The diagram illustrates the method of discrimination when the real (cos
f
) component is considered. Faults close to
the polarising voltage will have a higher magnitude than those close to the operating boundary. In the diagram,
we assume that the current magnitude I is in both the faulted and non-faulted feeders.
●
For the active component Icos, the criterion for operation is: Icos
f
> ISEF>(n) current
●
For the reactive component Isin, the criterion for operation is: Isin
f
> ISEF>(n) current
Where ISEF>(n) current is the sensitive earth fault current setting for the stage in question
If any stage is set to non-directional, the element reverts back to normal operation based on current magnitude I
with no directional decision. In this case, correct discrimination is achieved by means of an Icos characteristic as
the faulted feeder will have a large active component of residual current, whilst the healthy feeder will have a
small value.
For insulated earth applications, it is common to use the Isin characteristic.
All of the relevant settings can be found under the SEF PROTECTION column.
8.4.3
DIRECTIONAL SEF LOGIC
V04005
SEF Options
I2H Any Start
ISEF> Blocking
2H Blocks ISEF>1
Inhibit SEF
ISEF>1 Current
VTS Slow Block
ISEF> Blocking
VTS Blks ISEF>1
ISEF> VNpol Set
Directional
check
ISEF>1 Direction
ISEF>1 CharAngle
ISEF>1 Timer Blk
PN> Setting
SEF Options
Wattmetric
ISEF>1 Start
ISEF>1 Trip
&
IDMT/DT
Timer Settings
&
&
&
&
&
Note: This diagram does not show all stages. Other
stages follow similar principles.
ISEF>1 TripAngle
ISEF
ISEFsin(phi)
ISEFcos(phi)
VN.ISEF.cos phi
VN
Figure 60: Directional SEF with VN polarisation (single stage)
The sensitive earth fault protection can be set IN/OUT of service using the appropriate DDB inhibit signal, which
can be operated from an opto-input or control command. VT Supervision (VTS) selectively blocks the directional
protection or causes it to revert to non-directional operation. When selected to block the directional protection,
VTS blocking is applied to the directional checking which effectively blocks the start outputs as well.
The directional check criteria are given below for the standard directional sensitive earth fault element:
●
Directional forward: -90° < (angle(IN) - angle(VN + 180°) - RCA) < 90°
●
Directional reverse: -90° > (angle(IN) - angle(VN + 180°) - RCA) > 90°
Chapter 6 - Current Protection Functions
P24xM
134
P24xM-TM-EN-2.1
Summary of Contents for P24DM
Page 2: ......
Page 17: ...Appendix C Wiring Diagrams 467 P24xM Contents P24xM TM EN 2 1 xv...
Page 18: ...Contents P24xM xvi P24xM TM EN 2 1...
Page 24: ...Table of Figures P24xM xxii P24xM TM EN 2 1...
Page 25: ...CHAPTER 1 INTRODUCTION...
Page 26: ...Chapter 1 Introduction P24xM 2 P24xM TM EN 2 1...
Page 37: ...CHAPTER 2 SAFETY INFORMATION...
Page 38: ...Chapter 2 Safety Information P24xM 14 P24xM TM EN 2 1...
Page 51: ...CHAPTER 3 HARDWARE DESIGN...
Page 52: ...Chapter 3 Hardware Design P24xM 28 P24xM TM EN 2 1...
Page 66: ...Chapter 3 Hardware Design P24xM 42 P24xM TM EN 2 1...
Page 67: ...CHAPTER 4 SOFTWARE DESIGN...
Page 68: ...Chapter 4 Software Design P24xM 44 P24xM TM EN 2 1...
Page 77: ...CHAPTER 5 CONFIGURATION...
Page 78: ...Chapter 5 Configuration P24xM 54 P24xM TM EN 2 1...
Page 94: ...Chapter 5 Configuration P24xM 70 P24xM TM EN 2 1...
Page 95: ...CHAPTER 6 CURRENT PROTECTION FUNCTIONS...
Page 96: ...Chapter 6 Current Protection Functions P24xM 72 P24xM TM EN 2 1...
Page 188: ...Chapter 6 Current Protection Functions P24xM 164 P24xM TM EN 2 1...
Page 189: ...CHAPTER 7 RESTRICTED EARTH FAULT PROTECTION...
Page 190: ...Chapter 7 Restricted Earth Fault Protection P24xM 166 P24xM TM EN 2 1...
Page 201: ...CHAPTER 8 CB FAIL PROTECTION...
Page 202: ...Chapter 8 CB Fail Protection P24xM 178 P24xM TM EN 2 1...
Page 215: ...CHAPTER 9 CURRENT TRANSFORMER REQUIREMENTS...
Page 216: ...Chapter 9 Current Transformer Requirements P24xM 192 P24xM TM EN 2 1...
Page 224: ...Chapter 9 Current Transformer Requirements P24xM 200 P24xM TM EN 2 1...
Page 225: ...CHAPTER 10 VOLTAGE PROTECTION FUNCTIONS...
Page 226: ...Chapter 10 Voltage Protection Functions P24xM 202 P24xM TM EN 2 1...
Page 245: ...CHAPTER 11 FREQUENCY PROTECTION FUNCTIONS...
Page 246: ...Chapter 11 Frequency Protection Functions P24xM 222 P24xM TM EN 2 1...
Page 261: ...CHAPTER 12 POWER PROTECTION FUNCTIONS...
Page 262: ...Chapter 12 Power Protection Functions P24xM 238 P24xM TM EN 2 1...
Page 265: ...CHAPTER 13 MONITORING AND CONTROL...
Page 266: ...Chapter 13 Monitoring and Control P24xM 242 P24xM TM EN 2 1...
Page 294: ...Chapter 13 Monitoring and Control P24xM 270 P24xM TM EN 2 1...
Page 295: ...CHAPTER 14 SUPERVISION...
Page 296: ...Chapter 14 Supervision P24xM 272 P24xM TM EN 2 1...
Page 312: ...Chapter 14 Supervision P24xM 288 P24xM TM EN 2 1...
Page 313: ...CHAPTER 15 DIGITAL I O AND PSL CONFIGURATION...
Page 314: ...Chapter 15 Digital I O and PSL Configuration P24xM 290 P24xM TM EN 2 1...
Page 327: ...CHAPTER 16 COMMUNICATIONS...
Page 328: ...Chapter 16 Communications P24xM 304 P24xM TM EN 2 1...
Page 386: ...Chapter 16 Communications P24xM 362 P24xM TM EN 2 1...
Page 387: ...CHAPTER 17 CYBER SECURITY...
Page 388: ...Chapter 17 Cyber Security P24xM 364 P24xM TM EN 2 1...
Page 405: ...CHAPTER 18 INSTALLATION...
Page 406: ...Chapter 18 Installation P24xM 382 P24xM TM EN 2 1...
Page 419: ...CHAPTER 19 COMMISSIONING INSTRUCTIONS...
Page 420: ...Chapter 19 Commissioning Instructions P24xM 396 P24xM TM EN 2 1...
Page 443: ...CHAPTER 20 MAINTENANCE AND TROUBLESHOOTING...
Page 444: ...Chapter 20 Maintenance and Troubleshooting P24xM 420 P24xM TM EN 2 1...
Page 453: ...CHAPTER 21 TECHNICAL SPECIFICATIONS...
Page 454: ...Chapter 21 Technical Specifications P24xM 430 P24xM TM EN 2 1...
Page 486: ...Chapter 21 Technical Specifications P24xM 462 P24xM TM EN 2 1...
Page 487: ...APPENDIX A ORDERING OPTIONS...
Page 488: ...Appendix A Ordering Options P24xM 464 P24xM TM EN 2 1...
Page 491: ...APPENDIX B SETTINGS AND SIGNALS...
Page 493: ...APPENDIX C WIRING DIAGRAMS...
Page 494: ...Appendix C Wiring Diagrams P24xM 468 P24xM TM EN 2 1...
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