5.12
SEL-787 Relay Instruction Manual Date Code 20150130
Metering and Monitoring
Small Signal Cutoff for Metering
Small Signal Cutoff for Metering
The relay applies a threshold to the secondary voltage and current magnitude
metering quantities to force a reading to zero when the measurement is near
zero. The threshold for fundamental metering current values is 0.01 • INOM A
(secondary) and for voltage values is 0.1 V (secondary). The threshold for
RMS metering current values is 0.03 • INOM A (secondary) and for voltage
values is 0.3 V (secondary).
Load Profiling
The SEL-787 includes a load profiling function. The relay automatically
records selected quantities into nonvolatile memory every 5, 10, 15, 30, or
60 minutes, depending on the LDAR load profile report setting (see Load
Profile Settings on page 4.110). Choose which analog quantities you want to
monitor from the analog quantities listed in Appendix K: Analog Quantities.
Set these quantities into the LDLIST load profile list report setting.
The relay memory can hold data for 6500 time-stamped entries. For example,
if you chose to monitor 10 values at a rate of every 15 minutes, you could
store 66 days worth of data.
Download the load rate profile data using the serial port LDP command
described in LDP Command (Load Profile Report) on page 7.29. Figure 5.15
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
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