Smart Phone Based FDR
Nowadays, the functionalities of Wi-Fi connection, high computing ability and use-friendly UI make the smartphone a possible, appropriate, efficient and economic platform for frequency monitoring. One major challenge of implementing the Frequency Disturbance Recorder (FDR) functionalities with a smartphone is to ensure globally synchronized timestamps relying on the PPS signal from GPS. We develop a smartphone-based FDR that provides a measurement accuracy of 0.1 mHz. The time signal from the widely available cellular radio for time synchronization is harvested instead of GPS signal. The phasor data may be transmitted over any wireless network for system and/or saved locally on the mobile device by using NTP synchronized time as global timestamp for the phasor data. As a result, we do not rely on continuous PPS signal to ensure accurate phase angle measurement and data synchronization. The signal sampling hardware can easily be integrated onto any phone.
Fig.1 APP of smartphone based FDR