Harmonic Analysis Of Multi-feed Transmission System Based On Modulation Iterative Analysis

With the continuous development of power transmission methods,the construction of a strong and smart grid with coordinated development of the UHV power grid at all levels of the grid is an inevitable requirement in the new era.While building large-scale long-distance transmission,the traditional single-feed HVDC transmission can no longer meet the requirements.When developing a new multi-infeed transmission method,it is particularly critical to analyze and study the harmonics generated by it.Based on the modulation theory and the iterative algorithm framework,this paper analyzes the advantages of the modulation iterative algorithm in harmonic analysis of multi-infeed transmission systems.Modulation theory describes the nonlinear behavior of the AC side and DC side of the converter using a switching function.The iterative algorithm takes into account the interaction between harmonics and makes the calculation more accurate by iterative iteration.It is a new attempt to apply the modulation iteration algorithm formed by their fusion to the harmonic analysis of a multi-infeed transmission system.The main research work done in this paper is as follows:1.The composition of AC side harmonics and DC side harmonics of the converter station is analyzed.Based on the existing modulation theory and iterative harmonic analysis method,the harmonic resonance analysis method is used to analyze the multi-infeed transmission system harmonics.The feasibility of the wave problem.Comparing the existing harmonic analysis algorithm with the modulation iterative harmonic analysis method,it shows that the modulation iterative harmonic analysis method has obvious advantages in the application of harmonics in multi-infeed transmission systems.2.A multi-infeed transmission system simulation model was established during steady-state operation,and the AC system,DC system components,and inverter model were studied.A dual-input bipolar 12-pulse ±800kv transmission system was simulated using the electromagnetic simulation software PSCAD/EMTDC,and the related harmonic data was further studied and analyzed.3.The modulation and iterative harmonic analysis method was applied to the multi-infeed transmission system for analysis and calculation,and compared with the traditional fast Fourier decomposition simulation results,it was verified that the modulation iterative harmonic analysis method was applied to harmonic analysis of multi-infeed transmission systems.Feasibility.At the same time,the research on the input configuration of the AC system and the DC system filter is carried out,which has certain reference value for the design of the filter device of the multi-infeed transmission system.In this paper,the principle of modulation iterative harmonic analysis method is studied theoretically.From the perspective of practice,the modulation iterative harmonic analysis method is applied to the harmonic analysis of multi-infeed transmission systems.The result of the research shows that it is practical and effective to apply the modulation iterative harmonic analysis method to analyze the harmonics of the multi-infeed transmission system.At the same time,based on the above research,the input of filter configuration is analyzed and analyzed.It not only promotes the development of harmonic analysis theory,but also has important practical value in engineering practice.