46 - Current Unbalance Protection - Eaton EDR-5000 Nstallation, Operation And Maintenance Manual

EDR-5000 IM02602007E

46 - Current Unbalance Protection

Elements:
46[1] ,46[2]
This is the 46 device Current Unbalance setting, which works similar to the 47 device Voltage Unbalance setting. The
positive and negative sequence currents are calculated from the 3-phase currents. The Threshold setting defines a
minimum operating current magnitude of either I1 or I2 for the 46 function to operate, which ensures that the relay has a
solid basis for initiating a current unbalance trip. The » %(I2/I1)« setting is the unbalance trip pickup setting. It is
defined by the ratio of negative sequence current to positive sequence current » %(I2/I1)« for ABC rotation and » %
(I1/I2)« for ACB rotation. The device will automatically select the correct ratio based on the Phase Sequence setting in
the System Configuration group described above.
This function requires positive or negative sequence current magnitude above the threshold setting and the percentage
current unbalance above the » %(I2/I1)« setting before allowing a current unbalance trip. Therefore, both the threshold
and percent settings must be met for the specified Delay time setting before the relay initiates a trip for current
unbalance.
All elements are identically structured.
www.eaton.com 544