Frequency

The frequency is continuously determined from the voltage curves of the grid. This is based on the change in the phase angle of a reference signal (typically voltage L1) over time. The calculation is performed using a phase locked loop (PLL). The PLL synchronizes itself to the fundamental of the measured voltage. The current frequency is calculated from the phase change. Short-term fluctuations are smoothed out by filtering.

The frequency is a central variable for synchronization, grid monitoring and other frequency-dependent evaluations.

The measured values are provided via the STcPowerMeasureFrequency structure.