TECHNICAL DESCRIPTION Kamstrup 162M/382M
5512-1040 GB/05.2012/Rev. C1
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Figure 9: Neutral fault measurement principle.
Figure 9 shows a situation without neutral fault and one with neutral fault. When the netraul fault is present the
load is asymmetric and the neutral fault voltage VN occurs.
The green vectors indicate the phase voltages on the grid. The yellow vectors indicate the phase voltages
measured by the meter.
The neutral fault is detected, when the following conditions are present:
Two of the phase voltages VL1, VL2 and VL3 must be above the threshold voltage VLHiTh.
One of the phase voltages VL1, VL2 and VL3 must be below the threshold voltage VLLoTh.
Condition 1 and 2 must be present in a time period longer than the period Time.
VLLoTh = 230V - VNTh
Figure 10: Neutral fault detection range.