Analysis of resonance modes at harmonic frequencies in high-voltage networks

Abstract

Resonant  modes  in  electric  networks  occur  due  to the   presence   of   capacitive   and   inductive   elements   which compensate each other. Resonant circuits can occur on harmonic frequencies  (further  referred  to  as  harmonics).  If  the  networks have  consumers  of  electric  power  having  equipment  with  non-linear   current-voltage   characteristics   that   consumes   a   non-sinusoidal current, then the harmonics of currents and voltages in the  resonant  circuits  sharply  increase.  Harmonics  create  energy losses   in   electrical   equipment,   which   causes   its   additional heating,  leads  to  a  reduction  in  service  life  and,  as  a  result, additional   economic   damage.   Passive   filters   and   capacitors, which  are  used  to  compensate  reactive  power,  are  especially vulnerable in such cases.  Resonant  nodes  of  electrical  network  and  resonant  harmonics can  be  determined  by  calculating  the  frequency  responses  of  the input   impedances   or   admittances   of   the   nodes   for   various network  configurations  and  loads.  The  experience  of  studying harmonic  modes  in  electric  networks  allowed  us  to  develop  a methodical     approach     and     HARMONICSsoftware     for determining resonant nodes and resonant harmonics. The article provides methodical approach and some results of the research on resonant modes on the harmonics in the high-voltage networks in Eastern Siberia.