3.5.2
DIRECTIONAL OVERCURRENT LOGIC
&
POC1 I>1 TBlk
POC1 I>1 Start A
POC1 I>1 Trip
&
POC1 IH2 Any St
I> Blocking
&
POC1 IA 2H Start
I> Blocking
&
V00689
2H Blocks I>1
2H Blocks I>1
2H 1PH Block
Timer Settings
IA
I> Threshold
IDMT/DT
VTS Slow Block
I> Blocking
VTS Blocks I>1
IA
&
Directional
check
I>1 Direction
Non-Directional
Directional FWD
Directional REV
VAB
Notes: Shown for phase A only . Same principle applies for phases B and C .
This diagram does not show all stages . Other stages follow similar principles.
Figure 95: Directional overcurrent logic diagram
The directional overcurrent logic works the same way as non-directional logic except that there is a Directional
Check function, based on the following criteria:
●
Directional forward: -90° < (angle(I) - angle(V) - RCA) < 90°
●
Directional reverse: -90° > (angle(I) - angle(V) - RCA) > 90°
The polarising voltages for each phase are as follows:
Phase of Protection
Operate Current
Polarising Voltage
A Phase
IA
VBC
B Phase
IB
VCA
C Phase
IC
VAB
When the element is selected as directional, blocking of the Voltage Transformer Supervision (VTS Block) is
available (I>Blocking cell). When the relevant bit is set to 1, operation of the VTS will block the stage if
directionalised. When set to 0, the stage will revert to non-directional on operation of the VTS.
3.6
APPLICATION NOTES
3.6.1
SETTING GUIDELINES
The overcurrent inverse time characteristic on the HV side of the transformer must grade with the overcurrent
inverse time characteristic on the LV side which in turn must grade with the LV outgoing circuits. The overcurrent
function provides limited protection for internal transformer faults because sensitive settings and fast operation
times are usually not possible. Sensitive settings are not possible because the pickup should allow overloading of
the transformer when required. Fast operating times are not possible because of the grading required with respect
to downstream overcurrent relays. To allow fast operating times, phase instantaneous overcurrent functions with
low transient overreach are required.
P64x
Chapter 9 - Current Protection Functions
P64x-TM-EN-1.3
207
Summary of Contents for P642
Page 2: ......
Page 18: ...Contents P64x xvi P64x TM EN 1 3 ...
Page 24: ...Table of Figures P64x xxii P64x TM EN 1 3 ...
Page 25: ...CHAPTER 1 INTRODUCTION ...
Page 26: ...Chapter 1 Introduction P64x 2 P64x TM EN 1 3 ...
Page 36: ...Chapter 1 Introduction P64x 12 P64x TM EN 1 3 ...
Page 37: ...CHAPTER 2 SAFETY INFORMATION ...
Page 38: ...Chapter 2 Safety Information P64x 14 P64x TM EN 1 3 ...
Page 50: ...Chapter 2 Safety Information P64x 26 P64x TM EN 1 3 ...
Page 51: ...CHAPTER 3 HARDWARE DESIGN ...
Page 52: ...Chapter 3 Hardware Design P64x 28 P64x TM EN 1 3 ...
Page 87: ...CHAPTER 4 SOFTWARE DESIGN ...
Page 88: ...Chapter 4 Software Design P64x 64 P64x TM EN 1 3 ...
Page 98: ...Chapter 4 Software Design P64x 74 P64x TM EN 1 3 ...
Page 99: ...CHAPTER 5 CONFIGURATION ...
Page 100: ...Chapter 5 Configuration P64x 76 P64x TM EN 1 3 ...
Page 121: ...CHAPTER 6 TRANSFORMER DIFFERENTIAL PROTECTION ...
Page 122: ...Chapter 6 Transformer Differential Protection P64x 98 P64x TM EN 1 3 ...
Page 165: ...CHAPTER 7 TRANSFORMER CONDITION MONITORING ...
Page 166: ...Chapter 7 Transformer Condition Monitoring P64x 142 P64x TM EN 1 3 ...
Page 189: ...CHAPTER 8 RESTRICTED EARTH FAULT PROTECTION ...
Page 190: ...Chapter 8 Restricted Earth Fault Protection P64x 166 P64x TM EN 1 3 ...
Page 215: ...CHAPTER 9 CURRENT PROTECTION FUNCTIONS ...
Page 216: ...Chapter 9 Current Protection Functions P64x 192 P64x TM EN 1 3 ...
Page 249: ...CHAPTER 10 CB FAIL PROTECTION ...
Page 250: ...Chapter 10 CB Fail Protection P64x 226 P64x TM EN 1 3 ...
Page 259: ...CHAPTER 11 VOLTAGE PROTECTION FUNCTIONS ...
Page 260: ...Chapter 11 Voltage Protection Functions P64x 236 P64x TM EN 1 3 ...
Page 274: ...Chapter 11 Voltage Protection Functions P64x 250 P64x TM EN 1 3 ...
Page 275: ...CHAPTER 12 FREQUENCY PROTECTION FUNCTIONS ...
Page 276: ...Chapter 12 Frequency Protection Functions P64x 252 P64x TM EN 1 3 ...
Page 286: ...Chapter 12 Frequency Protection Functions P64x 262 P64x TM EN 1 3 ...
Page 287: ...CHAPTER 13 MONITORING AND CONTROL ...
Page 288: ...Chapter 13 Monitoring and Control P64x 264 P64x TM EN 1 3 ...
Page 306: ...Chapter 13 Monitoring and Control P64x 282 P64x TM EN 1 3 ...
Page 307: ...CHAPTER 14 SUPERVISION ...
Page 308: ...Chapter 14 Supervision P64x 284 P64x TM EN 1 3 ...
Page 322: ...Chapter 14 Supervision P64x 298 P64x TM EN 1 3 ...
Page 323: ...CHAPTER 15 DIGITAL I O AND PSL CONFIGURATION ...
Page 324: ...Chapter 15 Digital I O and PSL Configuration P64x 300 P64x TM EN 1 3 ...
Page 336: ...Chapter 15 Digital I O and PSL Configuration P64x 312 P64x TM EN 1 3 ...
Page 337: ...CHAPTER 16 COMMUNICATIONS ...
Page 338: ...Chapter 16 Communications P64x 314 P64x TM EN 1 3 ...
Page 397: ...CHAPTER 17 CYBER SECURITY ...
Page 398: ...Chapter 17 Cyber Security P64x 374 P64x TM EN 1 3 ...
Page 415: ...CHAPTER 18 INSTALLATION ...
Page 416: ...Chapter 18 Installation P64x 392 P64x TM EN 1 3 ...
Page 431: ...CHAPTER 19 COMMISSIONING INSTRUCTIONS ...
Page 432: ...Chapter 19 Commissioning Instructions P64x 408 P64x TM EN 1 3 ...
Page 460: ...Chapter 19 Commissioning Instructions P64x 436 P64x TM EN 1 3 ...
Page 461: ...CHAPTER 20 MAINTENANCE AND TROUBLESHOOTING ...
Page 462: ...Chapter 20 Maintenance and Troubleshooting P64x 438 P64x TM EN 1 3 ...
Page 477: ...CHAPTER 21 TECHNICAL SPECIFICATIONS ...
Page 478: ...Chapter 21 Technical Specifications P64x 454 P64x TM EN 1 3 ...
Page 507: ...APPENDIX A ORDERING OPTIONS ...
Page 508: ...Appendix A Ordering Options P64x P64x TM EN 1 3 ...
Page 512: ...Appendix A Ordering Options P64x A4 P64x TM EN 1 3 ...
Page 513: ...APPENDIX B SETTINGS AND SIGNALS ...
Page 515: ...APPENDIX C WIRING DIAGRAMS ...
Page 516: ...Appendix C Wiring Diagrams P64x P64x TM EN 1 3 ...
Page 590: ......
Page 591: ......