HVDC单极-大地运行情况下换流变压器直流偏磁建模仿真

Simulation analysis of convert transformer DC-biasing under HVDC system in ground return operation

阐述变压器直流偏磁主要研究动向、研究需求和分析方法,提出一种评估交流变压器中性点直流偏磁与高压直流输电系统(HVDC)运行方式关系的仿真模型.以天广直流输电系统工程为例,根据实际参数对CIGRE HVDC标准模型控制系统进行修改和补充,运用PSCAD/EMTDC电磁暂态仿真软件,建立南网天广直流输电单极-大地运行模型.该模型可基于电路元件等值方法对换流变压器直流偏磁电流随系统运行方式变化的规律进行仿真模拟,对各种运行工况下换流变压器直流偏磁进行仿真,并建立单极运行时传输功率与换流变压器中性点电流的映射关系.

This paper analyzed current transformer DC bias research trend, research needs and analysis method of the DC basis, and established a simulation model to evaluate the relationship between the AC transformer neutral point DC bias and operation mode of high voltage direct current （HVDC） transmis- sion system. Taking the Tian-Guang DC transmission system engineering as an example, CIGRE HVDC standard model control system with the actual parameters was modified. By using PSCAD/EMTDC elec- tromagnetic transient simulation software, the ground return operation mode of Tian-Guang HVDC transmission system was built up. Based on circuit element equivalents, this model could simulate the re- lationship between converter transformer DC bias current and system operation. After the Simulatiort ofconverter transformers DC bias on a variety of operating conditions, the relationship of converter trans- former neutral point current and the transmission power was established.