Development of measures to eliminate resonant phenomena at higher harmonic frequencies on power line of 35 kV

One of the problems to ensure the quality of electricity and reliability of the network is significant deviation of the voltage curve from sinusoidal in some active electricity transmission lines of the energy system of the Irkutsk region. The purpose of the research is to develop organizational and technical measures to eliminate resonance phenomena at higher harmonics that occur in the active 35 kV electrical line connected to a traction power substation. The object of the research is non-sinusoidal mode of the 35 kV electric power transmission line connected to the medium voltage winding of the three-winding traction transformer. The authors have used technological research methods of calculation using an equivalent circuit of the existing linear circuit of an electrical power system with a traction substation. The software “Calculation program of non-symmetric and non-sinusoidal modes of the electric power system” and Microsoft Excel are used for the research. The authors have developed a 110–35–10 kV “Consumer 1 – Consumer 2 – Consumer 3” model using the software “Calculation program of non-symmetric and non-sinusoidal modes of the electric power system”. The calculation results are processed using Microsoft Excel. Non-sinusoidal electrical modes of the equivalent circuit of the electrical power system and the power transmission lines are calculated. Calculation of non-sinusoidal modes of a 35 kV line is carried out to show the distribution of higher harmonic voltages along the line. It is established that the quality indicators of electricity in terms of non-sinusoidal voltages in most nodes of the 35 kV power transmission line do not comply with GOST 32144-2013. Calculation and analysis of non-symmetric and non-sinusoidal modes of the network have shown resonance voltage increase along the line on the odd harmonics frequencies and elimination of resonance factor when installing the compensation reactor at the beginning of the 35 kV line. Based on the calculation results, the diagrams of harmonics power-voltage curve from 3 to 39 are compiled. Based on the results obtained, the authors have proposed technical measures such as installation of a compensation reactor at the beginning of the electrical power system line to prevent resonance factor to improve the electrical power quality in terms of voltage unsinusoidality in the consumers busbars connected to the 35 kV line. The proposed measures will improve the electrical power quality in busbars of consumers and satisfy the requirements of GOST 32144-2013.