Power Quality Logger
Methods of Logging
37
Current Logging
The maximum values of the currents (L1 or A, L2 or B, L3 or C, and N) are
measured, and the interval value of the current is calculated using the mean
value over the RMS values of the interval defined in PQ Log.
Logging Function A
If a 3-phase current sensor is connected, the neutral current is calculated on a
sample basis from the phase currents. If a 3-phase+N sensor is detected, you
can select between logging and calculating the neutral current in PQ Log.
Ipeak
The peak values of the current (samples, not RMS values) are averaged in the
PQ Log software over the predefined measuring interval.
Note
Short peak values do not contribute much to the average value, and so
I
max
can be higher than I
peak
.
Crest Factor (CF)
The crest factor (CF) of the currents (L1 or A, L2 or B, L3 or C, and N) is the
ratio of current peak value divided by current RMS value, and is averaged over
the interval length defined in PQ Log. For sinusoidal signals: CF = 1.41, and
for square waves: CF = 1.00
Power
The power values (L1 or A, L2 or B, L3 or C and N) are averaged over the
interval length, and the maximum value of each is recorded.
The response time can be set to 1 second or 1 minute, and is independent of the
response time for voltage and current.
In logging function P, the active power, apparent power, and reactive power of
the phases and total power of all three phases is calculated.
Logging function A also calculates the distorting power D of the phases, and
D
total
.
