Micom P634 - Overfluxing Protection (Function Group V;F); Enabling or Disabling Overfluxing Protection; Conditioning the Measured Value

3.28 Overfluxing Protection (Function Group V/f)
The overfluxing protection function will detect an inadmissibly high induction B in
the iron core of transformers which may have been caused either by a voltage
increase and/or a frequency decrease.
3.28.1 Enabling or Disabling Overfluxing Protection
The overfluxing protection function can be enabled or disabled using setting
parameters. Moreover, enabling can be carried out separately for each
parameter subset.
64Z5191A
Parameter
set 1
set 2
set 3
set 4
V/f:
Enable PSx
081 210
082 210
083 210
084 210
V/f:
Enabled
[ 041 229 ]
V/f:
Enable PSx
[ * ]
1
0
0: No
1: Yes
0
0: No
1: Yes
V/f:
General enable USER
[ 019 097 ]
1
Fig. 3-141: Enabling or disabling overfluxing protection
3.28.2 Conditioning the Measured Value
The overfluxing protection function will evaluate the voltage to frequency (V/f)
ratio referred to nominal values. This ratio is proportional to the induction in the
iron core of a transformer. The overfluxing measurement is not enabled unless
the voltage and frequency values are within limits for admissible values.
64Z5193B
V/f:
Excitation V/f p.u.
[ 004 220 ]
V/f:
Enable meas.
460 569
MAIN:
Nominal frequ. fnom
[ 010 030 ]
V
V/f
> 0.5 fnom
< 1.5 fnom
> 0.5 Vnom
Fig. 3-142: Conditioning of measured value
P634
3 Operation
3-190 P634/EN M/R-42-A // P634‑311‑653