All status information are scanned for All status information are scanned for

integrity check every 10 minutesintegrity check every 10 minutes The SOE datas are time stamped at 1 ms The SOE datas are time stamped at 1 ms

resolution resolution Time synchronisation is done every 10 Time synchronisation is done every 10

minutesminutes

Current TransformerCurrent Transformer

A current transformer is a measurement A current transformer is a measurement device designed to provide a current in device designed to provide a current in its secondary coil proportional to the its secondary coil proportional to the current flowing in its primary .current flowing in its primary .

The current transformer isolates The current transformer isolates measurement and control circuitry from measurement and control circuitry from the high voltages typically present on the high voltages typically present on the circuit being measured .the circuit being measured .

Common secondary are 1 or 5 amperes. Common secondary are 1 or 5 amperes. For example, a 4000:5 CT would provide For example, a 4000:5 CT would provide an output current of 5 amperes when an output current of 5 amperes when the primary was passing 4000 amperes .the primary was passing 4000 amperes .

Capacitor Voltage Capacitor Voltage TransformerTransformer

Capacitor Voltage transformers (CVTs) Capacitor Voltage transformers (CVTs) are used for metering and protection in are used for metering and protection in high-voltage circuits. They are designed high-voltage circuits. They are designed to present negligible load to the supply to present negligible load to the supply being measured and to have a precise being measured and to have a precise voltage ratio to accurately step down voltage ratio to accurately step down high voltages so that metering and high voltages so that metering and protective relay equipment can be protective relay equipment can be operated at a lower potential. operated at a lower potential.

Basic Function Of the CVTBasic Function Of the CVT Where CHF is the equivalent Where CHF is the equivalent

rated capacitance for carrier rated capacitance for carrier communicationcommunication

* C1 : High Voltage * C1 : High Voltage capacitorcapacitor

* C2 : Intermediate Voltage * C2 : Intermediate Voltage CapacitorCapacitor * C1 / C2 ratio is such that * C1 / C2 ratio is such that

the required intermediate the required intermediate voltage can be achievedvoltage can be achieved

L : Inductance of the choke L : Inductance of the choke which is designed to which is designed to

* Prevent carrier signals * Prevent carrier signals from flowing into the from flowing into the transformer circuit.transformer circuit.

* Resonate with the * Resonate with the capacitor unit at 50 Hz which is capacitor unit at 50 Hz which is the rated frequency.the rated frequency.

D : Damping burden which is D : Damping burden which is provided across one of the provided across one of the secondary windings to prevent secondary windings to prevent terroresonance oscillations.terroresonance oscillations.

Tr : Transformer designed to Tr : Transformer designed to provide the required output provide the required output voltage at the desired burdenvoltage at the desired burden

Metering

Protection

D

1a

1n

2a

2n

HV

C1

C2

TrL

CHF