seminar on numerical relay.pptx

7/22/2019 Seminar on NUMERICAL RELAY.pptx

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NUMERICALRELAY

Submitted by

MD ASAHAD S7 EEE

ROLL NO:-63



OVERVIEW• INTRODUCTION TO RELAYS

• NUMERICAL RELAYS

• REQUIREMENTS OF NUMERICAL RELAYS

• BLOCK DIAGRAM

• RELAY HARDWARE STRUCTURE

• ADVANTAGES AND DISADVANTAGES

• APPLICATIONS OF NUMERICAL RELAYS

• CONCLUSION



INTRODUCTION TORELAYS

1.ELECTROMECHANICAL RELAYS :

MECHANICAL FORCES CAUSES OPERATION OFRELAY CONTACT IN RESPONSE TO A SIGNAL.

CAN BE CLASSIFIED TO SEVERAL TYPES –

ATTRACTED ARMATURE

MOVING COIL INDUCTION THERMAL



2. STATIC RELAYS :

ABSENCE OF MOVING PARTS TO CREATE RELAY

CHARACTERISTICS.

USES STATIC ELEMENTS LIKE TRANSISTORS, DIODES,LOGIC GATES & ICS FOR RELAY CHARACTERISTIC.

OUTPUT CONTACTS ARE STILL THROUGH ATTRACTEDARMATURE RELAYS



3. NUMERICAL RELAYS

ANALOGUE CIRCUITS ARE REPLACED WITH

MICROPROCESSORS TO IMPLEMENT RELAYFUNCTIONS.

MICROPROCESSOR USES PROTECTION ALGORITHMS& OTHER COMPUTATIONAL FUNCTIONS FOR

CHARACTERISTIC GENERATION.



Block Diagram



Fundamental requirements of numerical

relay

• SPEED

• SENSITIVITY

• RELIABILITY

• SELECTIVITY

• SIMPLICITY

• ECONOMY



TYPICAL NUMERICAL RELAY HARDWARE

VA G

ALVANI

C ISOL

ATION

VB

VC

IA

IB

IC

AN

TIALIS

ING FI

LTERS

S

AMPLE

& HOLDCKT

MU

LTIPLEXERE

ADC MICROPROCESSOR

E2 PROMROM RAM

DIGITAL I/O

KEYBOARD &DISPLAY

COMMUNICATIONOPTO

ISOLATOR

CB STATUS

REED

REALY CB TRIP



RELAY HARDWARESTRUCTURE

• GALVANIC ISOLATION MODULE :

CONVERTS CURRENT SIGNAL TO VOLTAGE &ELECTRICALLY ISOLATES THE SIGNAL BETWEENDIGITAL & ANALOGUE CIRCUIT.

• ANTIALIAS FILTERS :SAMPLING FREQUENCY SHOULD BE MORE THANTWICE THAT OF HIGHEST FREQUENCY OF INTEREST.

• SAMPLE & HOLD CIRCUIT :ANALOGUE TO DIGITAL CONVERSATION REQUIRESSOME FINITE TIME(25µS). THIS CKT HOLDS THE SIGNALFOR PROPER CONVERSATION.



• MULTIPLEXER : USES A SINGLE MICROPROCESSOR ANALOGUE

MULTIPLEXER FOR SEQUENTIAL SELECTION OFSIGNALS

• A/D CONVERTER:CONVERTS TO DIGITAL SIGNALS FOR HANDLING IN

MICROPROCESSOR.

• MICROPROCESSOR : DIGITAL SIGNAL HANDLED FOR ALGORITHMS &SCHEME LOGIC FUNCTION.

• ROM : CONTAINS THE RELAYING PROGRAMME



• RAM : USED FOR STORING SAMPLED QUANTITIES &

INTERMEDIATE PRODUCTS IN RELAYING ALGORITHMS.

• E2PROM : USED FOR STORING RELAY SETTINGS.

• KEYBOARD & DISPLAY :Used for change in settings & display functions.

• DIGITAL I/O :Device takes the breaker status through optoisolators & issues trip commands through reedrelays.



• COMMUNICATION :

Helps to communicate with other relays orwith the system.

• POWER SUPPLY :

In built switching mode power supplymodules are used for quality aux. supply.



ADVANTAGES OFNUMERICAL REALYS

• FLEXIBILITY IN WIDE PARAMETER ADJUSTMENT.

• PROGRAMMABLE FUNCTION SETTING

• MULTIPLE FUNCTIONS BY THE SAME RELAY• INTERNAL FAULT DIAGNOSIS.

• MEMORY & RECORDING FUNCTION

•

PROGRAMMABLE CT & PT RATIO• DIGITALLY COMMUNICATION FACILITY



DISADVANTAGES WITHNUMERICAL RELAYS

• HIGH INITIAL COST

• REQUIRES STABLE POWER SUPPLY.

• IF USED FOR MULTIFUNCTION IN A SINGLEFEEDER, FAILURE OF RELAY MAY CAUSE TOTAL

PROTECTION FAILURE FOR THE EQUIPMENT.

• REQUIRES EMC ENVIRONMENT.



Applications •

Control a high-voltage circuit with a low-voltage signal, as in some types of modems

or audio amplifiers,

• Control a high-current circuit with a low-

current signal, as in the starter solenoid of an

automobile

• Detect and isolate faults on transmission and

distribution lines by opening and closing

circuit breakers (protection relays)



CONCLUSIONNUMERICAL RELAYS NEED TO BE

INCORPORATED IN THE DESIGN STAGE OF

THE PLANT WHICH WILL HELP TO

REDUCE THE PANEL SIZE.

PANEL WIRING COST.

POPULATION OF RELAYS IN THE PLANT.

MEET SPACE CONSTRAINTS.

REDUCE THE QUANTUM OF SPARES.



REFERENCES• A comprehensive approach for numerical relay

system evaluation and test : Sato, H. ; MitsubishiElectr. Corp., Japan ; Takano, T. ; Inoue, S. ; Oda, S.

• Commissioning numerical relays : Closson, J.R. ;Basler Electr. Co., Highland, IL, USA ; Young, M.

• Issues and opportunities for testing numerical relays :Sachdev, M.S. ; Power Syst. Res. Group,Saskatchewan Univ., Saskatoon, Sask., Canada ;

Sidhu, T.S. ; McLaren, P.G.



THANK YOU

seminar on numerical relay.pptx

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