The Study On Detecting Methods Basic On The New Current Average Method

With the development of the power system, more and more power electronic equipments are used in practice. The using of non-linear load gives the power grid a lot of harmonics,and badly affects the quality of electricity and the safe run of power system. The harmonics source is random, dispersive, its quantity is huge and environment is complicated. Harmonics detection is the basis of harmonics problem, and is also the foundation to deal with the harm of harmonics. The harmonics detection methods based on current average method are discussed in this paper. And then, the design of the detecting device is presented, which using DSP and GPRS. This device not only can detect random harmonic current, but also can transfer informations. The work in this paper is contented as follows:â‘ The harmonics detection methods, the develepment of detecting harmonics devicea and the methods of communication are shortly introduced and discussed in this paper.â‘¡In this paper, a reformative current average method is presented and applied for random harmonic current detection with the ip-iq principle. The reformative method conquers the localization that the conventional current average method can only be used in the fundamental current detection in three-phase circuit. In addition, this method produces a faster dynamic response than conventional ip-iq principle using filters, so it has biggish practicality value. The method presented in this paper is easily realization, and it has a high precision. Analysis and simulation prove the correctness of the reformative method.â‘¢According to the new harmonic detection methods of this paper, the practical detection system is founded, with designing the circuits and programs, which tasks such as A/D transformation, capturing the cross-zero points of voltage, detecting harmonic current, transferring information and so on. The source programs of DSP are written out in C language, and are tested on experimental board successfully and all the tasks are finished perfectly as well.