Application Guide - NP900 Series
152 (504
)
A996A
Figure 3.2.13-79 Simplified function block diagram of the OV function.
3.2.13.1
M
EASURED INPUT VALUES
For the function block is used analog voltage measurement values. Function block utilizes
always peak-to-peak measurement from samples and the monitored magnitude is
fundamental frequency RMS values. -20 ms averaged value is used for the pre-fault data.
Table 3.2.13.1-104 Analogic magnitudes used by the OV function.
Signal
Description
Time base
U
L12
RMS
Fundamental RMS measurement of voltage U
L12
/V
5 ms
U
L23
RMS
Fundamental RMS measurement of voltage U
L23
/V
5 ms
U
L31
RMS
Fundamental RMS measurement of voltage U
L31
/V
5 ms
U
L1
RMS
Fundamental RMS measurement of voltage U
L1
/V
5 ms
U
L2
RMS
Fundamental RMS measurement of voltage U
L2
/V
5 ms
U
L3
RMS
Fundamental RMS measurement of voltage U
L3
/V
5 ms
Table 3.2.13.1-105 Measured magnitude selection setting.
Name
Description
Range
Step
Default
Measured magnitude Selection of P-P or
P-E voltages
0: P-P Voltages
1: P-E Voltages
-
0: P-P Voltages
Selection of the used AI channel is made with a setting parameter. In all possible input
channel variations pre-fault condition is presented with 20 ms averaged history value from
-20 ms of Start or Trip event.
