户内大容量水冷柔直变压器的设计

柔性直流输电工程建设在大电网负荷中心,站址紧邻居民区。这对柔直变压器在大容量、安全性和低噪声等方面提出了更高的要求。本文针对柔直变压器产品容量大、首次采用户内布置,套管升高座穿墙,均从侧壁引出、采用水冷却方式、全新的阀侧线端操作冲击耐压试验等方面介绍了户内布置的大容量柔性直流输电用柔直变压器设计研发情况。     

交直流复合电压下油纸绝缘气隙局部放电与产气特性分析(英文)

Oil-paper insulation is used within most of high voltage direct current(HVDC) converter transformers.Partial discharge(PD) in oil-paper insulation is a major reason for the development of internal faults in HVDC converter transformer,while PDs in oil-paper insulation mainly occur in terms of gas cavity discharges.There are few study results on the development characteristics of partial discharges in oil-paper insulation and dissolved gases in oils of HVDC converter transformers.Based on a gas cavity discharge model of oil-paper insulation,the present study investigates the development characteristics of partial discharges under AC-DC combined voltages and emphatically examines the variation characteristics of dissolved gases in the discharge development process.Experiment and analysis results show that the characteristics of partial discharges and dissolved gases in oils under AC-DC combined voltages are appreciably different with those under AC voltage.These results provide theoretical support for further research on partial discharges and on dissolved gases of other internal insulating defects and are helpful for the fault diagnosis of HVDC converter transformers.     

交直流复合电压下的油纸绝缘局部放电统计图谱研究(英文)

The converter transformer is one of the most critical equipments in high-voltage direct current transmission systems.Valve-side windings have to withstand complex stresses combined of AC,DC,and pulsed voltages.Partial discharges(PDs) can thus easily occur in oil-impregnated paper insulation.The current paper presents the statistical phase-resolved distributions of partial discharges in oil-paper insulation under combined AC and DC voltage stress.First,the voltages in the converter transformer were analyzed.In the experiments,four artificial insulation defect models were designed to generate PD signals under AC-DC combined voltage stress detected by a Rogowski coil sensor.Histograms including the φ-q-n data of these PD signals were created.The variations of φ-q-n data generated by PDs in different insulation defect models were analyzed while increasing the test voltage.Experimental results showed that the PD phase-resolved distributions of different insulation defect models were different from one another.The findings of the current study are useful in further research on the mechanism and pattern recognition of PDs in converter transformers.     

换流变压器出厂试验中典型绝缘故障统计与分析

本文介绍了换流变压器绝缘试验项目及考核目的,梳理统计了国内多个直流工程中换流变压器出厂试验过程中的出现的典型绝缘故障案例,统计结果表明,换流变压器出厂试验中绝缘故障主要出现在温升试验、感应耐压试验、阀侧外施交流试验等试验项目中.针对典型绝缘故障,从设计、原材料及组部件、制造工艺控制等方面分析了导致绝缘故障的原因.最后提...