Identifying Different Types Of Electrical Power Systems - ABB ACS880-07 Hardware Manual

Identifying different types of electrical power systems


To identify the electrical power system type, find out the supply transformer connection. If
that is not possible, measure these voltages at the distribution board before you connect
power to the drive:
1. input voltage line to line (U
2. input voltage line 1 to ground (U
3. input voltage line 2 to ground (U
4. input voltage line 3 to ground (U
The line-to-ground voltages in relation to the line-to-line voltage of the electrical power
system types are shown below.
U U
L-L L1-G
X 0.58·X
X 1.0·X
X 0.5·X
X Varying level
versus time
)
L-L
)
L1-G
)
L2-G
).
L3-G
U U
L2-G L3-G
0.58·X 0.58·X
1.0·X 0
0.5·X 0.57·X
Varying level Varying level
versus time versus time
Electrical installation 103
Electrical power system type
Symmetrically grounded TN system (TN-S
system)
Corner-grounded delta system
(nonsymmetrical)
Midpoint-grounded delta system
(nonsymmetrical)
IT systems (ungrounded or high-resistance-
grounded [>30 ohms]) nonsymmetrical