Research On Mechanism And Eliminstion Of Ferroresonance In Distribution Networks

Ferroresonance resonance over-voltage is the common internal over-voltage of distribution network, In order to monitor power generation and substation bus voltage on the ground, we usually connected in the bus on a voltage transformer. And we often connected the primary winding into the star and neutral grounding. At this moment, the excitation voltage transformer impedance and the system-to-ground capacitance come into being non-linear resonant circuit. As the loop parameters and the different conditions of external excitation, the may bring the possible frequency, frequency or high frequency ferromagnetic resonance. The over-voltage and over current of resonance affect the safe operation of the system seriously. Therefore it's important to fully understand the mechanism of ferromagnetic resonance and simulate ferromagnetic resonance over-voltage model.This paper aimed at 35kV and lOkV system, based on MATLAB Simulation platform, establishing electromagnetic voltage transformer model and ferroresonance model for 35kV and lOkV distribution network in Isolated Neutral System.During the simulation, simulation experiment was carried out for PT module based on MATLAB platform results are good. Besides, this paper discussed the actual line simplification during the simulation and ferresonance elimination. It shows that 4PT Wiring can Restrain ferresonance in a better way.Finally, this paper analyzed PT High-Voltage side fuse found in Shiqiaopu Station and Xinzao Station of Electric Power Bureau of Mianyang, the results are because of the low-frequency resonant ferromagnetic resonance frequency caused by over saturation current. In conclusion, this paper proposed the methods of ferresonance elimination and verified that 4PT wiring can suppress over-current and over-voltage well.