Page 408 - Practical Power System and Protective Relays Commissioning

396 Index

Time scheduling and resource planning of vector group of three-phase transformer,
commissioning of substations, 19 56f,57f
Time setting multiplier (TMS), 195 vector group test, 60 61, 61f
Time/current grading principles Transient performance CT (TP CT), 113 115
current, discrimination by, 203 TPS Class, 113
current and time, discrimination by, 204 TPX Class, 113
time, discrimination by, 203 TPY Class, 113 114
TL. See Transmission line (TL) TPZ Class, 113 115
TM. See Time multiplier (TM) Transient stability
TMS. See Time setting multiplier (TMS) limit, 40
Total current, 64 65 of synchronous generators, 40
Towers, 69 Transmission line (TL), 69, 191 192, 210,
Toxic arc byproducts, 91 216
TP CT. See Transient performance CT (TP autoreclosing for, 232 234
CT) high voltage DC power systems
Transactors, 115 transmission, 78 83
Transformer protection, 269 270, 294 overcurrent protection, 282 283
Buchholz protection, 272 273 overhead AC lines, 69 70
comparison of high-and low-impedance testing and commissioning of extra-high-
differential protection, 279 voltage and high-voltage cables,
differential protection, 273 275 72 78
examples of transformer differential underground cables, 70 72
protection connections, 279 Transmission system, 1
Dy11 transformer differential protection, Transport control protocol (TCP), 180t, 183
280f Transportation, 58
Y y0 auto-transformer differential Trip
protection connections, 280f logic of relay, 238, 241f
IED, 198 199 test, 354 355
system earthing, 277 279 time test, 346
testing and commissioning trip-free CB feature, 93
primary injection test, 347 349, 348f Turbogenerators, 35 36
secondary injection tests, 344 347 Two-winding transformers, 275 277, 277f
transformer differential protection, 344 sequence impedances, 166, 167f
zero-sequence circuits of transformers,
275 277
Transformer(s), 2 U
construction, 49 50 Unbalance effects on zero-sequence
cooling system, 50 51, 52t protection, 233
differential protection, 367 368 Unbalance protection, 250
earth fault protection, 272 Unbalanced phasors, 165
efficiency, 63 Undercurrent relay, 323
impedance, 51 Underfrequency protection, 247
inrush current, 270 Underground cables, 70 72
oil breakdown test, 64 high-voltage cables, 72
overcurrent protection, 271, 283 284, 283f Underreach scheme, 221 222
overload protection, 271 Unearthed systems, 279
percentage impedance, 166, 167f Unit power factor, 205
storage, 58 Unit protections, 260 261
theory, 51 58, 53f application of differential protection,
and overexcitation, 56 58 262
three-phase power transformer balanced circulating current system, 261f
connection vector group, 55f balanced voltage system, 262f