The Study Of Harmonic Source Separation At Point Of Common Coupling

Recent years, the development of power electric technology makes the pollution of harmonic in power system becoming more and more serious. In order to ensure the safety and economy of power system, we must restrict harmonics content in power system. Although the standards to control and restrict power hannonic of varies countries had been executed more than 10 years ago, the separation of hannonic sources at point of common coupling has not been effectively achieved because of the varies harmonic sources of power system, thus those standards have not yet been executed effectively.This paper first discusses and compares some harmonic source separation methods. The advantages and disadvantages of each method are illustrated. Based on analyzing user loads running characteristic and power system topology structure, this paper presents a new harmonic source separation method that is on-line search zero iterative method. Based on Thevenin theorem and Norton theorem, this method will be implemented by dividing a harmonic nonlinear circuit into Thevenin - Norton stacking linear circuits. During the process of on-line user load being launched into and removed, initialization background harmonic voltage will be calculated, using parameters of harmonic which measured as its current from zero to great value. And then using iterative analysis, the harmonic contents of power system and user load are calculated. At the process of user load running, there will be four cases that are the user just being launched into and removed, the user having launched into and removed, other user being launched into and removed linear load and other user being launched into and removed nonlinear load. Aimed at linear user load and nonlinear user load, using Simulink software simulated this method. Software simulation analysis shows that this method can completely achieve harmonic source separation in time on-line in the process of harmonic detecting. And it solves problem puzzling us to carry out harmonic standards. At last, this paper design hardware flat roof for harmonic separation. Front extremity input setting using Microcontroller Unit for core, implements harmonic data acquiring. Each front extremity use RS-485 bus implementing data communication with end extremity computer.