ABB ACH580-04, Руководство по оборудованию

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The table below shows the line-to-ground voltages in relation to the line-to-line voltage for
each grounding system.
Electrical power system type U
L3-G
U
L2-G
U
L1-G
U
L-L
Symmetrically grounded TN system (TN-S sys-
tem)
0.58·X 0.58·X 0.58·X X
Corner-grounded delta system (nonsymmetrical) 0 1.0·X 1.0·X X
Midpoint-grounded delta system (nonsymmetrical) 0.5·X 0.5·X 0.866·X X
IT systems (ungrounded or high-resistance-
grounded [>30 ohms]) nonsymmetrical Varying level
versus time
Varying level
versus time
Varying level
versus time
X
TT system (the protective earth connection for
the consumer is provided by a local earth elec-
trode, and there is another independently installed
at the generator)
Varying level
versus time
Varying level
versus time
Varying level
versus time
X
When you can connect the EMC filter and ground-to-phase
varistor: TN-S, IT, corner-grounded delta and
mid-point-grounded delta systems
Symmetrically grounded TN systems (TN-S systems)
You can connect VAR wire.
PE
L2
L3
L1
N
Corner-grounded delta systems
You can connect VAR wire.
PE
L3
L2
L1
Midpoint-grounded delta systems
232 Connecting EMC filter and ground-to-phase varistor – North America