A new Phase Locked Loop Strategy for Power Quality Instruments Synchronisation

Power quality instrumentation requires the accurate fundamental frequency estimation and the signal synchronization, even in presence of disturbances. In the paper the authors present an innovative synchronization technique, based on a single phase software PLL. To evaluate how the synchronization technique is adversely affected by the application of stationary and transient disturbing influences, appropriate testing conditions have been developed, taking into account the requirements of the in-force standards. In the paper the proposed technique is described and PLL performances in presence of stationary and transient disturbances are presented