Figure 12: Identification of demand, supply and power factor profile according to the phase angle factor (IEC
60375)
3.3.5
Symmetrical components
Voltage and current unbalances are evaluated on the basis of positive and negative sequence components of
fundamental harmonic.
Voltage unbalance:
unb
U
=
negative sequence component
positive sequence component
×
100%
Current unbalance:
unb
I
=
negative sequence component
positive sequence component
×
100%
Negative sequence current:
ϕnsl
3.3.6
Aggregation and Recording
Values are aggregated and stored in the archive in instrument memory according to the settings of the recording
interval. Aggregated (average) values are recorded by default for all selected parameters. Maximum/minimum
values can be separately selected to be recorded. This feature is off by default to save free space.
Aggregation of each interval starts at the beginning of the cycle (determined by RTC tick), following the
expiration of the previous time interval as required by the standards. If all the available memory capacity for
main archive is used than the archive creation stops or restarts according to the Main Archive configuration. If
’
Cyclic Recording
’ is not selected, the instrument stops recording until it is reconfigured (and thus erased) by
user or software. Otherwise the recording continues with the new measured values overwriting the oldest values
in memory (FIFO). The device contains the “latest” set of records, which corresponds to the memory capacity
of the actual device and configuration.
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