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 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 420660738

• Final Report Year: 2022

Final Report Abstract

During the project new models were developed and analyzed for the determination of the space charge distribution within cable insulation materials under DC conditions as well as methods for a fast and efficient calculation of the related electric fields. In addition, the effects of various factors, such as voltage shape, temperature distribution or environment, on the electric fields were investigated. In particular, new electric conductivity models were developed, resulting in an improvement of the agreement between the results of space charge simulations and space charge measurements. Theoretical considerations and analytical results of the static charge distribution indicated that an additional spatial variation of the electrical conductivity can reproduce these effects. In order to be able to calculate high fidelity models resulting in high-dimensional discretized problems e.g. by additionally considering the environment of the cable, faster and more efficient procedures were also developed to avoid time consuming coupled electro-thermal calculations. Here, for example, existing analytical results were used. In order to identify field excesses or thermal instabilities, different cable geometries were investigated with a variation of the voltage shape, the environment and the temperature distribution. The conductivity models developed in the project are of practical relevance for the design and layout of cable systems. Failure to account for charge accumulation at boundary layers can lead to partial discharges and a resulting significant reduction of the service lifetime of the insulating material. To be used within time-consuming parameter studies, the developed efficient calculation methods are an important tool to calculate a large variation of scenarios, such as changed dimensions, stresses or material properties, in a short time. A basic understanding of the charging behavior, e.g. at an applied surge voltage or in a buried cable, could be obtained by investigating the effects of various boundary conditions of the cable. In addition to cable geometries, cable joints and cable terminations were also investigated during the project period. Here, too, new models were developed to better describe the charge transport phenomena. Especially at the boundary layers of two different dielectrics, increased electric fields due to charge accumulations were observed, which are insufficiently considered by the conventional simulation models in use so far.

Publications

• Breakdown voltage in high voltage direct current cable insulations considering space charges. 2017 18th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (ISEF) Book of Abstracts, 1-3. IEEE.
  Jorgens, Christoph & Clemens, Markus
  
• Explicit time integration techniques for electro- and magneto-quasistatic field simulations. 2017 International Conference on Electromagnetics in Advanced Applications (ICEAA), 1482-1485. IEEE.
  Dutine, Jennifer; Richter, Christian; Jorgens, Christoph; Schops, Sebastian & Clemens, Markus
  
• Modeling the electric field in polymeric insulation including nonlinear effects due to temperature and space charge distributions. 2017 IEEE Conference on Electrical Insulation and Dielectric Phenomenon (CEIDP), 10-13. IEEE.
  Jorgens, C. & Clemens, M.
  
• Empirical Conductivity Equation for the Simulation of Space Charges in Polymeric HVDC Cable Insulations. 2018 IEEE International Conference on High Voltage Engineering and Application (ICHVE), 1-4. IEEE.
  Jorgens, C. & Clemens, M.
  
• Formulierung einer thermischen Durchschlagbedingung für Kabel der Hochspanungsgleichstromübertragung, 1. VDE Fachtagung für polymere Isolierstoffe und ihre Grenzflächen, 17.-18.05.2018, Zittau, Deutschland, VDE Verlag, S. 17-22. (ISBN: 978-3-00-059755-8)
  C. Jörgens & M. Clemens
  
• Thermal breakdown in high voltage direct current cable insulations due to space charges. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 37(5), 1689-1697.
  Jörgens, Christoph & Clemens, Markus
  
• Comparison of Two Electro-Quasistatic Field Formulations for the Computation of Electric Field and Space Charges in HVDC Cable Systems. 2019 22nd International Conference on the Computation of Electromagnetic Fields (COMPUMAG), 1-4. IEEE.
  Jorgens, Christoph & Clemens, Markus
  
• Conductivity‐based model for the simulation of homocharges and heterocharges in XLPE high‐voltage direct current cable insulation. IET Science, Measurement & Technology, 13(7), 975-983.
  Jörgens, Christoph & Clemens, Markus
  
• Electric Field Model at Interfaces in High Voltage Cable Systems. 2019 19th International Symposium on Electromagnetic Fields in Mechatronics, Electrical and Electronic Engineering (ISEF), 1-3. IEEE.
  Christoph, Jorgens & Clemens, Markus
  
• Empirical Conductivity Equation for the Simulation of the Stationary Space Charge Distribution in Polymeric HVDC Cable Insulations. Energies, 12(15), 3018.
  Jörgens, Christoph & Clemens, Markus
  
• Numerical Simulations of Temperature Stability Limits in High-Voltage Direct Current Cable Insulations. IEEE Transactions on Magnetics, 55(6), 1-4.
  Jorgens, Christoph; Kasolis, Fotios & Clemens, Markus
  
• Numerische Simulation der elektrischen Feldverteilung in Hochspannungs-Gleichstromkabelsystemen unter Berücksichtigung von nichtlinearen Effekten, Dissertation, Bergische Universität Wuppertal, 2019.
  C. Jörgens
  
• Simulation of the Electric Field in High Voltage Direct Current Cables and the Influence on the Environment. Tenth International Conference on Computational Electromagnetics (CEM 2019), 7 (5 pp.)-7 (5 pp.). Institution of Engineering and Technology.
  Jörgens, C. & Clemens, M.
  
• A Review about the Modeling and Simulation of Electro-Quasistatic Fields in HVDC Cable Systems. Energies, 13(19), 5189.
  Jörgens, Christoph & Clemens, Markus
  
• Fast calculation of steady‐state charge distribution in high voltage power cables. International Journal of Numerical Modelling: Electronic Networks, Devices and Fields, 33(5). Portico.
  Jörgens, Christoph & Clemens, Markus
  
• Kernel-Based Regression in Transient Nonlinear Electro-Quasistatic Field Simulations. 2020 IEEE 19th Biennial Conference on Electromagnetic Field Computation (CEFC), 1-4. IEEE.
  Zhang, Dudu; Kasolis, Fotios; Jorgens, Christoph & Clemens, Markus
  
• Modeling the electric field at interfaces and surfaces in high-voltage cable systems. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 39(5), 1099-1111.
  Jörgens, Christoph & Clemens, Markus
  
• Modeling the Electro-Quasistatic Field of Ground Electrodes Under the Influence of Electro-Osmosis. 2020 IEEE 3rd International Conference on Dielectrics (ICD), 513-516. IEEE.
  Jorgens, C. & Clemens, M.
  
• Thermo-elektroquasistationäres Modell zur umgebungsabhängigen Berechnung von Feldbelastungen in Hochspannungs-Gleichstromkabeln, Tagungsband: VDE-Fachtagung Hochspannungstechnik, 09.-11.11.2020, Berlin, Deutschland, VDE Verlag, Berlin, Offenbach, S. 71-76. (ISBN 978-3-8007-5353-6)
  C. Jörgens & M. Clemens
  
• Electric Field and Temperature Simulations of High-Voltage Direct Current Cables Considering the Soil Environment. Energies, 14(16), 4910.
  Jörgens, Christoph & Clemens, Markus
  
• Electric field simulations of field grading techniques in HVDC cable joints. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, 41(4), 1120-1133.
  Jörgens, Christoph & Clemens, Markus