Basler BE1-50/51B-229, Instruction Manual

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4-2 BE1-50/51B-229 Installation 9252000892 Rev A
Figure 4-2. DC Connections
SETTING THE RELAY
Before placing the relay in service, the relay should be configured with the desired settings. Changing
pickup current settings while the relay is in service may cause tripping.
The four switches of SW3 must be adjusted for the desired operation before the relay is installed in the
case. Refer to Section 2,
Controls and Indicators for the location of SW3 and the operating characteristics
controlled by the four switches of SW3.
Application Coordination Example
In the following example of a typical application coordination scheme, a BE1-50/51B-229 relay is
providing primary protection for a radial distribution feeder. An electromechanical overcurrent relay with
extremely inverse timing provides protection for the transformer and bus. To improve coordination with
the electromechanical relay, the BE1-50/51B-229 relay, with integrating reset characteristic, has the time
characteristic curve E (extremely inverse) selected (SW3-3 open or off) and the time dial set at 2.0. The
feeder reclosing relay is set for two reclose attempts at 3 and 15 seconds after the initial trip. If a
permanent fault occurs (magnitude of 10 times pickup), calculate the feeder breaker trip time for each of
the three operations. Refer to Appendix A,
Time Overcurrent Curves for the characteristic curve
constants.
From the time characteristic curve equation:
seconds 209 . 0 028 . 0 2 02758 . 0
) 1 10 (
2 7624 . 7
) (
0938 . 2
= + × +
−
×
=
+ +
−
=
Trip Trip
N
Trip
T T
K BD
C M
AD
T