Page 403 - Practical Power System and Protective Relays Commissioning

Index 391

Overall differential protection, 236 Phase unbalance protection, 323
Overcurrent protection (OC protection), 242, Phase-to-earth faults, 227
242f. See also Feeder backup Phase-to-phase fault, 171, 171f, 176f, 177, 227
overcurrent protections Phasing check, 72, 73f
settings, 281 282 Phasing process, 367
of high-voltage transmission line, 282f Photovoltaic systems (PV systems), 32, 33f
transmission line overcurrent protection, Pickup/drop off test, 328
282 283 Pilot wire protection, 262 263
transformer, 271, 283 284, 283f PLC. See Power line carrier (PLC)
Overcurrent relays. See also Distance relays; Plug setting multiplier (PSM), 195, 282 283
Protection relays Polarity test (PT), 119, 130 131, 130f, 153
directional relays, 204 208 Polarization Index Test, 43
earth fault protection, 204 Polarizing signal, 204
IEC curves and ANCI/IEEE curves Pole slipping protection. See Out-of-step
overcurrent relay characteristic, 209 protection
nondirectional overcurrent and earth fault Poly-phase transformers, 54 55
protection, 202 203 Polyvinyl chloride (PVC), 71
principles of time/current grading, 203 204 Positive sequence, 163, 165f
secondary injection tests, 327 331 Postfault times, 142
Overexcitation, 56 58 POTT. See Permissive overreach transfer trip
Overfluxing, 58 (POTT)
Overhead Power
AC lines, 69 70 angle of synchronous machines, 41
electrical characteristics of AC conductors, 69
transmission lines, 69 70 factor relay protection, 248
transmission, 69 sources, 157
Overloading protection, 247, 250, 311, 323 Power line carrier (PLC), 263 265
transformer, 271 Power stations
OVT. See Optical voltage transformer (OVT) fault recorders in, 141
Oxygen content, 91 generator connection in, 41, 42f
Power swing blocking
relay, 228, 229f
P settings, 293 294
Pantograph disconnect switch, 133, 136f Power system, 1, 3f, 189
Paper-insulated oil-filled cables, 72 components, 2
Parallel lines, distance protection setting for, theory, 19
219 220, 219f, 220f distribution system, 1
Partial discharge measurement, 66 67 fault calculations
Percentage impedance (Z%), 166 basic system relationships, 163
of transformer, 53, 53f sequence impedance networks, 165 170,
Permissive overreach scheme, 223, 223f, 224f 166f
weak infeed in, 220, 221f symmetrical and unsymmetrical
Permissive overreach transfer trip (POTT), components, 163 165
220 symmetrical three-phase fault analyses,
Permissive underreach scheme, 222, 222f, 170 173
223f worked examples, 173 177
Petersen coil earthing, 279 IEEE device numbers and functions for
Phase error, 123 124 switchgear apparatus, 2 4
Phase fault protection, 321 loads, 1 2
-Phase rotation protection, 323 power generation, 1
Phase sequence test, 44 system voltages, 2
Phase to phase to earth fault, 171 172, 172f transmission, 1, 210