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6F2T0207 (0.01)
Power quality monitoring (PWRQTY)
High order harmonics components will degrade a sinusoidal waveform and degrades the power
quality. It may reduce the loss of energy and mal-operations can be brought for the operation
of protection relays occasionally. Since the high order harmonics components are uneasily
neglected in the power system, the protection relay should measure the harmonic order if
required; an alarm should be issued if high order harmonistic is observed critically.
Power quality monitoring function (PWRQTY) can visualize high -order harmonics
components (up to 15
order) using the discrete Fourier transformation (DFT). The DFT can
th
operate for voltage and current entering at respective VCT terminals (channels).
The PWRQTY function examines the percentage of the harmonic distortion about waveform
(HHD). If the percentage is over the thresholds, the function can report them as demand
information called 'total harmonic distortion (THD)' and 'Total demand distortion (TDD)'.
The PWRQTY function also can monitor the phase-to-phase voltages (VAR). If the function
observes sudden phenomena such as instantaneous voltage rise and drop or momentary power
failure, the function can memory the information (time, period, and its maximum and
minimum value) and send the reports for the upstream.
Select and operate logics are embedding in the PWRQTY function, so that the user can clear
the recording memory at the remote through the IEC61850 communication. For the remote
control, the user should set On for setting [PWRQTY-EN].
GRE200 (5,6)
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