Thermal Protection: Phase Unbalance (46); Figure 3-7 Inverse Time Characteristic For Unbalance Protection - Siemens 7SR17 Rho Manual

Chapter 1) 7SR17 Rho Description Of Operation
3.1.4

Thermal Protection: Phase Unbalance (46)

This provides separate protection for the conditions of phase unbalance, loss of phase and reverse phase
sequence. When enabled this feature can be programmed to operate either as a magnitude difference protection
or as a negative phase sequence (NPS) overcurrent protection.
Gn 46 Type Setting determines the method of phase unbalance protection to be used - either NPS or magnitude
difference.
Gn 46 Setting sets the pick-up level for the element.
Gn 46 Characteristic Setting allow the user to select the operate characteristic to either inverse or definite time
lag.
Gn 46 Time Mult Setting
Gn 46 Delay (DTL) Setting is used to define the minimum operate time for the protection characteristic.
Gn 46 Min Operate Time Setting
Operation of the negative phase sequence overcurrent elements can be inhibited from:
Inhibit 46
1.0x time
multiplier
0.3x time
multiplier
Figure 3-7
Page 34 of 78
A binary or virtual input
100.00
10.00
1.00
0.10
10
% Unbalance
Inverse Time Characteristic for Unbalance Protection
20% Unbalance Setting
30% Unbalance Setting
0.5sec
minimum
operate time
setting
100
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