UNIPOWER
UP-2210R/P Hardware installation and configuration manual
22
4.4.5
3 phase with 4 wire measurement with 3 CT’s and 2 PT’s
Figure 14
The above wiring diagram is used for three-phase measurement in in public distribution networks
with 3 CT´s and 2 PT’s. The voltage channels of the unit are connected to PT’s (normally 63 V AC
secondary to earth), for supplying line-to-line voltages, and current channels are connected to CT´s
(normally 1 - 5 A AC secondary).
Always
protect the voltage inputs with a suitable fuse in each
conductor on the secondary side of the PT. The connection for this type of measurement is as
follows:
Channel:
Measured object:
Channel:
Measured object:
U1
=
L1 PT+
I1+
=
L1 CT+
U2
=
L1 PT-, L3 PT-
I1-
=
L1 CT-
U3
=
L3 PT+
I2+
=
L2 CT+
Ref =
L1 PT-, L3 PT-
I2-
=
L2 CT-
I3+
=
L3 CT+
I3-
=
L3 CT-
