5.12
SEL-787 Relay
Instruction Manual
Date Code 20081022
Metering and Monitoring
Through-Fault Event Monitoring
Download the load rate profile data using the serial port
LDP
command
described in
LDP Command (Load Profile Report) on page 7.24
.
shows an example
LDP
serial port command response.
=>
LDP <Enter>
SEL-787 Date: 2008/01/17 Time: 18:07:05
TRNSFRMR RELAY Time Source: Internal
# DATE TIME IAW1_MAG IAW1_ANG IBW1_MAG IBW1_ANG ICW1_MAG ICW1_ANG
23 2008/01/14 16:16:40.992 0.099 0.000 0.225 -52.125 0.344 -108.435
22 2008/01/14 16:21:40.270 124.580 0.000 124.853 -119.627 123.668 120.426
21 2008/01/14 16:26:40.157 124.346 0.000 124.902 -119.358 123.626 120.711
20 2008/01/14 16:31:40.019 124.309 0.000 124.886 -119.598 123.973 120.577
19 2008/01/14 16:36:40.024 124.293 0.000 124.836 -119.361 123.403 120.631
18 2008/01/14 16:41:40.056 124.559 0.000 124.813 -119.709 123.970 120.493
17 2008/01/14 16:46:40.275 124.249 0.000 124.774 -119.646 123.907 120.574
16 2008/01/14 16:51:40.333 124.589 0.000 124.671 -119.569 123.603 120.483
15 2008/01/14 16:56:40.908 0.088 0.000 0.188 45.000 0.395 -26.565
14 2008/01/15 17:01:40.934 124.293 0.000 124.842 -119.504 123.485 120.619
13 2008/01/15 17:06:40.972 124.490 0.000 124.758 -119.463 123.546 120.518
12 2008/01/15 17:11:40.038 124.341 0.000 124.741 -119.297 123.424 120.779
11 2008/01/16 17:16:40.045 124.320 0.000 125.130 -119.517 123.630 120.623
10 2008/01/16 17:21:40.295 124.476 0.000 124.687 -119.537 123.518 120.455
9 2008/01/16 17:26:40.070 124.284 0.000 124.874 -119.413 123.649 120.818
8 2008/01/16 17:31:40.168 0.129 0.000 0.182 106.928 0.210 49.399
7 2008/01/17 17:36:40.215 124.313 0.000 125.154 -119.530 123.752 120.662
6 2008/01/17 17:41:40.803 124.383 0.000 124.992 -119.613 123.796 120.550
5 2008/01/17 17:46:40.282 124.446 0.000 124.799 -119.464 123.600 120.444
4 2008/01/17 17:51:40.077 124.432 0.000 124.710 -119.774 123.728 120.379
3 2008/01/17 17:56:40.114 124.288 0.000 125.274 -119.590 123.905 120.605
2 2008/01/17 18:01:41.047 124.392 0.000 124.730 -119.483 123.404 120.576
1 2008/01/17 18:06:41.020 0.210 0.000 0.099 -8.130 0.182 -57.529
=>
Figure 5.15
LDP Command Report
Through-Fault Event Monitoring
shows a fault that occurs outside the area of unit protection of the
transformer. Such through faults can last for several cycles, subjecting the
transformer windings to mechanical stress and the transformer winding
insulation to thermal stress. Monitor and document this through-fault activity
with the through-fault element in the SEL-787. The through-fault element also
calculates the cumulative mechanical stress on the transformer windings.
Figure 5.16
Transformer Bank Subjected to Through Fault
shows through-fault curves for Category IV transformers as
published in IEEE Standard C57.109-1993. These curves apply to
transformers that are covered by the IEEE standard or, in general, to
transformers that were built beginning in the early 1970s. For transformers
built prior to 1970, consult the manufacturer to obtain the transformer short-
circuit withstand capabilities.
Source
HV CT
HV
Breaker
Transformer
LV
Breaker
LV CT
Fault
Summary of Contents for SEL-787
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