Harmonic And Impedance Research On PCC Based On Harmonic Power Flow

In recent years, with the development of power electronics technique and the majority of non-linear loads were used, more and more harmonics was injected into the network. The existence of harmonic made the system operation abnormal heavily. So, there is immediate significance to study the harmonics in power system.The research of harmonics produced by power system harmonic sources is necessary to carry out the research of power system harmonic. The existence of harmonic sources in power system is extensively, especially the power electronics apparatus. This paper discussed the harmonic sources and how they produce harmonic in detailed, such as generator, transformer, power electronics apparatus and others. The harmonic power flow is the most valid method to study power system harmonic. In order to calculate the harmonic power flow, the parameter model of the elements and loads in power system must be achieved. This paper deduced the harmonic parameter models of electrical transformers, generators, transmission lines and electrical loads in detail. The harmonic power flow algorithm, particularly the three-phase harmonic power flow algorithm of power system is studied based on these harmonic models. This paper presents a three-phase harmonic power flow algorithm using phase components and back-forward sweep method to solve the disconvergence when the three-phase transformer harmonic model was used. The example result presented the method was feasible and.The point of common coupling (PCC) is a bus which connects the customer and utility. The research of harmonics and its components at PCC is a valid way to distinguish the responsibility between customer and utility and to manage the harmonic producer. Some methods were proposed, but there still exist some questions, for example the method for analyzing the harmonic component at PCC. In this paper, the harmonic components at PCC were detailed analyzed, a new method and a new model were proposed to analyze the harmonic. In this paper, the harmonic energy at PCC was analyzed and distinguished the responsibility between customer and utility. The harmonic impedance is very important to harmonic power flow and analysis of harmonic at PCC. It is very difficult to measure the harmonic impedanceof a network or a load. This paper proposed the steady-state method, introduced the questions that might be occurred and how to solve them. This paper derived the measurement method of three-phase harmonic impedance. The study of the paper paves the way for deep study.