1 The basics current injection
All the known processes are based the fact that zero sequence voltage created ei-
ther the natural unbalance the grid injecting current.
0 Currents can occur the secondary side for 500 power auxiliary wind-
ing.
There are situations, however, which this simplification longer allowed.
0 The process used calculate the grid parameters described Chapter 2.
The CIF algorithm (Control Injecting Frequencies) suppresses the component that
is caused the crosstalk from the load the zero sequence voltage.2. Two frequencies that
are unequal are injected into the zero sequence system estimate the grid pa-
rameters.
YU
BC
UNE
BL
YW
IU
ICI f1,f2 U1N_50 Hz
Figure 116: Simplified equivalent circuit for current injection
.
13.5.
General
0 not necessary, but possible, inject current and move the P-coil the same
time (the resonance curve calculated and not determined moving the P-coil). Commissioning current injection
Once the REG-DP/ REG-DPA has been commissioned, additional steps must taken to
commission CI.
Current injection features:
0 Two frequencies are used calculate the grid parameters
0 Switches off reduces the current injection, when the coil moves
0 Fast calculation; takes place within filter cycle (240 ms)
0 Works very symmetrical grids
0 Calculation results immune unbalance and crosstalk from the positive
sequence system the zero sequence system
0 Cyclical current injection for the constant monitoring changes the grid
13. The cross-section the power supply line must laid out accordingly. For exam-
ple, industrial grids that are very symmetrical but show significant load fluctuations. Note that the calculation time
can take anywhere from seconds minutes. The general
assumption that the grid situation the crosstalk behaviour the load the zero se-
quence voltage will not change during the calculation time.Page 184 Commissioning current injection
We take care it. The easiest way commission current injection work through the
steps the sequence the chapters they are discussed in
