Development and Implementation of Synchronized Phasor Measurements for Dynamic State Power System Monitoring and Fault Identification

Abstract

In real time the magnitude and phase angle of the voltage and current signals vary continuously. The measurement of magnitude and phase angles of these signals are very important for the visualization of real-time power systems pictorially and knowing dynamic power flow studies. This work presents the measurement of the voltage and current signal's magnitude and phase angles with time synchronization. The magnitude and phase angle are represented with a single quantity phasor. For the measurement of phasor values two different techniques are used, they are Recursive Discrete Fourier Transform (RDFT), and Non-Recursive Discrete Fourier Transform (NRDFT). With the RDFT the phasor (magnitude and phase angle) values are constant with time variation, with fixed load and constant supply. By varying the load or source the magnitude of the phasor is changed and the phase angle is constant. The values obtained from these results are used for the dynamic power flow calculation of the power system. With the NRDFT the phasor magnitude is constant the phase angle values are varying (rotating) with a speed of (ωt) and with a step of (1/N). The values obtained with this method are used for real-time power system visualization. The values obtained from the RDFT and NRDFT are time-stamped with GPS time. With GPS time stamping, the measurements are time synchronized, and real-time visualization of the power system is obtained.