Calculation of resonant modes for power supply systems and development of measures on higher harmonics filtering

This paper presents the calculation of non-stationary non-sinusoidal mode of the power supply system (PSS) under the condition of current resonance (parallel resonance). Evaluation of the need for higher harmonics (HH) filtering was carried out. To achieve this, measurements of the actual level of HH and other unified power quality indexes were conducted, and oscillograms of the network mode parameters and HH spectrum were constructed. The measurement of unified power quality indexes was carried out with certified and calibrated power quality analyzers Metrel 2792A. These instruments satisfy the effective world standards on power quality and other reference documentation. Resonance frequencies where resonance modes emergence is possible were determined by calculation. Maximum overvoltage ratios for different points of the examined PSS were also determined.