Inverse Time Overfluxing - ABB REG316 4 Series Operating Instructions Manual

REG 316*4 1MRB520049-Uen / Rev. F
3.5.21. Inverse time overfluxing (U/f-Inv)
A. Application
Protection of generators and power transformers against ex-
cessive flux, especially in heavily loaded non-laminated metal
parts, and the associated excessive heating of the unit.
B. Features
· evaluation of the voltage/frequency ratio
· single-phase measurement
· inverse time delay according to U/f ratio
· determination of frequency from the complex voltage vector
· insensitive to DC components
· insensitive to harmonics
· delay determined by integrating function response
· input of delay table facilitates matching the operating charac-
teristic to a specific machine according to IEEE Guideline
C 37.91-1985.
· adjustable rate of counting backwards when the overfluxing
disappears.
C. Inputs and outputs
I. C.t./v.t. inputs:
·
II. Binary inputs:
·
III. Binary outputs:
·
·
IV. Measurements:
·
·
voltage
blocking
pick-up
tripping
voltage/frequency
frequency.
ABB Switzerland Ltd
3-205