In recent years, the Super Grid (large-scale wide-area power grid) that can connect countries and countries, regions and regions has received worldwide attention and various related researches are being conducted. One of the main technologies required for Super Grid is High Voltage Direct Current (HVDC) transmission. In the early 2010s, due to the incident in Milyang, the KEPCO projected 226km from Shin Hanul - Shin Gapyeong to ± 500kV HVDC overhead and underground transmission line (East West Power Grid) project, which is under construction for ROK. In addition, HVDC related projects (North Dangjin - Goguk, Jindo - Jeju, Haenam - Jeju) are in operation.
The HVDC transmission method has a merit that power loss is small during transmission compared with High Voltage Alternating Current (HVAC) transmission method, and long-distance power transmission is possible because there is no loss due to skin effect and reactance component. In addition, since the insulation level is lower than that of the AC transmission system, the size of the transmission tower can be reduced, and thus there is an advantage that the ROW (Right of Way) necessary for constructing the transmission tower can be reduced. Also, There is an advantage in terms of the stability of the electric power system.
HVDC has various advantages as described above. Another important point before constructing and operating the high voltage DC T/L (transmission line) is the electric field analysis through simulation. Since DC has no frequency component unlike AC, voltage and current are always constant even if time changes. Due to this feature, electrostatic field is always formed around the DC T/L. DC electrostatic field don''t induce any electric current or electric field inside human body because there is no induction phenomenon unlike AC electric field. However, since the direct effect of surface charge on the human body and the indirect effect on the charging conductor can cause human irritation such as electrostatic discharges and discomfort, these phenomena should be considered through the environmental impact evaluation when constructing the DC T/L.
Many national standards and reports have limits on the electric field values of DC T/Ls. In addition, there may be complaints related to the corona phenomena, noise characteristics, and ion currents that may occur in the DC T/L. Therefore, it is necessary to conduct a preliminary analysis through simulation to apply the HVDC T/L system. For a reliable DC electric field analysis, a sufficient and accurate understanding of the characteristics of the DC electric field is required. It is also necessary to study the electric field analysis technique which can realize DC electric field.
Studies on the ion generation in the HVDC T/L have been carried out in various aspects of the world. In particular, the generation of ions by the corona discharge is a main cause of the generation of ions in the HVDC T/L. Therefore, the study is proceeding with the aim of analyzing the ion distribution by the corona discharge both domestically and abroad and studying the point of occurrence. As the existing analysis methods, methods using characteristic curve method, iteration method, and elementless method are used. These methods use wind strength, ruggedness of the conductor surface, and ideal assumptions for applying the theoretical equations as needed. Bo Zhang of Tsinghua University in China applies the method of using uniform distribution of conductor surface charge, the method of using distribution of conductor surface charge, the method of using proportional relation between surface electric field and corona generated electric field value to analyze T/L. The plan is under consideration.
This paper describes and analyzes the electric field analysis which should be performed before designing the HVDC T/L. Prior to analyzing the electric field of a DC ± 500kV anode two-wire T/L as a final target, the theory and process related to the DC electric field characteristics were examined, and a DC ± 400kV anode single line model, a DC ± 500kV anode single line model, a DC The simulation results of COMSOL Multiphysics, a multi ? physics analysis program, were compared with the related literature. We also compared the simulation results using COMSOL Multiphysics with the field analysis results using Anypole, a DC field analysis program produced by the Bonneville Power Administration (US BPA).