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

7SR105 Rho Description of Operation
©2018 Siemens Protection Devices Chapter 1 Page 31 of 57
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
Figure 3-7 is implemented as:
m
t
I
I
t ×








=
2
2
1
θ
Inhibit 46
46
&
I
A
I
B
I
C
Mag.
or
NPS
NPS (I
2
)
General Pickup
Pickup
Op.
Enabled
Disabled
Gn 46 Element
Gn 46 Type = NPS
Gn 46 Setting
Gn 46 Characteristic
Gn 46 Time Mult
Gn 46 Delay (DTL)
Gn 46 Min Op Time
En
Figure 3-8 Logic Diagram : NPS Phase Unbalance (46NPS)