GSC60
EN - 123
12.11. VERIFICATION OF VOLTAGE DROP ON MAIN LINES
Measurement voltage drop as a result of current flow through a main line or a part of it can
be very important if it is necessary:
Verify the capability of an existing main line to supply a load
Dimension a new installation
Search for possible causes of troubles on devices, loads, etc.. connected to a main line
Purpose of the test
Measure the maximum percentage value of voltage drop between two points of a main
line
Parts of the system to be checked
The test includes two sequential impedance measurements in the initial point of main
power line (typically downstream to a protection device) and in the final point of the same
line.
Allowable values
The instruments compares the calculated value of V% maximum voltage drop to the set
limit value (according to applicable guidelines) according to the following relationship:
where:
Z2 = End point impedance of the main line being tested
Z1 = Initial point impedance (Offset) of the main line being tested (Z2 > Z1)
INOM =
Nominal current of protection device of the main line being tested
V
NOM =
Phase-Neutral or Phase-PE nominal voltage of the main line being tested
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