Siemens 7SR12 Argus User Manual

7SR11 & 7SR12 Description Of Operation
©2017 Siemens Protection Devices Limited Chapter 1 Page 55 of 88
3.13 Voltage Protection: Negative Phase Sequence
Overvoltage (47) – 7SR12
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 A binary or virtual input.
47-n U/V Guarded Under voltage guard element.
Inhibit 47-
n
47-n Element
Enabled
Disabled
47-n
47-n Delay
&
c
47-n Hysteresis
>
47-n Setting
VL1
VL2
VL3
NPS
Filter
V2
General Pickup
Figure 3-28 Logic Diagram: NPS Overvoltage Protection (47)
3.14 Voltage Protection: Neutral Overvoltage (59N) – 7SR12
Two Neutral Overvoltage (or Neutral Voltage Displacement) elements are provided 59NIT & 59NDT.
The relay utilises fundamental voltage measurement values for this function. The element can use a direct
measurement 3Vo connection from the voltage transformer or calculate values from a phase to neutral
connections from the voltage transformer.
The 59NIT element can be configured to be either definite time lag (DTL) or inverse definite minimum time
(IDMT),
59NIT Setting sets the pick-up voltage level (3V0) for the element.
An inverse definite minimum time (IDMT) can be selected using 59NIT Char. A time multiplier is applied to the
characteristic curves using the 59NIT Time Mult setting (M):
Alternatively, a definite time lag delay (DTL) can be chosen using 59NITChar. When Delay (DTL) is selected the
time multiplier is not applied and the 59NIT Delay (DTL) setting is used instead.
An instantaneous or definite time delayed reset can be applied using the 59NIT Reset setting.
The 59NDT element has a DTL characteristic. 59NDT Setting sets the pick-up voltage (3V0) and 59NDT Delay
the follower time delay.
Operation of the neutral overvoltage elements can be inhibited from:
Inhibit 59NIT A binary or virtual input.
Inhibit59NDT A binary or virtual input.
[ ]
ms
1
M*1000
t
Vs
3Vo
op






−
=

Siemens 7SR12 Argus Specifications

General

Brand	Siemens
Model	7SR12 Argus
Category	Protection Device
Language	English