| With the continuous construction and development of power system,as well as the successive improvement of voltage level,the problems related to electromagnetic interference are more more serious.Especially to DC converter station in UHV project,the electromagnetic interference also becomes more prominent,due to high voltage level,numerous and complex field equipment.Based on the generation mechanism of electromagnetic interference in UHV DC converter station,this thesis studies the electromagnetic interference and preventive measures in UHV converter station,taking the valve hall system and secondary equipment in converter station as the research object.By studying the electromagnetic interference of valve hall system and secondary equipment,this thesis puts forward scientific preventive measures,which can carry out reasonable design,grasp the severity of electromagnetic interference accurately and prevent underestimation or overestimation,underdesign or overdesign from bringing unnecessary potential safety hazards or economic costs.This thesis studies mainly the electromagnetic interference and preventive measures of ± 800 kV Zarut converter station,focusing on the following aspects:(1)In order to understand the electromagnetic interference level of Zarut converter station,the electromagnetic interference of Zarut converter station is measured on the spot.The measurement conditions,measurement methods,measurement locations and selection of measurement instruments of transient electromagnetic interference and steady-state electromagnetic interference of Zarut converter station are chosen,too.A total of eight measuring points inside and outside Zarut converter station are selected for actual measurement of radio interference under six working conditions.After analyzing and comparing the measured data,it is concluded that the electromagnetic interference in the surrounding area of the converter station meets the requirements of relevant standards.In view of the limitation of actual measurement conditions,the measurement in the valve hall and the port of secondary equipment failed.(2)The radiated electromagnetic interference of Zarut converter station is studied.First,the generation mechanism of radiated electromagnetic interference of Zarut converter station is explored.Then,on the basis of MOM method,the valve hall components and converter valve system such as converter valve transistor,saturation reactor,voltage equalizing capacitor and water-cooling resistance are analyzed,and the broadband equivalent circuit model is established to simulate the electric field intensity in Y direction,radiation intensity at different distances and radiation level under different working conditions.At last,it is concluded that the valve hall is an important electromagnetic interference source,and the effective measures to prevent the electromagnetic interference radiated by the valve hall are formulated.(3)The conducted electromagnetic interference of Zarut converter station is studied.The generation mechanism of conducted electromagnetic interference of Zarut converter station is explored.In addition,the broadband equivalent circuit models of voltage transformer and current transformer are analyzed and established.On this basis,the conducted voltage interference and conducted current interference of secondary equipment circuit under four working conditions are simulated and analyzed.According to the anti-interference performance evaluation and anti-interference performance criteria of secondary equipment,several effective anti-interference preventive measures are introduced in detail,aimed at the conducted voltage interference and conducted current interference of secondary equipment. |
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