Protection Functions; Phase Current Differential Protection; Fibre Teleprotection Transfer Times; Autoreclose And Check Synychronism - GE P4A Technical Manual

Chapter 22 - Technical Specifications
3

PROTECTION FUNCTIONS

3.1

PHASE CURRENT DIFFERENTIAL PROTECTION

Pick-up
Drop-off
IDMT characteristic shape
DT operation
Typical instantaneous operation with default settings,
back-to-back propagation delay included
up to 4 terminals
5 or 6 terminals
Reset time
Repeatability
Characteristic
Current transformer ratio compensation
High set characteristic setting
*with HSHB contact and direct fibre.
3.2

FIBRE TELEPROTECTION TRANSFER TIMES

The table below shows the minimum and maximum transfer time for InterMiCOM64 (IM64). The times are
measured from opto initialization (with no opto filtering) to relay standard output and include a small propagation
delay for back-back test (2.7 ms for 64 kbits/s and 3.2 ms for 56 kbits/s).
IDiff IM64 indicates InterMiCOM64 signals working in conjunction with the differential protection fibre optic
communications channel. IM64 indicates InterMiCOM64 signals working as a standalone feature.
Configuration
IM64 at 64 k
IM64 at 56 k
IDiff IM64 at 64 k
IDiff IM64 at 56 k
3.3

AUTORECLOSE AND CHECK SYNYCHRONISM

Timers
3.4

PHASE OVERCURRENT PROTECTION

IDMT pick-up
DT pick-up
Drop-off (IDMT and DT)
512
Accuracy
Formula +/- 10%
0.75 x Formula +/- 10%
+/- 5% or 40 ms, whichever is greater
+/- 2% or 20 ms, whichever is greater
<1 cycle*
<1.25 cycles*
<60 ms
+/- 2.5%
UK curves IEC 60255-3 – 1998
US curves IEEE C37.112 – 1996
No affect on accuracy
No affect on accuracy
Permissive op times (ms)
13 - 18
15 - 20
22 - 24
24 - 26
Accuracy
+/- 20 ms or 2%, whichever is greater
Accuracy
1.05 x Setting +/-5%
Setting +/-5%
0.98 x setting +/-5%
Direct op times (ms)
17 - 20
19 - 22
23 - 25
25 - 27
P54xMED-TM-EN-1
P54A/B/C/E