
The OST principle uses positive sequence impedances. The positive sequence impedance is calculated as Z
1
=
V
1
/I
1
, where V
1
and I
1
are the positive sequence voltage and current quantities derived from the measured phase
quantities. The concentric quadrilaterals are designated Zone 5 and Zone 6. Zone 5 encompasses possible system
fault impedances and sits within Zone 6. Because OST and Predictive OST quadrilaterals are based on positive
sequence impedances, all OST conditions are covered by a single measurement. Both quadrilaterals are
independent and have independent reach settings.
All four resistive blinders are parallel, using the common angle setting (
a
) that corresponds to the angle of the total
system impedance (Z
T
= Z
S
+ Z
L
+ Z
R
), where Z
S
and Z
R
are equivalent positive sequence impedances at the
sending and receiving ends and Z
L
positive sequence line impedance. The reactance lines are also parallel as
neither reactance line tilting nor esidual compensation is implemented.
In the figure, the purple solid impedance trajectory represents the locus for the non-recoverable power sawing,
known as a pole slip or Out Of Step condition. The dotted green impedance trajectory represents a recoverable
power swing.
4.2
OUT OF STEP PROTECTION OPERATAING PRINCIPLE
The Out of Step function has four different setting options, which are only visible if the PowerSwing Block is
enabled in the CONFIGURATION column:
●
Disabled
: Disables the Out of Step function.
●
Pred. OST
: Splits the system in advance. It minimizes the angle shift between two ends and aids stability
in the split areas.
●
OST
: Splits the system when an out of step condition is detected, which is when a pole slip occurs.
●
Pred. OST or OST
: Splits the system in advance or when an out of step condition is detected.
The Out-of-Step detection algorithm is based on the speed of the positive sequence impedance passing through
the characteristic. When the positive sequence impedance enters the outer quadrilateral (Zone 6) a timer is
started. The timer is stopped after the positive sequence impedance passes through the inner quadrilateral (zone
5). Let us call this time the zone 6 to zone 5 transition time.
If this time is less than 25 ms, the protection considers this to be a power system fault, not an Out-of-Step
condition. This 25 ms time is fixed and cannot be set. During a power system fault, the speed of change from a
load impedance to a fault impedance is fast, but the protection may operate slower for marginal faults close to a
zone boundary. This is particularly the case for high resistive faults inside the zone operating characteristic and
close to the Zone 5 boundary. The fixed time of 25 ms is implemented to provide sufficient time for a distance
element to operate and therefore to distinguish between a fault and an extremely fast power swing.
If the zone 6 to zone 5 transition time takes more than 25 ms but less than the set delta T time, this is treated as a
very fast power swing and the protection will trip if either the
Pred. OST Trip
or the
Pred. & OST Trip
options are selected and the Out-of-Step tripping time delay (Tost) has expired. The minimum delta T setting is 30
ms, allowing 5 ms margin with the fixed 25 ms timer.
If the zone 6 to zone 5 transition time takes longer than the set delta T time, it is considered as a slow power
swing. On entering Zone 5, the protection records the polarity of the resistive part of the positive sequence
impedance. From this state, two outcomes are possible:
●
If the resistive part of the positive sequence impedance leaves Zone 5 with the same polarity as previously
recorded on entering Zone 5, it is considered to be a recoverable swing. In this case, the protection does not
trip.
●
If, when exiting Zone 5, the resistive part of the positive sequence impedance has the opposite polarity to
that of the recorded polarity on entering Zone 5, an Out-of-Step condition is recognised. This is followed by
tripping if either
Pred. OST Trip
or
Pred. & OST Trip
is selected.
As the tripping mode for the detected Out-of-Step condition is always three-phase, the Pred. OST and OST DDB
signals are mapped to the three-phase tripping signal in the default programmable scheme logic.
Chapter 10 - Power Swing Functions
P446SV
242
P446SV-TM-EN-1
Summary of Contents for MiCOM P40 Agile
Page 2: ......
Page 24: ...Contents P446SV xxii P446SV TM EN 1 ...
Page 33: ...CHAPTER 1 INTRODUCTION ...
Page 34: ...Chapter 1 Introduction P446SV 2 P446SV TM EN 1 ...
Page 46: ...Chapter 1 Introduction P446SV 14 P446SV TM EN 1 ...
Page 47: ...CHAPTER 2 SAFETY INFORMATION ...
Page 48: ...Chapter 2 Safety Information P446SV 16 P446SV TM EN 1 ...
Page 60: ...Chapter 2 Safety Information P446SV 28 P446SV TM EN 1 ...
Page 61: ...CHAPTER 3 HARDWARE DESIGN ...
Page 62: ...Chapter 3 Hardware Design P446SV 30 P446SV TM EN 1 ...
Page 88: ...Chapter 3 Hardware Design P446SV 56 P446SV TM EN 1 ...
Page 89: ...CHAPTER 4 SOFTWARE DESIGN ...
Page 90: ...Chapter 4 Software Design P446SV 58 P446SV TM EN 1 ...
Page 101: ...CHAPTER 5 CONFIGURATION ...
Page 102: ...Chapter 5 Configuration P446SV 70 P446SV TM EN 1 ...
Page 124: ...Chapter 5 Configuration P446SV 92 P446SV TM EN 1 ...
Page 125: ...CHAPTER 6 SAMPLED VALUE OPERATION ...
Page 126: ...Chapter 6 Sampled Value Operation P446SV 94 P446SV TM EN 1 ...
Page 136: ...Chapter 6 Sampled Value Operation P446SV 104 P446SV TM EN 1 ...
Page 137: ...CHAPTER 7 DISTANCE PROTECTION ...
Page 138: ...Chapter 7 Distance Protection P446SV 106 P446SV TM EN 1 ...
Page 196: ...Chapter 7 Distance Protection P446SV 164 P446SV TM EN 1 ...
Page 197: ...CHAPTER 8 CARRIER AIDED SCHEMES ...
Page 198: ...Chapter 8 Carrier Aided Schemes P446SV 166 P446SV TM EN 1 ...
Page 240: ...Chapter 8 Carrier Aided Schemes P446SV 208 P446SV TM EN 1 ...
Page 241: ...CHAPTER 9 NON AIDED SCHEMES ...
Page 242: ...Chapter 9 Non Aided Schemes P446SV 210 P446SV TM EN 1 ...
Page 256: ...Chapter 9 Non Aided Schemes P446SV 224 P446SV TM EN 1 ...
Page 257: ...CHAPTER 10 POWER SWING FUNCTIONS ...
Page 258: ...Chapter 10 Power Swing Functions P446SV 226 P446SV TM EN 1 ...
Page 281: ...CHAPTER 11 AUTORECLOSE ...
Page 282: ...Chapter 11 Autoreclose P446SV 250 P446SV TM EN 1 ...
Page 376: ...Chapter 11 Autoreclose P446SV 344 P446SV TM EN 1 ...
Page 377: ...CHAPTER 12 CB FAIL PROTECTION ...
Page 378: ...Chapter 12 CB Fail Protection P446SV 346 P446SV TM EN 1 ...
Page 389: ...CHAPTER 13 CURRENT PROTECTION FUNCTIONS ...
Page 390: ...Chapter 13 Current Protection Functions P446SV 358 P446SV TM EN 1 ...
Page 416: ...Chapter 13 Current Protection Functions P446SV 384 P446SV TM EN 1 ...
Page 417: ...CHAPTER 14 VOLTAGE PROTECTION FUNCTIONS ...
Page 418: ...Chapter 14 Voltage Protection Functions P446SV 386 P446SV TM EN 1 ...
Page 431: ...CHAPTER 15 FREQUENCY PROTECTION FUNCTIONS ...
Page 432: ...Chapter 15 Frequency Protection Functions P446SV 400 P446SV TM EN 1 ...
Page 438: ...Chapter 15 Frequency Protection Functions P446SV 406 P446SV TM EN 1 ...
Page 439: ...CHAPTER 16 MONITORING AND CONTROL ...
Page 440: ...Chapter 16 Monitoring and Control P446SV 408 P446SV TM EN 1 ...
Page 476: ...Chapter 16 Monitoring and Control P446SV 444 P446SV TM EN 1 ...
Page 477: ...CHAPTER 17 SUPERVISION ...
Page 478: ...Chapter 17 Supervision P446SV 446 P446SV TM EN 1 ...
Page 490: ...Chapter 17 Supervision P446SV 458 P446SV TM EN 1 ...
Page 491: ...CHAPTER 18 DIGITAL I O AND PSL CONFIGURATION ...
Page 492: ...Chapter 18 Digital I O and PSL Configuration P446SV 460 P446SV TM EN 1 ...
Page 504: ...Chapter 18 Digital I O and PSL Configuration P446SV 472 P446SV TM EN 1 ...
Page 505: ...CHAPTER 19 FIBRE TELEPROTECTION ...
Page 506: ...Chapter 19 Fibre Teleprotection P446SV 474 P446SV TM EN 1 ...
Page 522: ...Chapter 19 Fibre Teleprotection P446SV 490 P446SV TM EN 1 ...
Page 523: ...CHAPTER 20 ELECTRICAL TELEPROTECTION ...
Page 524: ...Chapter 20 Electrical Teleprotection P446SV 492 P446SV TM EN 1 ...
Page 534: ...Chapter 20 Electrical Teleprotection P446SV 502 P446SV TM EN 1 ...
Page 535: ...CHAPTER 21 COMMUNICATIONS ...
Page 536: ...Chapter 21 Communications P446SV 504 P446SV TM EN 1 ...
Page 606: ...Chapter 21 Communications P446SV 574 P446SV TM EN 1 ...
Page 607: ...CHAPTER 22 CYBER SECURITY ...
Page 608: ...Chapter 22 Cyber Security P446SV 576 P446SV TM EN 1 ...
Page 625: ...CHAPTER 23 INSTALLATION ...
Page 626: ...Chapter 23 Installation P446SV 594 P446SV TM EN 1 ...
Page 637: ...CHAPTER 24 COMMISSIONING INSTRUCTIONS ...
Page 638: ...Chapter 24 Commissioning Instructions P446SV 606 P446SV TM EN 1 ...
Page 695: ...CHAPTER 25 MAINTENANCE AND TROUBLESHOOTING ...
Page 696: ...Chapter 25 Maintenance and Troubleshooting P446SV 664 P446SV TM EN 1 ...
Page 712: ...Chapter 25 Maintenance and Troubleshooting P446SV 680 P446SV TM EN 1 ...
Page 713: ...CHAPTER 26 TECHNICAL SPECIFICATIONS ...
Page 714: ...Chapter 26 Technical Specifications P446SV 682 P446SV TM EN 1 ...
Page 741: ...APPENDIX A ORDERING OPTIONS ...
Page 742: ...Appendix A Ordering Options P446SV P446SV TM EN 1 ...
Page 744: ...Appendix A Ordering Options P446SV A2 P446SV TM EN 1 ...
Page 745: ...APPENDIX B SETTINGS AND SIGNALS ...
Page 746: ...Appendix B Settings and Signals P446SV P446SV TM EN 1 ...
Page 954: ...Appendix B Settings and Signals P446SV B208 P446SV TM EN 1 ...
Page 955: ...APPENDIX C WIRING DIAGRAMS ...
Page 956: ...Appendix C Wiring Diagrams P446SV P446SV TM EN 1 ...
Page 960: ......
Page 961: ......