Neutral Voltage Displacement; Overview Of Functions; Structure Of The Function - Siemens 7SR51 Device Manual

5.23 59N Neutral Voltage Displacement

Overview of Functions

5.23.1
The function Neutral Voltage Displacement protection is used to:
•
Monitor for voltage displacement of the neutral point which should not normally be present in a
balanced 3 phase system. The neutral voltage is calculated from the 3 phase voltage inputs
•
Monitor for unbalance in the phase supply voltages of a 3 phase system
•
Identify abnormal system conditions which result in voltage unbalance in a 3 phase system
•
Monitor single phase voltage applied to the separate 4
settings

Structure of the Function

5.23.2
The neutral voltage displacement function elements have group dependent settings. These settings can be
different in each settings group – group numbers (Gn) 1 to 4.
This function corresponds to the logical nodes A59NITPTOV* and A59NDTPTOV* in IEC 61850.
The neutral voltage displacement protection function is used in devices with VT inputs voltage measurement
and is applied to the calculated sum of the VT1/2/3 inputs. Alternatively the function can be configured to
operate from the 4
There is 1 definite-time overvoltage protection element and 1 inverse-time overvoltage protection element.
The inverse-time element can be selected to a definite-time characteristic to provide a total of 2 DTL voltage
elements or a user definable inverse characteristic.
This protection function operates on the fundamental frequency component evaluated from processing of the
measured voltage samples.
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual
C53000-G7040-C014-1, Edition 11.2019
th voltage input measured voltage.
Protection and Automation Functions
5.23 59N Neutral Voltage Displacement
th voltage input by alternative configuration of
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