Table Of Content

U. A. Bakshi M. V. Bakshi MRelalel(ocl i ablb)i(eclile)etcmatlatce Table of Contents 14Lintroduction. 4.2 Functions of Protective Relaying... 1.3 Protective Zones 1.4 Primary and Backup Protection FIX Concept of Bacup Relay 414.2 Methods of Backup Protecton._ 1.8 Classification of Protective Relays......... 1-15, “Hirt Ebotoneacets ivcton Tipe Retr ae 182 nduten Type Rely... ieee eT 1.8.3 Directional Type Retays. ai wei 4-16 1.8.4 Relays Based on Timing = ee 185 Distance Tipe Relays 16 186 Dire Tipe Relays 16 1.8.7 Other Types of Relays... 117 4.9 Terminologies used in Protective Relaying. 4.17 1.12.1 Wound Type Current Transformer. 12 CP TRIE TP RERIE SS 1.12.2 Bar Type Curent Transformer (ote {43 Why Secondary of C.T. Should not be Open 2. 1-24 4.14 Potential Transformers (P.T.) sss ss ABB Li Const r 1.15 Comparison of C.T. and PT. ‘L104 Ratio Exor 1.16.2 Phase Angle Emor . a {116.3 Reduction of Ratio and Phase Angi Ears 1.17 Advantages and Disadvantages of Instrument Transformers... Review Question: - . 2.4 Jnttoduction 264 2.1.1 Basic Tp Grout Operation. 2 2:2 Avan Switch TT) 2.2 Tripping Schemes in Circuit Breaker .. . arr) Zt Relays wit ace Type Coast = = 3 12.22 Relay with Beak Type Contact 24 2.3 Electromagnetic Atvacton RAYS onsen BB ‘TT Airaid Armature Tyoo Relay cd 232 Solenoid and Punger Type Relay 21 233 Operation Prince of Electromagnetic Atracton Rela 28 23.4 Advantages of Electomagnetic Rela. - - 20 235 Disedkantages of Elecvomagneic Relays 210 236 Aaplcatons of Electromagnetic Relays 240 24 Induction Type Relays ar Sr] 4.1 Torque Equation or Induction Type Relays ai] 2.4.2 Shaded Pole Tye induction Relay 2:3 2.4.3 Wattour Meer Type induction Rey 245 2.4 inducion Cup Type Rel 236 2.5 Nondirectional induction Type Overcurrent Relay ses DAT 5 Tine Caneel Chara. ai] 252 Operation 219 2.6 Directionat Power Rela) . en 2-2D 2.7 Directional induction Type Overcurrent Rela 23 T Opera 2B 2.22 Diectonal Characters. 28 2.8 Thermal Relays i 2.28 2.9 Universal Relay Torque Equation .. 2.1 Curent 3.2.2 Based Boar Relay or Percentage Dfereal Relay 412.3 Vologe Balance Differential Rola (3.3. Bushar Protection 3.1 Bushar Fauts 3.4 Frame Leakage Protection of Busbar 3.5 Circulating Current Protection of Busbar 3.6 High Impedance Differential Protection of Busba ‘3.7 Difficulties in Busbar Protection Review Questions 3.9 4.1 Distance Relays. “2 \nPaee tase ere 142.2 Operating Characters 142.3 Operating Characteristics on RX Diagram. 424 Disadvantages of lain Impedance Relay 4.2.5 Directional impedance Relay. _ 4.2.6 Use of Impedance Relay for Transmission Line Protection. 47 4.3 Rei nce ee wactance Relay. 43.2 Torque Equation 4.3.3 Operating Characteristics. 434 Digadarioges cscs 4.4 Mho Relay ‘or Admitance Rel Relay lay. 44.2 Torque Equation 44.3 Operating Characteristics... 4.5 Classification of Distance Rel ‘45.1 Definite Distance Type Impedance Sere BER 5.21 Stator Faults S211Phacoteeam route gg S2i2Phasemprasaraute gg 4.3 State te Turn Eats 52 5.22 Rotor aus, 53 ‘5.2.3 Abnormal Running Conditions 53 $23.1 Overeating 53 5232 0verpeadng ? ss S233 Urbworeed Loading, =e ar $234 54 4 Basic Pi 5.5 Merz-Price Protection of Altemator Stator Windings .... 56.1 Effect of Earth Resistance on % of Winding Unprotected. S12 S.7 Unrestricted Earth Fault Protection. SI S.8Balanced Earth Fault Protection 00 6.9 100% Earth Fault Protection IB 5.10 Stator Protection Against Interturn Faults... ditniaA® 5.11 Rotor Earth Fault Protection 5.20 5-22 523 5.12 Protection Against Loss of Excitation. 5.13 Negative wence Relays.. 5.14 Protection Against Unbalanced Loading. Examples with Solutions . 74.1 Harmonie Restraint and Harmonic Blocking sideees TZ 7.5 Frame Leakage Protection. 8.2 Phase Comparison Method of Carrier Current Protection 8.3 Advantages of Carrier Current Protection... 844 Static Relays. 85 Basic Elements of a Static Relay 85.1 Input Element. 8.5.2 Measuring Element. . 85.3 Output Element. 8.5.4 Feed Element. oo 86 of Static and EI tic Seri 2 emer 8.6.2 Limitations of Static Relays — 87 Semiconductor Devices used in Stas Relays. 8.8 Static Time Current Relay. 8.8.2 Static Instantaneous Overcurrent Relay... . : 8.8.3 Inverse Time-Current Relay 2 ereeri £18 8.9 Directional Static Overcurrent 8.10 Static Differential Relay.. 22. nation ofA 9.2.1.1 By High Vokge Gan. 9212 By nerease of Tempera sas 92 Formation of an Are: 22 82 2 92 923 Arc Extinction 9.23.1 High Resistance Method lie B il 9.3 D.C. Circuit Breaking 9.4 AC. Circuit Breaking. gf ul 9.6 Current Interruption in A.C. Circuit Breakers .. POLES AES ES EEG a 9.7 Transient Recovery Voltage... ssnnnnen BAZ 98 Effect of Diferent Parameters on Transiont Recovery Voltage (TRV). 8-13 9.8.1 Effect of Natal Frequency on TRV o4 282 Ffiect of Power Factor on TRV tg 9.9 Recovery Voltage. sense 916 Efe of Rare bits Ray Vas pa 9.9.2 Effect of Armature Reaction on Recovery Vohage 346 8.10 Single Frequency Transient snsnnnee AT 9.11 Double Frequency Transient 947 9.12 Derivation of Rate of Rise of TRV... 948 9.12.1 Exoression for Maximum Vale of Rastikng Votage E_, and Corresponding Time &_. 24 9.122 Expression for RARV and Maximum RRRV 921 8.12.3 Frequency of Cscllation of Resting Voltage (Transient) 92 8.124 Restrking Votage Under Various Condtons 922 8.125 First Polo to Clear Factor. 92 9.13 Interruption of Capacitive Currents saa O27 8.14 Current Chopping (Interruption of Low Magnetizing Current)... 9-29 9.15 Resistance Switching... 932 9.16 Arc Extinction... . ss nnnnnnnnni 2935 9.16.1 High Resistance inierupion 838 9.162 Low Resistance or Curent Zoro Inienuption 936 9.16: Afficiat Curent Zero Intemution 936 9.17 lonization of Gases 9-96 2.171 Thermal lonzaton rR 8.172 lonizaton by Colision 37 9.173 Thermal Emission om Surace of Contacts 937 8.174 Secondary Emission at Contact Surface 937 9.17.5 Field Emission or 9.17. Photoemission. oar 9.18 Deionization ne - 9-37 9.18 Recombination, 337 9.18.2 Dison 337 9.18.4 Conduction of Heat 238 9.19 Arc Formation n238 9220 Hoh Raslotnes fe tnartion Meth nore 8S 9.202 Splting of Are. 338 $9.20;3 Cooling of Arc $39 EES GLEE TAME LI EE Sb 9.21 Low Resistance or Zero Point Extinction .. 9.22 Arc Interruption Theories ... . 922 OF Senay er 9.22.2 Cassie's Theory Examples with Solutions Review Questions. FEY i 5 10-4 Introduction 10-4 10.2 Requirements of Circuit Breaker... 10-4 10.3 Basic Action of a Circuit Breaker 0 tt 10.4 Classification of Circult Breakers 000 ag 10.5 Air Blast Circuit Breakers 10.3 ‘10.6.1 Constncion olan A Blast Gucut Beaker 0 40.52 Working oases 105 105.21 Goss Bast Type 108 105.22 Al Blest Type 108 10.5.3 Compressed Ac System for Ai Blast Circuit Breaker. sca eee OD NOSAAQVONOQES este se seers eens m 10-19 10.55 Disadvantages 04 10.56 Applications 10-10 i Break Circult 8 10.631 Consucton ott 10.62 Working. 1042 10.63 Aoplcations. 10-13 10,7 Sulphur Hexafturide (SFs) Crit Breaker 19-13 107 1.1 Physical Properties 10.14 107.12 Chemical Properties tou 07.13 Dielectric Properties ou 10.7.2 Construction of Non-Putler Type SF Breaker. 10-16 10.721 Werkng 1017 10.7.3 Singe Pressure Puller Type SF, Creult Breaker 10-18 10.7 4 Double Pressure Type SFe Creat Breaker. 10-19 10.75 Advantages of SF Creut Breaker i 10-20 10.76 Disadvantages. 10:20 10.7.7 Applications. 1021 10.8 Vacuum Circuit Breakers. oneness A OBT 108.1 Ecce Breakdown a igh Vacusm 1021 10.6.2 Constructican 103 10.83 Working 1023 108.4 Advantages 1024 1085 Disadvantages 1024 108.6 Recovery Strength Characteristics 10.25 10387 Appcatons 1025 10.9.Oil Circuit Breakers. 10. 10.9.1 Plain Break Ol Circuit Breaker 1091.1 Seg Break OF Creut Bese 10% MO12mble Beak OLR tga 13 e TT E 14 Poin 4 1039 10915 Disseantages of Phin Bik 0% Cet Braker 1039 109.18 Agpkabons 1039 10.9.2 Self Generated Pressure Qi Citcut Breaker 1092. isin Elon Pot 1031 109.22 Cos it Exonon Pot 1031 10923 Set CompensaiedExpesion Pot 1092 1092404 last Exon Pt 1033 10.10.2 Operation... 10-38 10.104 Advantages 10,10.5 Disadvantages. 10.106 Applications... 10.11 HVDC Circuit Breaker 10.12 Selection of Circuit Breaker .. . se 10-38 10.13 Circuit Breaker Ratings...... sons soonnel 40 40.13. Rated Voltage oat 10.132 Rated insuition Level. 1041 1013.3 Rated Coment 40.41 10.134 Rated Frequency... 10-44 10.13.5 Rated Duration of Short Gieut we 1042