Comparison between different power system frequency measurement methods for converter applications providing ancillary services

For improvement of power system stability, a variety of control strategies has been developed for converter-based loads and generators, that regulate the power consumption or generation dependent on the grid frequency. For unsymmetrical and transient grid conditions the effectiveness of these control strategies is highly dependent on the performance of the frequency measurement. This paper compares six standard grid synchronization techniques and an alternative method, based on voltage waveform period duration measurement. All methods are implemented either on a real-time system or as a circuit board and tested with a programmable AC voltage source. Measurement results are presented.