Modelling and Simulation of Electo-quasistatic Fields in Insulator Materials of High-Voltage Direct Current Cables and Cable Terminations with Nonlinear Effects due to Temperature and Space Charge Distributions and Nonlinear Field Grading Materials

• Applicant: Professor Dr. Markus Clemens
• Subject Area: Electrical Energy Systems, Power Management, Power Electronics, Electrical Machines and Drives ; Mathematics
• Term: from 2019 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 420660738

With a growing number of installations of renewable energy sources with long distances to the centers of electric power consumption the use of high voltage direct current (HVDC) electric power transmission increases. The HVDC technology exhibits less loss for long distances of electric energy transport in comparison to high voltage alternating current (HVAC) systems. Modern HVDC cable systems feature polymeric insulation materials, which have good electrical characteristics. A disadvantage of the insulating materials is the possible accumulation of electric space charges which may result in increased local field stresses. These can possibly damage the insulation material and result in a failure of the HVDC cable transmission system.This research proposal focusses on the development of computational simulation models for the electric charge dynamics in insulation materials, especially used in high voltage direct current cables and cable termination systems. Reliable computational simulations of space charge distributions extended mathematical models of HVDC cable insulation properties are to be developed. Based on previous work related to radial symmetric electro-quasistatic models of electric field and space charge distributions, an extended model for the electric conductivity of the insulation material is to be developed to include effects at interfaces and surfaces. This model will allow to consider space charge behavior at interfaces of different dielectric materials. Further, transient voltages, which eventually superimpose the DC voltage, are to be simulated and the resulting space charge behavior is to be analyzed. Three dimensional simulations will be developped to consider effects of temperature or pressure gradient along the cable geometry. In addition, the possible use of electric field grading materials and their effects on space charges distributions will simulated and analysed. Within three dimensional simulation models the HVDC cable system can be computed with highly realistic environment scenarios. Finally, the numerical computation techniques are to be improved to reduce the computation time and increase numerical efficiency. This is mandatory if these simulation schemes are to be used for parameter optimization or for stochastic uncertainty quantification analysis related to input parameters with tolerance uncertainties.

• DFG Programme: Research Grants