Figure 3-9 Logic Diagram: Phase Difference Phase Unbalance (46Pd) - Siemens 7SR105 Rho User Manual

3.1.4.2 Magnitude Difference Protection
If magnitude difference protection is selected as the method of phase unbalance protection the relay calculates
the magnitude difference relative to the thermal overload setting as follows:
Percentage
The operate equation for inverse time characteristic shown in
t =

 

Gn 46 Element
Disabled
Enabled
Inhibit 46
I
A
I
B
I
C
Figure 3-9
©2018 Siemens Protection Devices
I
Unbalance = Δ
I
θ
1
× t
m
2
I 
 
∆
I

θ
&
Mag.
Magnitude difference (IΔ)
or
NPS
Logic Diagram: Phase Difference Phase Unbalance (46PD)
× 100 %
Figure 3-7
is implemented as:
Gn 46 Type = Mag. Diff.
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 32 of 57