AC Frequency measurement

Jayvie Gabriel Templonuevo
Jayvie Gabriel Templonuevo Altair Community Member
edited October 8 in Community Q&A

I am measuring the frequency deviation in a microgrid operating in islanded mode during load changes. Currently, I use a Phase-Locked Loop (PLL) block to measure the system's frequency. However, despite following the PLL Help instructions for calculations, I notice significant ripple in the frequency output (as shown in the attached image).

Are there alternative methods to measure the system's frequency through the voltage or current waveforms? If not, how can I reduce the sinusoidal ripple in the PLL output? I have already tried applying a Low Pass Filter (LPF), but while it attenuated the oscillations, it also dampens the frequency deviation (e.g., without the LPF, the minimum frequency is 49.2 Hz, but with the LPF, it is 49.3 Hz).

image

 

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Answers

  • VSiddhartha
    VSiddhartha
    Altair Employee
    edited October 8

    Hi Jayvie,

    Are you working on PSIM example schematic? (or) developed your own micro grid system?

    If schematic available, then it is easy to understand the problem and propose solution.

     

    Thank you,

    Vishwanatha Siddhartha

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