4.4 Connection alternatives
In the electric grid there are multiple configurations of instrument transformers (PT= Potential
Transformer, CT= Current Transformer). The UP-2210 meters support all standard 1-phase and 3-
phase connections. The meter is configured using PQ Online, where all the common connections
methods with their respective wiring diagrams available and a graphical explanation. Here it is also
possible to set the transformer ratios as constants.
4.4.1 1-phase measurement with direct voltage and one CT (Line-to-neutral voltage)
Figure 10
The above wiring diagram is used for single-phase measurement in low voltage networks. The
voltage channel of the unit is connected directly to the public distribution networks for measuring
line-to-neutral voltage (230 V) and therefore do not require an instrument transformer (PT).
However, the current channel is connected to existing instrument transformer, allowing the
measurement of high currents, e.g. directly from the secondary side of a power transformer. Always
protect the voltage inputs with a suitable fuse in each conductor (red conductor). The connection for
this type of measurement is as follows:
Channel: Measured object: Channel: Measured object:
U1 = L1 I1+ = L1 CT+
Ref = (Neutral) I1- = L1 CT-
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