ABB RER620 Technical Manual page 558

Section 11
Requirements for measurement transformers
552
current and it does not trip with the maximum load current. The settings for all three stages
are as in the figure above.
For the application point of view, the suitable setting for instantaneous stage (50P-3) in this
example is 3 500 A (5.83 x I
by the current transformer selection formula is fulfilled and also the relay setting is
considerably below the F
selected much lower than 10 VA for economical reasons.
). For the CT characteristics point of view, the criteria given
2n
. In this application, the CT rated burden could have been
a
1MAC309294-MB F
RER620
Technical Manual