Rockwell Automation 865 Differential Protection Relay - Manual (Page 5)

Table of Contents iii
865-UM001A-EN-P – July 2009
Inverse Time Operation ........................................................ 3-33
Stage Specific Inverse Delay .......................................... 3-33
Operation Modes ............................................................ 3-33
Local Panel Graph .......................................................... 3-33
Inverse Time Setting Error Signal .................................. 3-34
Limitation ....................................................................... 3-34
Standard Inverse Delays IEC, IEEE, IEEE2, RI ............ 3-35
IEC Inverse Time Operation .................................... 3-36
IEEE/ANSI Inverse Time Operation ....................... 3-38
IEEE2 Inverse Time Operation ............................... 3-42
RI and RXIDG type Inverse Time Operation .......... 3-43
Free Parametrisation using IEC, IEEE and IEEE2
Equations ................................................................. 3-45
Programmable Inverse Time Curves .............................. 3-46
Inverse Time Setting Error Signal .................................. 3-47
Limitations ..................................................................... 3-47
Chapter 4
Supporting Functions Event Log ................................................................................4-1
Event Enabling/Masking .................................................. 4-1
Event Buffer Overflow ..................................................... 4-2
Disturbance Recorder ............................................................. 4-2
Triggering the Recorder ................................................... 4-2
Reading Recordings ......................................................... 4-2
Number of Channels ........................................................ 4-3
Available Channels .......................................................... 4-3
Current Transformer Supervision ........................................... 4-5
Circuit Breaker Condition Monitoring ................................... 4-6
Breaker Curve and its Approximation ............................. 4-6
Setting Alarm Points ........................................................ 4-7
Clearing “Operations Left” Counters ............................... 4-8
Operation Counters to Monitor the Wearing .................... 4-8
Logarithmic Interpolation ................................................ 4-8
Example of the Logarithmic Interpolation ....................... 4-9
Example of Operation Counter Decrementing ................. 4-9
System Clock and Synchronization .......................................4-11
Adapting Auto Adjust .................................................... 4-11
Time Drift Correction Without External Sync ............... 4-11
System Clock Parameters ..................................................... 4-13
Running Hour Counter ......................................................... 4-14
Timers ................................................................................... 4-14
Combined Overcurrent Status ............................................... 4-16
Self-Supervision ................................................................... 4-17
Chapter 3
Protection Functions
(cont.)