Capacitance potential device, equivalent Current-balance relay, directional type, 62 for circuit, 135 non-linear burdens, 139 standard line protection, 330 overcurrent type, 58 accuracy, 137 standard rated burdens, 136 Current biasing, for mho relay, 82 for offset Capacitor, series, effect on distance relaying, impedance relay, 77 to avoid distance-relay 367 misoperation on arcs, 346 Capacitor trippi Current compensation for ground distance relays,, 360 Carrier-current attenuation. 378 Current switching for distance relays, 368 Carrier-current-pilot relaying, see Pilot relaying, Current transformers,, accuracy calcula, 1 13 ASA accuracy classification, 121 burden, 114 Circuit breaker, by-passing, 292 standard for generator differential relaying, 198 capacities, 3 ratiocorrection-factor curves,, 116 secondary excitation curves,, 1 17 grounding the Circulating-current pilot relaying, 92, 94 secondaries of differentially connected CT's 291 overvoltage in secondary, 124 polarity Cold-load pickup 334 and connections, 126 proximity effect, 126 Cold-load restoration. 334 Current transformers, requirements for pilot elay ary leakage reactance, Compensated voltage, see Transformer 117.119.120 transient errors. 124.278.318 compensation types, 113 zero-phase-sequencecurrent shunt, 130.249 Constant-product characteristic, 38 D-c offset, effect on induction relays, 32, 39 Contact definitions. 17 overreach of distance relays, 82, 350 overreach of overcurrent relays, 308 time Contact races in pilot relaying, 91 constant. 279 Continuous pilot, 109 D-c relays, single-quantity, 22 directional, 24, 49 Control spring, 17 Differential relays, 63 see also Percentagedifferential relay Conventions. vector. 53 Directional-comparison relaying, for bus Corrosion, effect of polarity on, 19 rotection,277 principle of operation, 106 see also Line protection with pilot relays Coupling-capacitor description, 134 Directional control, of electromagnetic relays, Coupling-capacitor insulation coordination, 142 28 of single-quantity induction relays,, 32,57,310,313 Coupling-capacitor potential device, Bee capacitance potential device Directional-overcurrent relay, 57 INDEX2 I N D E X Capacitance potential device, equivalent circuit, 135 non-linear burdens, 139 standard accuracy, 137 standard rated burdens, 136 Capacitor, series, effect on distance relaying, 367 Capacitor tripping, 335 Carrier-current attenuation, 378 Carrier-current-pilot relaying, see Pilot relaying, carrier-current Circuit breaker, by-passing, 292 standard capacities, 3 Circulating-current pilot relaying, 92, 94 Cold-load pickup, 334 Cold-load restoration, 334 Compensated voltage, see Transformer compensation Constant-product characteristic, 38 Contact definitions, 17 Contact races in pilot relaying, 91 Continuous pilot, 109 Control spring, 17 Conventions, vector, 53 Corrosion, effect of polarity on, 19 Coupling-capacitor description, 134 Coupling-capacitor insulation coordination, 142 Coupling-capacitor potential device, Bee Capacitance potential device Current-balance relay, directional type, 62 for line protection, 330 overcurrent type, 58 Current biasing, for mho relay, 82 for offset impedance relay, 77 to avoid distance-relay misoperation on arcs, 346 Current compensation for ground distance relays,, 360 Current switching for distance relays, 368 Current transformers,, accuracy calcula , 113 ASA accuracy classification, 121 burden, 114 for generator differential relaying, 198 ratiocorrection-factor curves,, 116 secondary￾excitation curves,, 117 grounding the secondaries of differentially connected CT’s, 291 overvoltage in secondary, 124 polarity and connections, 126 proximity effect, 126 Current transformers, requirements for pilot relaying, 377 secondary leakage reactance, 117, 119, 120 transient errors, 124, 278, 318 types, 113 zero-phase-sequencecurrent shunt, - 130, 249 D-c offset, effect on induction relays, 32, 39 overreach of distance relays, 82, 350 overreach of overcurrent relays, 308 time constant, 279 D-c relays, single-quantity, 22 directional, 24, 49 Differential relays, 63 see also Percentagedifferential relays Directional-comparison relaying, for bus protection, 277 principle of operation, 106 see also Line protection with pilot relays Directional control, of electromagnetic relays,, 23 of single-quantity induction relays,, 32,57,310,313 Directional-overcurrent relay, 57