ABB REG316 4 Series - Functional Check; Recommended Settings for R F, Respectively U-Setting and T; Required Data

ABB Switzerland Ltd REG 316*4 1MRB520049-Uen / Rev. B
4-14
4.2.3.2.1. Required data
No special data are required in order to determine the settings
for the protection. Determining the settings by calculation is
somewhat difficult and therefore they are determined by meas-
urement.
4.2.3.2.2. Recommended settings for R
f
, respectively ‘U-Setting’ and t
Basically any value may be set for R
f
and the time delay t within
their available ranges.
Very sensitive settings are not recommended to prevent mal-
operation of the protection during fast load regulation on the
power system. This is especially the case in schemes which trip
the field switch and shut the machine down.
Recommendation:
· Stage 2: “Trip”
R
£ 2000 W
t ³ 1.5 s
· Stage 1: “Alarm”
R
£ 5000 W
t ³ 1.5 s.
Note that the difference voltage across the bridge is low for high
leakage resistances and high for low leakage resistances.
4.2.3.3. Functional check
The procedure for checking the function of the protection prior to
installation or connection is given in Section 4.2.3.5.3. Alterna-
tively a test circuit can be set up as shown in Fig. 4.7 and the
procedure followed according to Section 4.2.3.5.4.