
Figure. 5.4.8 - 204. Generator islanding.
As can be seen in the example above, only phase-to-phase voltages L1-L2 and L3-L1 have been
reduced, while voltage L2-L3 remains the same. This means that the problem occured in phase L1
of the network. The voltage level is not reduced to zero, nor is the voltage in any phase is totally lost.
The phases without the fault condition remain normal with the same value. On the other hand,
the frequency can sag as can be seen in the figure above.
The
Δα setting parameter controls the pick-up of the vector jump function. This defines the minimum
allowed rapid measured voltage angle change before action from the function. The function constantly
calculates the ratio between the Δα
set
and the measured magnitude (Δα
m
) for each of the selected
voltages. The function's stage trip signal lasts for 20 ms and automatically resets after that time has
passed. The setting value is common for all measured amplitudes.
Figure. 5.4.8 - 205. Vector jump from the relay's point of view.
Table. 5.4.8 - 212. Pick-up settings.
Name
Description
Range
Step
Default
Available stages
Defines if alarm is included with trip or not.
0: Trip
1: Trip and alarm
-
0: Trip
A
AQ
Q-F213
-F213
Instruction manual
Version: 2.04
325