Figure 3-8 Logic Diagram : Nps Phase Unbalance (46Nps) - Siemens 7SR17 Rho Manual

Chapter 1) 7SR17 Rho Description Of Operation
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:
1
t t
m
2
I
2
I
Figure 3-8 Logic Diagram : NPS Phase Unbalance (46NPS)
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