I want to design a 3 phase meter which provides following basic functions:
- Harmonic calculation
- Voltage dip monitoring
- Voltage swell monitoring
As I know, if the device needs harmonic calculation, the metering library with FFT should be used.
But to implement the voltage dip monitoring and swell monitoring function, the meter has to calculate the Urms
every 1/2 period, for 50 Hz grid, every 10 ms the Urms must be calculated. If I choose metering library with FFT, it must call METERLIBFFT_CalcMain first and this function take much time. If I call it every 10 ms, I am afraid the meter performance will reduce a lot.
Or I can use two metering library FFT and Filter at the same time, using Filter library to calculate Urms every 10 ms and FFT library to calculate harmonic every 20 ms (50 Hz).
Is there someone can tell me how I can solve this problem?