Influence of commutations of network elements on harmonic voltage level

The paper presents results of the research into the influence of commutations of HV network elements on harmonic mode. Harmonic voltage measurements at commutations in the network show that the electric network has a great influence on their levels. Harmonic voltage levels at commutations can both decrease and increase to values dangerous for equipment. The studies show that preliminary calculations of harmonic modes in the network with the aim of estimation of possible voltage levels should be made before commutation. New electric networks should be planned with account for provision of electricity quality when harmonics take place.