Research On The Principle And Method Of The Filter In The Novel HVDC Transmission System

Harmonics suppression is a key technologic problem in HVDC. Due to the nonlinear characteristics of the converter, harmonics voltages and currents occur in AC and DC system. The harmonics currents generated by the AC system of the converter station result in the harmonics voltages and currents distribution in AC system, thus the voltage waveform distortion occurred; The harmonics voltages generated by the DC system of the converter station also result in the harmonics voltages and currents distribution in DC system, thus the neighboring communication lines are disturbed. To suppress the harmonic voltages and currents, some measures must be taken.This paper combines the key science & technology project 05GK1001-2 of the Tenth Five Year Plan of Hunan Province– research & manufacture of new-style converter transformer in HVDC power transmitting system, making deep research on the principle of the novel direct current transmission filter, the filter scheme and the filter design.This paper introduces the harmonic problem existed in the electric power system and the research status and analyses the reason and the hazard produced by harmonic waves and represents the method to suppress the harmonic waves. This paper represents the operation principle of HVDC transmission system, analyses the harmonic component and feature in the AC side and the DC side, researches on the design method of the filter and compares the design difference between the filters in the AC side and the DC side.This paper researches on the filter principle and the filter method of the novel HVDC transmission system and analyses in detail the phase-shifting principle and the effect of the harmonic suppression of the novel converter transformer used in the system. This paper analyses the feature of the single tuning filter, the double tuning filter and the high-pass filter. A design scheme based on the matched filter device of the novel converter transformer and a design illustration is given.This paper designs a filter device based on the novel HVDC transmission system test platform, calculates and deduces the filter parameters and analyses the performance of the filter. The test platform is explored by the Simulink simulation software. The filter designed is proved by the filter model and system model designed by Simulink. The simulation and the actual measurement show that the distortion factor of the voltage and the current of the filter scheme designed in this paper is lower obviously than the conventional one, which declares that the design method is right and the structure and the parameters of the filter device is proper.