Application Guide - NP900 Series
165 (504
)
A996A
in phase L1 in the network. The voltage level is not reduced to zero or either the voltage in
any phase is totally lost. Phases without fault condition normally remain with the same
value. On the other hand, the frequency can sag as it can be seen in the figure below.
Pick-up of the VJP function alarm/trip is controlled by
Δα
setting parameter, which defines
the minimum allowed rapid measured voltage angle change before action from the
function. The function constantly calculates the ratio in between of the
Δα
set and
measured magnitude (
Δα
m) per all selected voltages. VJP stage trip signal lasts for 20
milliseconds and resets automatically after the time has passed. The setting value is
common for all measured amplitudes those are used.
Figure 3.2.15.2-84 Vector jump in the relay point of view.
Table 3.2.15.2-114 Pick-up characteristics setting
Name
Description
Range
Step
Default
Δα
Pick-up
setting
0.05 … 30.00 deg
0.01 deg
5 deg
U Block
setting
Block setting.
If set to zero
blocking is not
in use.
Operation
explained in
the next
chapter.
0.00 … 100.00 % Un
0.01 % Un
10 % Un
The pick-up activation of the function is not directly equal to start –or trip signal generation
of the function. Start signal is allowed if blocking condition is not active.
