Toshiba GR-200-5 Instruction Manual

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6F2T0207 (0.01)GRE200 (5,6)- 553 -Power quality monitoring (PWRQTY)High order harmonics components will degrade a sinusoidal waveform and degrades the powerquality. It may reduce the loss of energy and mal-operations can be brought for the operationof protection relays occasionally. Since the high order harmonics components are uneasilyneglected in the power system, the protection relay should measure the harmonic order ifrequired; an alarm should be issued if high order harmonistic is observed critically.Power quality monitoring function (PWRQTY) can visualize high -order harmonicscomponents (up to 15th order) using the discrete Fourier transformation (DFT). The DFT canoperate 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 demandinformation called ‘total harmonic distortion (THD)’ and ‘Total demand distortion (TDD)’.The PWRQTY function also can monitor the phase-to-phase voltages (VAR). If the functionobserves sudden phenomena such as instantaneous voltage rise and drop or momentary powerfailure, the function can memory the information (time, period, and its maximum andminimum value) and send the reports for the upstream.Select and operate logics are embedding in the PWRQTY function, so that the user can clearthe recording memory at the remote through the IEC61850 communication. For the remotecontrol, the user should set On for setting [PWRQTY-EN].