Research On Power Grid Harmonic Restraining Method In Xinglongtai District

Along with the extensive improvement of power electronic technology, more and more power electronic devices are applied on various fields. But power electronic devices and non-linear load are used widely, which makes a great deal of harmonic current and wattless current immitted power grid. They severely affect safe-running and natural use of power grid electric devices, and make power quality decrease. So power grid harmonic elimination has been turning into a main research problem in power electronic technology, power system, electrical automation, electrical engineering theory.Harmonic detection and harmonic analysis which is the given of the harmonic compensator and also is the core technology of harmonic compensation are important parts for resolving harmonic problems. Because of the characteristic such as nonlinear, randomicity, chorology and the complexity of influencing factor, it is very difficult to detect or analyse the harmonic accurately. This article mainly introduces several methods for measuring or analyzing the harmonic like band-stop filter method, band-pass frequency selection method, FFT transformation method, instantaneous space vector method base on instantaneous reactive power theory, wavelet transformation method, etc.According to the detection and analysis the harmonic, this article mainly discusses the method to restrain the harmonic, such as reducing the content of harmonic source, absorbing the harmonic current at harmonic source, improving the power-supply environment. This article uses several harmonic restraining devices like passive filtering, active passive filtering and mixed-filtering in practice.In the end, with the examples from practice, this article does research on the harmonic pollution of Xinglongtai District Guojia-line grid, analyzes the content of harmonic and the composing of the harmonic source. MATLAB model and simulation studies are used to build the model about the circuitry of Guojia-line grid. There are three projects including passive filtering, active passive filtering and mixed-filtering proposed in this article. According to the result of the simulation, the applicability and the effect of the restraining in every project are analysed. Different projects are taken from the content of the harmonic and different composing of the harmonic source. Perfect harmonic restraining results are achieved in this article. It has very important directive significance to the harmonic restraining.