Reserch On PT Ferroresonance Mechanism And Suppression Measures In 10kV Power System

In 10KV power system,there is a lot of electromagnetic voltage transformer(PT),which used to monitor neutral voltage,insulation levels,etc.Because of the nonlinear properties of transformer core excitation coil,some switching operations or ground fault disappears in the system,which might inspire ferromagnetic resonance over-voltage.Ferromagnetic resonance was caused by PT core saturation,and ferromagnetic resonance over-voltage was frequency in lOKv grid,and overvoltage had caused a very serious accident.In this paper,the mechanism of ferromagnetic resonance occurs and commonly used suppression measures are described,and ferromagnetic resonance parameters,characteristics and hazards are summarized.In lOkV power system,when the grid disturbance receive some three-phase voltage imbalance increases,transformer core may be saturated and then magnetizing inductance core decreases,when the inductance parameters match the system of capacitance,ferromagnetic resonance occurs.Ferromagnetic resonance for the power system,the establishment of the ATP-EMTP simulation and the model is based on a single-phase ground fault disappears for ferromagnetic resonance excitation conditions,by setting a model species to-ground capacitance and inductance parameters to match PT core of ferromagnetic resonance was simulated.Then a variety of existing harmonic elimination measures simulation were studied,and a variety of measures to suppress the effect of harmonic elimination of ferromagnetic resonance were analyzed and compared.Finally,a new harmonic elimination program was proposed:Parallel PT harmonic elimination,through simulation of the program on the grid resonance suppression effect,the program that avoids 4PT harmonic elimination method can not only quickly capacitive current in larger systems problem,but also overcome the problem of voltage harmonic elimination method of measurement error,which has great practical value.