Voltage Protection: Negative Phase Sequence Overvoltage (47Nps); Figure 3-23 Logic Diagram: Under/Over Voltage Elements (27/59); Figure 3-24 Logic Diagram: Nps Overvoltage Protection (47) - Siemens 7SR10 Argus Series Manual

27/59-n
Enabled
Disabled
Inhibit 27/59-n
27/59-n VTS Inhibit
Yes
VT Fail
27/59 U/V Guarded
Yes
27/59 U/V Guard
Setting
<
<
<
Voltage
Input
Mode
VL1
PH-PH
VL2
Or
PH-N
VL3

Figure 3-23 Logic Diagram: Under/Over Voltage Elements (27/59)

3.4.10

Voltage Protection: Negative Phase Sequence Overvoltage (47NPS)

Negative phase sequence (NPS) voltage (V2) is a measure of the quantity of unbalanced voltage in the system.
The relay derives the NPS voltage from the three input voltages (VL1, VL2 and VL3).
Two elements are provided 47-1 & 47-2.
Voltage elements can be blocked if all phase voltages fall below the 47 U/V Guard setting.
47-n Setting sets the pick-up voltage level for the element.
The 47-n Hysteresis setting allows the user to vary the pick-up/drop-off ratio for the element.
An output is given after elapse of the 47-n Delay setting.
Operation of the negative phase sequence voltage elements can be inhibited from:
Inhibit 47-n
47-n U/V Guarded
47-n Element
Enabled
Disabled
Inhibit 47-n
VL1
VL2
VL3

Figure 3-24 Logic Diagram: NPS Overvoltage Protection (47)

©2018 Siemens Protection Devices Limited
&
&
&
27/59-n Operation
&
27/59-n Setting
27/59-n Hysteresis
c
A binary or virtual input.
Under voltage guard element.
47-n Setting
&
47-n Hysteresis
c
>
V2
NPS
Filter
> <
or
27/59-n O/P Phases
> < Any (≥1)
or
All (&)
> <
or
47-n Delay
7SR10 Description of Operation
General Pickup
27/59-n Delay
27/59-n
General Pickup
47-n
Chapter 1 Page 45 of 77