ABB RELION 620 Series Technical Manual page 670

Section 4
Protection functions
4.5.6.6
4.5.6.7
Table 623: NSPTOV Group settings (Basic)
Parameter
Start value
Operate delay time
Table 624: NSPTOV Non group settings (Basic)
Parameter
Operation
664
separately. Alternatively, the protection can be implemented with the NSPTOV
function, monitoring the voltage unbalance of the busbar.
If the machines have an unbalance protection of their own, the NSPTOV operation can
be applied as a backup protection or it can be used as an alarm. The latter can be
applied when it is not required to trip loads tolerating voltage unbalance better than the
rotating machines.
If there is a considerable degree of voltage unbalance in the network, the rotating
machines should not be connected to the network at all. This logic can be implemented
by inhibiting the closure of the circuit breaker if the NSPTOV operation has started.
This scheme also prevents connecting the machine to the network if the phase
sequence of the network is not correct.
An appropriate value for the setting parameter Voltage start value is approximately 3
percent of U . A suitable value for the setting parameter Operate delay time depends
n
on the application. If the NSPTOV operation is used as backup protection, the operate
time should be set in accordance with the operate time of NSPTOC used as main
protection. If the NSPTOV operation is used as main protection, the operate time
should be approximately one second.
Signals
Table 621: NSPTOV Input signals
Name
U
2
BLOCK
Table 622: NSPTOV Output signals
Name
OPERATE
START
Settings
Values (Range) Unit
0.010...1.000 xUn
40...120000 ms
Values (Range) Unit
1=on
5=off
Type Default Description
SIGNAL 0 Negative phase sequence voltage
BOOLEAN 0=False Block signal for activating the blocking mode
Type Description
BOOLEAN Operate
BOOLEAN Start
Step Default
0.001 0.030
1 40
Step Default
1=on
1MRS757644 F
Description
Start value
Operate delay time
Description
Operation Off / On
Technical Manual
620 series