UMG 103-CBM
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10.4 Control of the power measurement
Short circuit all current transformer outputs except
one and check the power values displayed in the
GridVis software.
·The device must only measure power in the
phase with the current transformer input that is
not short-circuited.
·If this is not the case, check the connection of
the measured voltage and measured current.
If the amount of active power is correct, but the
sign of the active power is negative, this can have
two causes:
1. The connections S1(k) and S2(l) on the current
transformer are reversed.
2. Active energy is returned to the grid.
10.5 Checking measurement
Correctly connected voltage and current mea-
surement inputs result in correctly calculated
individual and summation power readings dis-
played in the GridVis software.
10.6 Checking individual power
If a current transformer is assigned to the wrong
phase, the corresponding power is measured
and displayed incorrectly.
The phase conductor and current transformer
are correctly assigned on the device if there is no
voltage between the phase conductor and the
associated current transformer (primary).
To ensure that a phase conductor at the voltage
measurement input is assigned to the correct
current transformer for the power measure-
ment, the respective current transformer can be
short-circuited on the secondary side. The ap-
parent power displayed in the GridVis software
must then be zero for this phase.
If the apparent power is measured correctly, but
the active power has a negative ("-") sign, then
the current transformer terminals are reversed or
power is being delivered to the electric utility.
10.7 Checking summation power
If all voltages, currents and powers for the re-
spective phase conductors are correctly mea-
sured, the summation powers measured by the
device are also correct. To confirm, compare
the summation powers displayed in the GridVis
software with the work of the active and reactive
power meters located in the feeder.
Summary of Contents for UMG 103-CBM
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