Research On Harmonic Resonance And Prevention Of Power System

The parameters of capacitor and inductor matching and system operation changes cause resonance occurs in power system. At the same time, along with the rapid development of modern power industry, non-linear equipment, especially power electronic technology, bring a lot of harmonic. Harmonic resonance and waveform distortion reduce power quality greatly, and pose a serious threat to the security of the system operation. As a result, the research on harmonic resonance is an important subject with theoretical significance and practical value.The Paper studied the steady-state harmonic resonance. It proposed a new method that analysis the harmonics impedance characteristic. It found the resonant point and amplifier region. It eliminated harmonic resonance and narrowed the amplifier region by using the method of serial reactor capacitor branch translation. Then, based on the calculation of voltage distortion rate and current distortion rate, we filtered the frequency harmonic that exceed standard of harmonic content. Finally, it proposed a design method of filter that consider various factors such as reactive power compensation and checking phase operation, it achieved good effect of harmonic management.In power system, single phase grounding fault frequently caused ferromagnetic resonance over-voltage of electromagnetic voltage transformer. This thesis established a simulation model of single phase grounding fault of center point ungrounded system by PSCAD. It presented a new method of judgment whether ferromagnetic resonance happen. This article used FFT to voltage waveform and obtained frequency spectrum, it expressly displayed the harmonic content of ferromagnetic resonance. Finally, the eliminating resonance method was grounding neutral point through arc suppression coil, it achieved a good effect.