Functionality
34 USER MANUAL FPC 200 - 3/2017
Neutral voltage displacement - ANSI code 59N
Neutral voltage displacement protection is a function that detects residual overvoltage. It comprises of time-delayed
characteristics.
2.3.2.1 Functionality
Neutral voltage displacement protection is used as time
delayed protection. As voltage input this function can
use measured U
e
or calculated 3U
0
source. It picks up
when voltage from selected source exceed the selected
threshold. The function can be enabled or disabled
through corresponding menu.
Several voltage displacement protection instances with
different settings can run independently at the same
time.
The selection of pickup value, pickup delay as well as
drop-out ratio and drop-out delay helps the user to fine
tune the protection according to the project
specifications.
Neut. voltage displ.
COUNTERS
0
Enabled:
1A 1B 2A 2B
No
Pickup:
Pickup value: 0,75
Trip delay:
1,5s
0
Trip:
CONTROL SETTINGS
Pickup delay:
5ms
Drop-out delay:
0,2s
0,95 Drop-out ratio:
BLOCK SETTINGS
Input: none
Input voltage:
Sum3U
Figure 2.26: Neutral voltage displacement protection setting as
seen on HMI.
2.3.2.2 Measurements
The value of earth voltage can be chosen between direct
measurements U
e
or calculated measurement using
symmetrical components 3U
0
. Input value can be set in
parameters settings for each instance of protection
separately.
2.3.2.3 Delays
Function includes following delays explained in Chapter
2.1:
Pickup delay
Trip delay
Drop-out delay
2.3.2.4 Block settings
Pickup of any instance separately of protection can be
individually blocked by any user defined signal [2.6.5.].
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