Basler BE1-CDS220, Instruction Manual

Page: 73 / 476

BE1-CDS220 Protection and Control 4-7
Load Current
as % of S0-51 <pickup>
0
90 80 70 60 50 40 30 20 10 10 0
40
30
20
10
100
90
80
70
60
50
120
110
140
130
150
TIME
(MINUTES)
3
0
5
2
0
5
SP-GROUP3=5,90,5,75,51P
SP-GROUP2=30,75,20,70,51P
SG3
SG2
SG1
SG0
SGC
D2837-23
05-05-04
Figure 4-6. Automatic Operation Based on Load Change
This function can also be used to automatically change the active setting group for cold load pickup
conditions. If the switch to threshold for a group is set to 0%, the function will switch to that group when
there is no current flow for the time delay period indicating that the breaker is open or the circuit source is
out of service. The threshold for this is 10% nominal rating of the relay current input.
Figure 4-7 shows how the active setting group follows the load current and time delay settings for Setting
Group 1. Note that the AUTO input must be at a TRUE (1) logic state in order to allow the automatic logic
to operate. When the breaker opens, the load current falls to zero at time = 15 minutes. After 10 minutes,
Setting Group 1 becomes active and the setting group change output pulses TRUE. When the breaker is
closed at time = 40 minutes, load current increases to approximately 90 percent of pickup. As the load
current decreases to 50 percent of pickup, the Setting Group 1 return timer begins timing. After ten
minutes, Setting Group 1 output goes FALSE, the setting group returns to Setting Group 0 and the setting
group change output pulses TRUE.
When the switch-to criteria is met for more than one setting group at a time, the function will use the
numerically higher of the enabled settings groups. If the switch-to time delay setting is set to 0 for a
setting group, automatic control for that group is disabled. If the return time delay setting is set to 0 for a
setting group, automatic return for that group is disabled and the relay will remain in that setting group
until returned manually of by logic override control.