Enhancing Phasor Estimations in Power Systems Under Transient Conditions Using State Observers

Synchrophasor measurements are used as a tool to obtain information from an electrical network to make control decisions. The electrical grid is susceptible to many changes due to faults, lightning discharges, switching surges, transformer energization, back-to-back switching of capacitor banks, and so on. Hence, the phasor takes different shapes under several operating conditions of the electrical grid. Therefore, phasor estimation should consider changes in the waveform. In this article, a proposed methodology based on deterministic state observers is presented, where transients and modulation changes in the analyzed signals are considered during phasor measurement. This approach aims to provide competitive estimations using a simplified algorithm compared to Kalman phasor estimation techniques. To evaluate the proposed technique, the requirements of standard IEC/IEEE 60255-118-1 for protection relay applications and analytic measurements are studied.