6–60 345 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION CHAPTER 6: SETPOINTS
Phase timed overcurrent (51P)
The relay has two Phase Time Overcurrent elements per protection group. The settings of
this function are applied to each of the three phases to produce phase overcurrent trip or
pickup. There is no intentional “dead band” where the current is above the pickup level.
However the pickup accuracy is guaranteed within the current input accuracy of 3%
above the set PKP value. The TOC pickup flag is asserted when the current on any phase is
above the PKP value. The TOC trip flag is asserted if the element stays picked up for the
time defined by the selected inverse curve and the magnitude of the current. The element
drops from pickup without operating if the measured current drops below 97-99% of the
pickup value before the time for operation is reached. When Definite Time is selected, the
time for TOC operation is defined only by the TDM setting. The selection of Definite Time
has a base time delay of 0.1 s, multiplied by the selected TD multiplier. For example the
operating time for TOC set to Definite Time and a TDM set to 5 will result in 5*0.1 = 0.5 s
applying the time delay accuracy outlined under the Technical Specification, and adding
approximately 8 to 10 ms output relay time.
The following path is available using the keypad. For instructions on how to use the
keypad, please refer to Chapter 3 - Working with the Keypad.
PATH:
SETPOINTS > S3 PROTECTION > SETPOINT GROUP 1(2) > PHASE TOC 1(2)
PH TOC1(2) FUNCTION
Range: Disabled, Latched Alarm, Alarm, Trip
Default: Disabled
For details see Common setpoints
.
The output relays #1 “R1 TRIP” (and #2 “R2 TRIP”) will operate when the Trip setting is
selected, and the Phase TOC operates.
1.0 2.901 1.312 0.537 0.343 0.266 0.227 0.202 0.186 0.174 0.165
2.0 5.802 2.624 1.075 0.687 0.533 0.453 0.405 0.372 0.349 0.331
4.0 11.605 5.248 2.150 1.374 1.065 0.906 0.810 0.745 0.698 0.662
6.0 17.407 7.872 3.225 2.061 1.598 1.359 1.215 1.117 1.046 0.992
8.0 23.209 10.497 4.299 2.747 2.131 1.813 1.620 1.490 1.395 1.323
10.0 29.012 13.121 5.374 3.434 2.663 2.266 2.025 1.862 1.744 1.654
IAC Inverse
0.5 0.578 0.375 0.266 0.221 0.196 0.180 0.168 0.160 0.154 0.148
1.0 1.155 0.749 0.532 0.443 0.392 0.360 0.337 0.320 0.307 0.297
2.0 2.310 1.499 1.064 0.885 0.784 0.719 0.674 0.640 0.614 0.594
4.0 4.621 2.997 2.128 1.770 1.569 1.439 1.348 1.280 1.229 1.188
6.0 6.931 4.496 3.192 2.656 2.353 2.158 2.022 1.921 1.843 1.781
8.0 9.242 5.995 4.256 3.541 3.138 2.878 2.695 2.561 2.457 2.375
10.0 11.552 7.494 5.320 4.426 3.922 3.597 3.369 3.201 3.072 2.969
IAC Short Inverse
0.5 0.072 0.047 0.035 0.031 0.028 0.027 0.026 0.026 0.025 0.025
1.0 0.143 0.095 0.070 0.061 0.057 0.054 0.052 0.051 0.050 0.049
2.0 0.286 0.190 0.140 0.123 0.114 0.108 0.105 0.102 0.100 0.099
4.0 0.573 0.379 0.279 0.245 0.228 0.217 0.210 0.204 0.200 0.197
6.0 0.859 0.569 0.419 0.368 0.341 0.325 0.314 0.307 0.301 0.296
8.0 1.145 0.759 0.559 0.490 0.455 0.434 0.419 0.409 0.401 0.394
10.0 1.431 0.948 0.699 0.613 0.569 0.542 0.524 0.511 0.501 0.493
Multiplier (TDM)
1.5 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0
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