Lightweight Power Quality Monitoring Based on Improved Least Squares State Estimation

In order to realize the lightweight configuration of Power Quality Monitors (PQM), an improved weighted least squares state estimation method is proposed, and the PQM configured with the monitoring reach area analysis method is used to realize the harmonic voltage monitoring. The method realizes nodal voltage sag and harmonic voltage observation with the configuration scheme of less PQM. Firstly, based on the voltage sag value at the monitoring point when the fault occurs, the monitoring reach area of voltage sag is established to realize the configuration of voltage sag PQM. Secondly, according to the accuracy difference of measured data, the weight factors of state estimation of data with different precision are set. Finally, combined with the measured values of harmonic voltage, active power and reactive power, the improved weighted least squares method is used to estimate the harmonic state and realize the observable analysis of harmonic voltage. The proposed method is simulated and verified by the IEEE 14-bus system. The results show that the proposed method can realize the observable analysis of voltage sag and harmonic voltage based on limited measuring devices, and realize the lightweight configuration of PQM.