Basler BE1-CDS220, Instruction Manual

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BE1-CDS220 Testing And Maintenance 13-13
starting the test. The equations provide a convenient starting balance point at two times tap.
Do this for each setting group.
Step 4-3. Check that the starting (balanced) test current at two times tap is not above the maximum
continuous current rating of the relay. If it is, adjust both starting test currents downward until
both are below this level. Use the same adjustment factor on both currents such that they
remain balanced.
MIN PU
slope
1 2 3 4
1
2
y
1MI
y
1AI
y
1MD
y
1AD
y
1MD
= I1 decreasing with maximum restraint
y
1MI
= I1 increasing with maximum restraint
y
1AD
= I1 decreasing with average restraint
y
1AI
= I1 increasing with average restraint
Condition Restraint
Min PU?
Trip If Min PU Trip If Slope
I1 = I2
Decrease I1
I1 = I2
Increase I1
I1 = I2
Decrease I1
I1 = I2
Increase I1
Maximum
Maximum
Average
I2<min pu/slope
I1 = I2/(1 - slope)
I2<min pu(1/slope + 1/2)
Average I2<min pu(1/slope - 1/2)
I1 = I2*(1 - slope)
I2<min pu(1/slope - 1)
I1 = I2(1 - (2*slope/(2+slope)))
I1 = I2(1 + (2*slope/(2-slope)))
I1 = I2 - min pu
I1 = I2 + min pu
I1 = I2 + min pu
I1 = I2 - min pu
Ir
Iop
D2857-09.vsd
10-08-99
CDS Restraint Characteristic
Iop = |I1 - I2|
Ir = max(|I1|,|I2|) for max restraint
Ir = (|I1|+|I2|)/2 for average restraint
Figure 13-3. Test Currents for Restrained Trip Test