Design And Simulation Of HVDC Transmission Converter Systems Based On The Inductive Filtering Transformer

Energy resource is unevenly distributed in our country, which is usually far away from the center of power load, so how to transmit the power in an economical and efficient way is the most concern of electric power industry. As a traditional transmission mode, the AC transmission which has nearly a hundred of years of history makes a great contribution to social modernization and energy saving. Along with the progress of the power electronic technology, the DC transmission has made great development and application all over the world. However, DC transmission system generates a lot of harmonics and reactive power accompanied by transmission of active power due to the inherent nonlinear characteristics of the power electronic device, which not only bring adverse effect to the DC transmission, but also threat the stability of the grid. So how to suppress the harmonics and compensate the reactive power plays a very important role in the efficient and safe operation of the DC transmission system. Although the presently used filtering methods in engineering practice have suppressed harmonics to some extent and reduced the adverse effect of the harmonics to the AC grid, it lacks the detailed analysis on the effect to the DC transmission. For this reason, the world is actively searching for a more efficient solution.Inductive filtering method’s technology, emerging as the times require is a new method of suppressing power harmonics. This new technology brings a brand-new solution to the filtering strategy of HVDC converter stations in power system, which suppresses harmonics just nearby where they generate. This paper is based on the inductive filtering method, and does a lot of relevant research about filtering and reactive compensation of the DC transmission. The main work is summarized as following:First, introducing the current situation and development tendency of HVDC system comprehensively, especially analyzing and summarizing the problem of traditional HVDC system. Second, the traditional technology of power filtering has been introduced and the novel converter transformer and its filtering system have been sketched out. Based on that, with the requirement of a practical DC transmission engineering, the system’s parameters of the DC transmission system have been calculated and checked by traditional filtering and the inductive filtering method respectively. These two types of DC transmission system have been simulated and studied in electromagnetic transient field based on the PSCAD/EMTDC, and the highlight is the analysis of the harmonic characteristic comparison between traditional and new filtering method. At last, according to the trait of the inductive filtering method, some matters related to the new technology are presented when implementing it in practical engineering. The results show that the new DC transmission system with a new filtering system proves a good performance of the harmonic suppression characteristics.