Pf Control Relay
Posted 09 December 2006 - 11:24 AM
Hi !! I have a question regarding power factor control relay. As you know these relays can sense the power factor and switch on or switch off the capacitor banks to achieve required power factor. This relay gets current input ( may be through CTs ) and voltage input ( may be through PTs ). My questions is: In orer to calculate the system PF and control capacitor banks accordingly, does the MAGNITUDE of the current signal and voltage signal is of any importance or the relay will ignore the actual values and just see what is the phase angle between current and voltage?
Posted 09 December 2006 - 11:37 PM
If the power factor relay measures displacement power factor only, then the magnitudes of the voltage and current waveforms are not important. If the power factor relay measures true power factor (displacement plus distortion) then the amplitude and waveform shape are important.
Controlling capacitor banks can only affect displacement power factor, so many such relays measure displacement power factor only.
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