1 Chapter Overview 359
2 Phase Fault Overcurrent Protection 360
2.1 POC Implementation 360
2.2 Directional Element 360
2.3 POC Logic 362
3 Negative Sequence Overcurrent Protection 363
3.1 Negative Sequence Overcurrent Protection Implementation 363
3.2 Directional Element 363
3.3 NPSOC Logic 364
3.4 Application Notes 364
3.4.1 Setting Guidelines (Current Threshold) 364
3.4.2 Setting Guidelines (Time Delay) 364
3.4.3 Setting Guidelines (Directional element) 364
4 Earth Fault Protection 366
4.1 Earth Fault Protection Implementation 366
4.2 IDG Curve 366
4.3 Directional Element 367
4.3.1 Residual Voltage Polarisation 367
4.3.2 Negative Sequence Polarisation 368
4.4 Earth Fault Protection Logic 369
4.5 Application Notes 369
4.5.1 Residual Voltage Polarisation Setting Guidelines 369
4.5.2 Setting Guidelines (Directional Element) 369
5 Sensitive Earth Fault Protection 371
5.1 SEF Protection Implementation 371
5.2 EPATR B Curve 371
5.3 Sensitive Earth Fault Protection Logic 372
5.4 Application Notes 373
5.4.1 Insulated Systems 373
5.4.2 Setting Guidelines (Insulated Systems) 374
6 High Impedance REF 376
6.1 High Impedance REF Principle 376
7 Thermal Overload Protection 378
7.1 Single Time Constant Characteristic 378
7.2 Dual Time Constant Characteristic 378
7.3 Thermal Overload Protection Implementation 379
7.4 Thermal Overload Protection Logic 379
7.5 Application Notes 379
7.5.1 Setting Guidelines for Dual Time Constant Characteristic 379
7.5.2 Setting Guidelines for Single Time Constant Characteristic 381
8 Broken Conductor Protection 382
8.1 Broken Conductor Protection Implementation 382
8.2 Broken Conductor Protection Logic 382
8.3 Application Notes 382
8.3.1 Setting Guidelines 382
Chapter 14 Voltage Protection Functions 385
1 Chapter Overview 387
2 Undervoltage Protection 388
2.1 Undervoltage Protection Implementation 388
2.2 Undervoltage Protection Logic 389
2.3 Application Notes 390
2.3.1 Undervoltage Setting Guidelines 390
3 Overvoltage Protection 391
3.1 Overvoltage Protection Implementation 391
3.2 Overvoltage Protection Logic 392
P446SV Contents
P446SV-TM-EN-1 ix
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