ABB SACE Tmax XT5 Operation And Maintenance Manual page 54

OV2 Protection
t
U16
t16
Phase sequence The Phase Sequence protection trips when the sequence of line-to-line voltages is not aligned with the
VU Protection
t
U14
t14
52 | © 2019 ABB | 1SDH002039A1002 - ECN000093027 - Rev. A
Function
OV2 protection functions in the same way as OV protection: the protection sends a TRIP command if one or
more line-to-line voltages detected by the unit exceed threshold U16 for longer than t16.
OV2
To check and simulate the trip times in relation to all the parameters, please consult:
• summary table of the protections with the operating characteristics (page 80)
• the graph with trip curve (page 89)
Parameters
V
Parameter Description
Activates/deactivates the protection and its availability in the parameters
Enable
menu
Activates/deactivates transmission of the open command: if disabled, the
Trip Enable
alarm and exceedance of protection time are only managed as information
Establishes the value that activates the protection.
Threshold
The value is given as both absolute value (Volts) and relative value (Un) and
U16
can be set within the range: 1 Un to 1.5 Un in 0.001 Un steps
This is the trip time of the protection; the value is given in seconds and can
Time t16
be set within a range: 0.05 s to 120 s, in 0.01 s steps
Limitations and additional functions
The block functions can also be accessed by means of the service connector (via Ekip Connect) or by
connection to the system bus (page 75).
sequence set by the user.
The required sequence can be set in the Settings menu and the protection activated in the Advanced menu
(page 33 and page 31).
Function
The protection trips if the line-to-line voltages read by the unit are unbalanced; the protection sends a TRIP
command if the detected unbalance exceeds threshold U14 for longer than t14.
VU
The protection excludes itself if the maximum value of the line-to-line voltage is less than 0.3 Un
To check and simulate the trip times in relation to all the parameters, please consult:
• summary table of the protections with the operating characteristics (page 80)
• the graph with trip curve (page 89)
Parameters
V
Parameter Description
Activates/deactivates the protection and its availability in the parameters
Enable
menu
Activates/deactivates transmission of the open command: if disabled, the
Trip Enable
alarm and exceedance of protection time are only managed as information
Establishes the unbalance value that trips the protection.
Unbalance is expressed in percentage value and is calculated in the
following way: % Unba = 100 x (Δmax U
Threshold I14 steps.
This is the trip time of the protection; the value is given in seconds and can
Time t14
be set within a range: 0.5 s to 60 s, in 0.5 s steps
Limitations and additional functions
The block functions can also be accessed by means of the service connector (via Ekip Connect) or by
connection to the system bus (page 75).
NOTE: Δmax U : maximum deviation among the three voltages
mi
calculated by comparing each line-to-line voltage with the mean value;
U : mean value of the line-to-line voltages
mi
) / U in range: 2% to 90% in 1%
mi mi
Protections | 2 - Voltage protections
ABB | SACE Tmax XT
Default
OFF
OFF
1,05 Un
5 s
Default
OFF
OFF
50 %
5 s