Time domain harmonic state estimation in unbalanced power networks based on optimal number of meters and the principle of half‐wave symmetry

Abstract

This paper proposes a time domain methodology for harmonic state estimation (HSE) in power systems. The proposed methodology is formulated to analyse the unbalanced operation of three-phase power systems including nonlinear loads. It takes into account the optimal number of measuring devices and exploits the property of half-wave symmetry in voltage and current waveforms to significantly reduce the computational effort of the solution process. The results obtained are in closely agreement with the actual response obtained from the time domain power system simulation performed with the SimPowerSystems toolbox of Simulink®. Hence, the proposed methodology can adequately assess the harmonic state in unbalanced power systems. The results show a considerable reduction in the instrumentation resources and time processing needed for HSE in nonlinear power networks.

Physics-Aware Sparse Harmonic State Estimation in Power Distribution Systems

“…Although there is a rich literature on the study of HSE at power transmission networks [1], [2], developing HSE methods at power distribution networks requires addressing its own unique issues. For a radial or weakly-meshed power distribution system, numerous harmonic measurement devices are needed to make the system fully-observable.…”

A novel iterative observer approach for real‐time harmonic estimation in power distribution networks

“…However, it cannot be applied to assess harmonic voltages at the resonance frequencies. In [20], a time domain method for HSE is proposed in unbalanced three-phase power systems including non-linear loads. The optimal number of involved devices and the property of half-wave symmetry in voltage and current waveforms are considered in this method to reduce the computational burden.…”

Practical Approaches to Assessment of Harmonics Along Radial Distribution Feeders

“…More recent publication considered time-varying harmonics in the estimation [8]. It was also shown in [9,10] that the time domain harmonic state estimation can be performed by applying new techniques and by utilising the advancement in computing hardware to reduce computational time.…”