2 Connecting the current injection
The right choice measurement points, zero sequence voltage and measurement the
injected current when current injection used described detail the next chapter. should possible change the amplitude the injected current can ad-
just the grid losses different switching states. The losses are relatively small small
grids there little damping.5 kVA) instead
Use 2. The injection frequencies should not contain any components. The current injection must have
as little impact possible the zero sequence voltage because its absolute value
is used criterion detect earth faults.
0 Immune crosstalk the load
0 Immune measurement errors when measured the open delta winding
Additional requirements for regulation with current injection
Based the resonance curve and the normal grid operating characteristics, there are a
few additional requirements for current injection.
13.
Connection Notes
Supply voltage (230 AC, L1-N) Fused internally with fuse
CAUTION: not use circuit breaker!
Use isolating transformer 2. This why it's important inject lower current
especially the resonance point than further away from the resonance point
2.
1.5 mm
2
cable
UNE Measurement zero sequence voltage
Ideal voltage transformer that not measuring the
same magnetic circuit the power auxiliary winding.
Only four connections are needed retrofit current injection.5 mm
2
COM3 connection REG-DP/ REG-
DPA
4-wire RS-485 connection
Use shielded and twisted 2x2 core cable
Small signal line!
.Page 186 Commissioning current injection
We take care it.
Separate voltage transformer the P-coil
External voltage transformer
Measurement open delta winding the busbar
PAW
On the power auxiliary winding
Use connection cable that least 2
