High Precision Frequency Estimation Using Internet-Based Phasor Measurement Unit

This paper presents a measurement technique suited for real-time transfer, monitoring and processing of state variables in power distribution networks, in terms of synchronized phasors. The proposed technique, different from commercial phasor measurement units (PMUs), is based on general purpose data acquisition hardware and uses network time protocol (NTP) for accurate time-stamping of the measurements. A least square approximation scheme for accurate frequency estimation is proposed, and with this scheme, it has been proved that the range of frequency with zero estimation error increases with the increase in number of re-samplings.