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4
EARTH FAULT PROTECTION
Earth faults are overcurrent faults where the fault current flows to earth. Earth faults are the most common type of
fault.
Earth faults can be measured directly from the system by means of:
●
A separate current Transformer (CT) located in a power system earth connection
●
A separate Core Balance Current Transformer (CBCT), usually connected to the SEF transformer input
●
A residual connection of the three line CTs, where the Earth faults can be derived mathematically by
summing the three measured phase currents.
Depending on the device model, it will provide one or more of the above means for Earth fault protection.
4.1
EARTH FAULT PROTECTION IMPLEMENTATION
Earth fault protection is implemented in the EARTH FAULT column of the relevant settings group. The element uses
quantities derived internally from summing the three-phase currents.
The product provides four stages of Earth Fault protection with independent time delay characteristics, for each
EARTH FAULT column.
Stages 1 and 2 provide a choice of operate and reset characteristics, where you can select between:
●
A range of IDMT (Inverse Definite Minimum Time) curves
●
DT (Definite Time)
This is achieved using the cells:
●
IN>(n) Function for the overcurrent operate characteristics
●
IN>(n) Reset Char for the overcurrent reset characteristic
where (n) is the number of the stage.
Stages 1 and 2 provide a Timer Hold facility. This is configured using the cells IN>(n) tReset
Stages 3 and 4 can have definite time characteristics only.
Earth fault Overcurrent IN> can be set to:
●
Permanently disabled
●
Permanently enabled
●
Enabled only if VT fuse/MCB fails
●
Enabled only if protection communication channel fails
●
Enabled if VT fuse/MCB or protection communication channel fail
●
Enabled if VT fuse/MCB and protection communication channel fail
Each stage can be individually inhibited with a DDB signal Inhibit IN>(n), where n is the stage number.
4.2
IDG CURVE
The IDG curve is commonly used for time delayed earth fault protection in the Swedish market. This curve is
available in stage 1 of the Earth Fault protection.
The IDG curve is represented by the following equation:
t
I
IN
Setting
op
e
=
−
>
5 8 1 35
.
.
log
where:
Chapter 9 - Current Protection Functions
P54A/B/C/E
202
P54xMED-TM-EN-1
Содержание P4A
Страница 2: ......
Страница 20: ...Contents P54A B C E xviii P54xMED TM EN 1 ...
Страница 27: ...CHAPTER 1 INTRODUCTION ...
Страница 28: ...Chapter 1 Introduction P54A B C E 2 P54xMED TM EN 1 ...
Страница 38: ...Chapter 1 Introduction P54A B C E 12 P54xMED TM EN 1 ...
Страница 39: ...CHAPTER 2 SAFETY INFORMATION ...
Страница 40: ...Chapter 2 Safety Information P54A B C E 14 P54xMED TM EN 1 ...
Страница 52: ...Chapter 2 Safety Information P54A B C E 26 P54xMED TM EN 1 ...
Страница 53: ...CHAPTER 3 HARDWARE DESIGN ...
Страница 54: ...Chapter 3 Hardware Design P54A B C E 28 P54xMED TM EN 1 ...
Страница 86: ...Chapter 3 Hardware Design P54A B C E 60 P54xMED TM EN 1 ...
Страница 87: ...CHAPTER 4 SOFTWARE DESIGN ...
Страница 88: ...Chapter 4 Software Design P54A B C E 62 P54xMED TM EN 1 ...
Страница 99: ...CHAPTER 5 CONFIGURATION ...
Страница 100: ...Chapter 5 Configuration P54A B C E 74 P54xMED TM EN 1 ...
Страница 120: ...Chapter 5 Configuration P54A B C E 94 P54xMED TM EN 1 ...
Страница 121: ...CHAPTER 6 CURRENT DIFFERENTIAL PROTECTION ...
Страница 122: ...Chapter 6 Current Differential Protection P54A B C E 96 P54xMED TM EN 1 ...
Страница 149: ...CHAPTER 7 AUTORECLOSE ...
Страница 150: ...Chapter 7 Autoreclose P54A B C E 124 P54xMED TM EN 1 ...
Страница 207: ...CHAPTER 8 CB FAIL PROTECTION ...
Страница 208: ...Chapter 8 CB Fail Protection P54A B C E 182 P54xMED TM EN 1 ...
Страница 219: ...CHAPTER 9 CURRENT PROTECTION FUNCTIONS ...
Страница 220: ...Chapter 9 Current Protection Functions P54A B C E 194 P54xMED TM EN 1 ...
Страница 244: ...Chapter 9 Current Protection Functions P54A B C E 218 P54xMED TM EN 1 ...
Страница 247: ...CHAPTER 10 VOLTAGE PROTECTION FUNCTIONS ...
Страница 248: ...Chapter 10 Voltage Protection Functions P54A B C E 222 P54xMED TM EN 1 ...
Страница 261: ...CHAPTER 11 FREQUENCY PROTECTION FUNCTIONS ...
Страница 262: ...Chapter 11 Frequency Protection Functions P54A B C E 236 P54xMED TM EN 1 ...
Страница 268: ...Chapter 11 Frequency Protection Functions P54A B C E 242 P54xMED TM EN 1 ...
Страница 269: ...CHAPTER 12 MONITORING AND CONTROL ...
Страница 270: ...Chapter 12 Monitoring and Control P54A B C E 244 P54xMED TM EN 1 ...
Страница 300: ...Chapter 12 Monitoring and Control P54A B C E 274 P54xMED TM EN 1 ...
Страница 301: ...CHAPTER 13 SUPERVISION ...
Страница 302: ...Chapter 13 Supervision P54A B C E 276 P54xMED TM EN 1 ...
Страница 312: ...Chapter 13 Supervision P54A B C E 286 P54xMED TM EN 1 ...
Страница 323: ...CHAPTER 14 DIGITAL I O AND PSL CONFIGURATION ...
Страница 324: ...Chapter 14 Digital I O and PSL Configuration P54A B C E 298 P54xMED TM EN 1 ...
Страница 336: ...Chapter 14 Digital I O and PSL Configuration P54A B C E 310 P54xMED TM EN 1 ...
Страница 337: ...CHAPTER 15 FIBRE TELEPROTECTION ...
Страница 338: ...Chapter 15 Fibre Teleprotection P54A B C E 312 P54xMED TM EN 1 ...
Страница 354: ...Chapter 15 Fibre Teleprotection P54A B C E 328 P54xMED TM EN 1 ...
Страница 355: ...CHAPTER 16 ELECTRICAL TELEPROTECTION ...
Страница 356: ...Chapter 16 Electrical Teleprotection P54A B C E 330 P54xMED TM EN 1 ...
Страница 366: ...Chapter 16 Electrical Teleprotection P54A B C E 340 P54xMED TM EN 1 ...
Страница 367: ...CHAPTER 17 COMMUNICATIONS ...
Страница 368: ...Chapter 17 Communications P54A B C E 342 P54xMED TM EN 1 ...
Страница 439: ...CHAPTER 18 CYBER SECURITY ...
Страница 440: ...Chapter 18 Cyber Security P54A B C E 414 P54xMED TM EN 1 ...
Страница 457: ...CHAPTER 19 INSTALLATION ...
Страница 458: ...Chapter 19 Installation P54A B C E 432 P54xMED TM EN 1 ...
Страница 469: ...5 2 CASE DIMENSIONS 60TE E01409 Figure 197 60TE case dimensions P54A B C E Chapter 19 Installation P54xMED TM EN 1 443 ...
Страница 471: ...CHAPTER 20 COMMISSIONING INSTRUCTIONS ...
Страница 472: ...Chapter 20 Commissioning Instructions P54A B C E 446 P54xMED TM EN 1 ...
Страница 513: ...CHAPTER 21 MAINTENANCE AND TROUBLESHOOTING ...
Страница 514: ...Chapter 21 Maintenance and Troubleshooting P54A B C E 488 P54xMED TM EN 1 ...
Страница 530: ...Chapter 21 Maintenance and Troubleshooting P54A B C E 504 P54xMED TM EN 1 ...
Страница 531: ...CHAPTER 22 TECHNICAL SPECIFICATIONS ...
Страница 532: ...Chapter 22 Technical Specifications P54A B C E 506 P54xMED TM EN 1 ...
Страница 558: ...Chapter 22 Technical Specifications P54A B C E 532 P54xMED TM EN 1 ...
Страница 559: ...APPENDIX A ORDERING OPTIONS ...
Страница 560: ...Appendix A Ordering Options P54A B C E P54xMED TM EN 1 ...
Страница 565: ...APPENDIX B SETTINGS AND SIGNALS ...
Страница 566: ...Appendix B Settings and Signals P54A B C E P54xMED TM EN 1 ...
Страница 790: ...Appendix B Settings and Signals P54A B C E B224 P54xMED TM EN 1 ...
Страница 835: ...APPENDIX C WIRING DIAGRAMS ...
Страница 836: ...Appendix C Wiring Diagrams P54A B C E P54xMED TM EN 1 ...
Страница 849: ......