抄録
Harmonics have existed in power systems for many years. Nowadays, power systems have experienced an increase in level of harmonic currents and voltages on their electrical delivery systems due to the rapid growth of power electronic devices in industry, the presence of products based on electronic component in enterprise, institutions, shops, residence and transport systems etc. The harmonic effect on power system equipment such as capacitor failure or transformer and neutral conductor overheating, has become one of the major power quality problems to be solved in the near future. To decrease harmonic distortion, the method such as passive filtering and active filtering are used to mitigate local harmonic currents and prevent them from influencing the main supply system. The reliable design of a passive filter requires a correct knowledge of the system harmonic impedance and its variations throughout the day to avoid creating a resonance condition, which could destabilize a power system. Active filters also require a good knowledge of the system harmonic impedance to ensure stable controller operation and also can be used in the generation of the filter reference currents. A technique that can estimate the system harmonic impedance from a Point of Common Coupling (PCC) could prove extremely useful information in many areas of power quality analysis. In this paper, we present the estimation of system harmonic impedance from PCC using complex Independent Component Analysis (ICA). The numerical simulations show that the proposed method can estimate the system harmonic impedance even in the condition that the load harmonic impedance is changing in mixing process.
