59N Neutral Voltage Displacement
Overview of Functions
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
th
voltage input by alternative configuration of
settings
Structure of the Function
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
th
voltage input measured voltage.
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.
5.23
5.23.1
5.23.2
Protection and Automation Functions
5.23 59N Neutral Voltage Displacement
Reyrolle 7SR5, Overcurrent Protection Device, Device Manual 313
C53000-G7040-C014-1, Edition 11.2019
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