Figure 3-8 Logic Diagram : Nps Phase Unbalance (46Nps) - Siemens 7SR105 Rho User Manual

3.1.4.1 Negative Phase Sequence
If negative phase sequence (NPS) protection is the selected method of phase unbalance protection then the NPS
component derived from the three phase input currents is used.
The operate equation for inverse time characteristic shown in
Gn 46 Element
Disabled
Enabled
Inhibit 46
I
A
I
B
I
C
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&
Mag.
NPS (I )
2
or
NPS
Figure 3-8 Logic Diagram : NPS Phase Unbalance (46NPS)
Figure 3-7
is implemented as:
1
t t
= ×
m
2
 I 
   
2
I
 
θ
Gn 46 Type = NPS
Gn 46 Setting
Gn 46 Characteristic
Gn 46 Time Mult
Gn 46 Delay (DTL)
Gn 46 Min Op Time
En
Pickup
Op.
7SR105 Rho Description of Operation
General Pickup
46
Chapter 1 Page 31 of 57