TY - CHAP A1 - Targitay, Deniz A1 - Roth, Lisa A1 - Zink, Markus H. A1 - Küchler, Andreas A1 - Bier, Markus A1 - Kobus, Maja A1 - Geißler, Michael A1 - Schlittler, Balz T1 - An FEM simulation model of oil-pressboard insulating systems for HVDC transformers T2 - 23rd International Symposium on High Voltage Engineering (ISH 2023) N2 - In this contribution, a simulation model for the description of the nonlinear dielectric behaviour of an insulation system composed of mineral oil and oil-impregnated pressboard is presented. The model was verified by comparing the simulation results with electric field and current measurements. At the outset, the ideal case, where a homogeneous initial charge carrier distribution according to the definition of ohmic conductivity is present, is analysed to establish the preliminary foundations pertaining to a typical measurement. Following that, the influence of distinct charge carriers on the measured quantities are investigated by altering their parametrisations. In contrast to the ideal case, a real measurement reveals a current trend, that can be explained by an excess amount of initial charge carriers related to the oil-impregnated pressboard layers. Potential possibilities to the origin of the surplus are discussed. Furthermore, it is shown that the dissociable and intrinsic charge carriers alone can reconstruct the measured quantities in terms of the transient behaviour. This points out that, for the field strength studied here ( E ≤ 1 kV/mm ), the charging of the highly resistive pressboard barriers is dominated by the dissociation of charge carriers in the oil gaps. KW - Mineral oil KW - Oil-impregnated pressboard KW - Poisson-Nernst-Planck theory KW - Ion drift KW - Electric current Y1 - 2023 UR - https://doi.org/10.1049/icp.2024.0488 PB - Institution of Engineering & Technology ER - TY - BOOK A1 - Zink, Markus H. T1 - Zustandsbewertung betriebsgealterter Hochspannungstransformatordurchführungen mit Öl-Papier-Dielektrikum mittels dielektrischer Diagnose BT - Dissertation Technische Universität Ilmenau Y1 - 2013 UR - http://permalink.bibkatalog.de/BV041616215 PB - Universitätsverlag Ilmenau CY - Ilmenau ER - TY - BOOK A1 - Zink, Markus H. T1 - Kerntechnik Y1 - 2009 UR - http://permalink.bibkatalog.de/BV023748515 PB - Vogel Fachbuchverlag ER - TY - BOOK A1 - Zink, Markus H. T1 - Kerntechnik Y1 - 2011 UR - http://permalink.bibkatalog.de/BV039571799 PB - Vogel Fachbuchverlag ER - TY - CHAP A1 - Küchler, Andreas A1 - Krieg, A. A1 - Lala, G. A1 - Schober, F. A1 - Wiener, J. A1 - Paulus, J. A1 - Zink, Markus H. A1 - Liebschner, M. T1 - FEM model for describing the dielectric behavior of oil-impregnated pressboard under DC stresses BT - SIP 2015 T2 - 33rd International Conference “Science in Practice” Y1 - 2015 UR - http://permalink.bibkatalog.de/BV042665355 CY - Schweinfurt ER - TY - CHAP A1 - Hartmann, Jürgen A1 - Harrer, S. A1 - Dotterweich, C. A1 - Zink, Markus H. A1 - Hemberger, Frank A1 - Ebert, Hans-Peter A1 - Schnitzler, Tim T1 - Phase change materials for use in thermally and electrically stressed insulation for high voltage applications T2 - 2016 IEEE Electrical Insulation Conference N2 - The temperature of high voltage equipment is often the limiting factor when transmitting electrical energy because the electrical insulation can get severely aged when the temperature is exceeding a certain limit. Hence, cooling has to be improved or heat generation must be reduced to avoid damage of the insulation. In this paper a new method was examined by investigating electrically insulating phase change materials which are able to store latent heat during a phase change from the solid to liquid state in times of high energy demand. To verify the electrically insulating properties of paraffins, one class of phase change materials, a special test cell was designed allowing the determination of breakdown voltage of phase change materials. The measurements on one paraffin sample proved the promising electrical insulating properties and it was shown that the breakdown voltage in the liquid state is comparable … Y1 - 2016 UR - https://ieeexplore.ieee.org/iel7/7541933/7548553/07548675.pdf SN - 978-1-4673-8706-4 SP - 605 EP - 608 PB - IEEE ER - TY - JOUR A1 - Zink, Markus H. A1 - Klipfel, V. A1 - Berger, Frank A1 - Küchler, Andreas A1 - Voll, S. T1 - Der Einfluss von Temperatur und Streukapazität auf diagnostische Kapazitäts- und Verlustfaktormessungen von 400 kV-Hochspannungstransformatordurchführungen JF - ETG-Fachtagung „Diagnostik elektrischer Betriebsmittel“ Y1 - 2012 CY - Fulda ER - TY - CHAP A1 - Zink, Markus H. A1 - Dotterweich, C. A1 - Hartmann, Jürgen A1 - Harrer, S. A1 - Hemberger, F. A1 - Ebert, Hans-Peter A1 - Schnitzler, Tim T1 - Phase Change Materials for Use in Thermally and Electrically Stressed Insulation for High Voltage Applications T2 - IEEE Electrical Insulation Conference Y1 - 2016 VL - 2016 SP - 605 EP - 608 ER - TY - JOUR A1 - Zink, Markus H. A1 - Küchler, Andreas A1 - Berger, Frank T1 - Kompensation des Temperatureinflusses auf dielektrische Messungen im Zeitbereich zur Beschreibung von Isolierwerkstoffen JF - ETG-Fachtagung „Grenzflächen in elektrischen Isoliersystemen“ Y1 - 2013 CY - Dresden ER - TY - CHAP A1 - Zink, Markus H. A1 - Berger, Frank A1 - Klipfel, V. A1 - Küchler, Andreas T1 - Ageing Condition Assessment of 400 kV OIP Generator Transformer Bushings T2 - 17th ISH International Symposium on High Voltage Engineering Y1 - 2011 CY - Hannover ER - TY - CHAP A1 - Hartmann, Jürgen A1 - Harrer, S. A1 - Dotterweich, C. A1 - Zink, Markus H. T1 - On the conduction process of dielectric liquids based on mineral oil BT - International Symposium on High Voltage Engineering 2017 Y1 - 2017 CY - Buenos Aires (Argentinien) ER - TY - CHAP A1 - Küchler, Andreas A1 - Wirth, Isabell A1 - Reumann, Andreas A1 - Zink, Markus H. A1 - Schnitzler, Tim A1 - Langens, Achim A1 - Berger, Frank T1 - Steady-state and Transient Electrical Potential Distributions in HVDC Bushings Measured under Different Thermal Conditions T2 - 19th International Symposium on High Voltage Engineering N2 - High voltage DC (HVDC) applications become more and more important and the voltage level for energy transportation increases steadily. Hence the design of the DC insulation systems becomes more and more difficult. The difference between HVDC and HVAC insulation systems is that in HVAC the electrical field is distributed according to the permittivities of the materials. Permittivity is only weakly dependent on temperature, so there is no significant difference between the electrical field distribution at room temperature and operating temperature of the insulation system. In HVDC however the electrical field is distributed according to the conductivities of the insulation materials whereas the conductivity is strongly dependent on temperature. This can lead to completely different field distributions at varying temperatures. The investigations presented here show simulation results of HVDC bushing cores in comparison with measurements on those test objects. Simulations and measurements were performed both for temperature distributions and electric potentials of the grading layers in the bushing at DC voltage. For the first time, it was shown by experiment that the FEM simulation can reproduce real DC field distributions very well. It was also shown, that there is a strong influence of temperature gradients or temperature transients on transient and steady-state electrical potential distribution inside the insulation. Y1 - 2015 CY - Pilsen, Czech Repbulic ER - TY - CHAP A1 - Wirth, Isabell A1 - Reumann, Andreas A1 - Küchler, Andreas A1 - Schnitzler, Tim A1 - Langens, Achim A1 - Berger, Frank A1 - Zink, Markus H. T1 - Steady-state and Transient Electrical Potential Distribution in HVDC Bushings Measured under Different Thermal Conditions T2 - 19th International Symposium on High Voltage Engineering Y1 - 2015 CY - Pilsen, Czech Republic ER - TY - CHAP A1 - Wirth, Isabell A1 - Reumann, Andreas A1 - Zink, Markus H. A1 - Küchler, Andreas A1 - Langens, Achim A1 - Schnitzler, Tim T1 - Messung elektrischer und thermischer Transienten an Hochspannungsgleichstromdurchführungen T2 - Highvolt Kolloquium, Dresden, 2015 (Poster) Y1 - 2015 ER - TY - CHAP A1 - Wirth, Isabell A1 - Sturm, Sebastian A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Berger, Frank A1 - Schnitzler, Tim T1 - Berücksichtigung von Leitungs- und Polarisationsmechanismen in transienten FEM-Simulationen von HGÜ-Isoliersystemen T2 - VDE-Hochspannungstechnik 2018, Berlin N2 - The calculation of electrical field distributions in insulation systems for high voltage direct current (HVDC) transmission using the finite element method (FEM) usually only considers the dielectric properties in the form of permittivities and conductivities. Due to not sufficiently well simulated transient processes, state of the art is considering the polarization processes by equivalent network models. The application and implementation of polarization mechanisms in a FEM soft- ware closes this gap and allows calculating the electric field distribution more precisely. An implementation of additional differential equations, according to the RC-network model, describing the field dependent polarization mechanisms, are complementing the displacement and conduction current. Material equations and their parameters are determined by measuring the polarization and depolarization currents (PDC). These equations are necessary for both the RC-network models and the differential equations for the FEM. They can be adapted to the actual temperatures in the insulation system. Hence, the necessarily multidimensional electric field calculations of complex insulation systems with stationary or transient temperature-gradients are possible. The described calculation method is verified by reactionless fieldmill voltmeter measurements of transient voltage profiles at the grading foils of modified high voltage DC-bushings. A better accuracy is achieved for the simulation of transient and stationary potential distributions. N2 - Bei der Berechnung elektrischer Feldverteilungen in Isoliersystemen für die Hochspannungsgleichstromübertragung (HGÜ) mit Hilfe der Finiten Elemente Methode (FEM) werden die dielektrischen Eigenschaften bisher meist in Form von Permittivitäten und Leitfähigkeiten berücksichtigt. Da die transienten Verläufe nicht ausreichend genau abgebildet werden, ist Stand der Technik die Polarisationsvorgänge exakter durch Netzwerkmodelle nachzubilden. Durch Implementierung von Polarisationsmechanismen in einem FEM-Programm wurde diese Lücke geschlossen und es können nun elektrische Feldverteilungen vor allem im transienten Zustand wesentlich präziser berechnet werden. In Analogie zum RC-Netzwerkmodell werden hierfür zusätzlich zu den Gleichungen, die die feldabhängigen Verschiebungs- und Leitungsströme beschreiben, weitere Differentialgleichungen eingesetzt, welche die ebenfalls feldabhängigen Polarisationsströme abbilden. Die Materialfunktionen und ihre Parameter werden durch Messung von Polarisations- und Depolarisationsströmen (PDC) ermittelt. Diese Gleichungen werden sowohl für die RC-Netzwerkmodelle als auch für die Aufstellung der Differentialgleichungen für die FEM benötigt. Sie können unmittelbar auf die am jeweiligen Ort im Isoliersystem herrschende Temperatur umgerechnet werden. Somit sind transiente elektrische Feldberechnungen auch für komplexe Isoliersysteme möglich, die sich nur durch mehrdimensionale FEM-Modelle abbilden lassen und in denen oftmals stationäre oder transiente Temperaturgradienten vorliegen. Das beschriebene Berechnungsverfahren wird durch die rückwirkungsfreie Messung transienter Potentialverläufe an den Steuerbelägen von entsprechend modifizierten kondensatorgesteuerten Hochspannungsdurchführungen verifiziert. Dabei kann eine höhere Übereinstimmung der transienten und stationären Potentialverläufe zwischen Simulation und Messung erzielt werden. Y1 - 2018 UR - https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=8576769 ER - TY - CHAP A1 - Koch, Myriam A1 - Hohloch, Jens A1 - Wirth, Isabell A1 - Sturm, Sebastian A1 - Zink, Markus H. A1 - Küchler, Andreas T1 - Experimental and simulative analysis of the thermal behavior of high voltage cable joints T2 - VDE-Hochspannungstechnik 2018, Berlin N2 - Nowadays, cable systems are often preferred when deciding on the type of new transmission lines even in the high and extra high voltage range. One of the main reasons is the better public acceptance. In addition, the power to be transmitted in the grid is increasing leading to increased ohmic losses and thus, to higher thermal stress on the materials. The investigations in this contribution focus on cable joints, which represent important and decisive components of cable systems. In order to optimize the design and to ensure reliable operation over the entire service life, the temperature profile within these components is of special interest. For their detailed investigation, a test circuit was set up consisting of a cable section and sections with build-up stages of a cable joint. A large number of measuring points were defined also at points where no measurement is possible in normal operation. With a thermographic camera the surface temperature distributions were observed. With the laboratory setup temperature profiles under various load conditions were recorded. A detailed FEM model was built and verified with help of these measurements. The model permits the investigation of specific questions of cable systems such as the comparison of temperature loads resulting from normal operating conditions and of test procedures according to the relevant standards. Besides others the effect of stressing the insulation and sealing system by heating the inner conductor vs. heating from outside by surrounding water is discussed. Y1 - 2018 UR - https://ieeexplore.ieee.org/document/8576752 ER - TY - CHAP A1 - Wirth, Isabell A1 - Reumann, Andreas A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Berger, Frank A1 - Langens, Achim A1 - Schnitzler, Tim A1 - Heil, B. T1 - Measurement and simulation of transient field stresses and impacts on advanced insulation design and new test procedures for HVDC components T2 - Cigre-Konferenz, Paris Y1 - 2020 ER - TY - CHAP A1 - Wirth, Isabell A1 - Heßdörfer, Nadja A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Langens, Achim A1 - Berger, Frank T1 - Measurements and calculations of critical thermal and electrical stress conditions for HVDC bushings T2 - 20th International Symposium on High Voltage Engineering, Buenos Aires, 2017 Y1 - 2017 ER - TY - CHAP A1 - Hopf, K. A1 - Wirth, Isabell A1 - Sturm, Sebastian A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Langens, Achim T1 - Temperature-dependent and anisotropic electrical conductivity of resin-impregnated paper T2 - Power and Energy Student Summit, Nürnberg, 2017 Y1 - 2017 ER - TY - CHAP A1 - Wirth, Isabell A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Berger, Frank A1 - Langens, Achim T1 - Elektrische Feldverteilung und Polarisationsströme in HGÜ Durchführungen T2 - Fachtagung Polymere Isolierstoffe und ihre Grenzflächen, Zittau, 2018 Y1 - 2018 ER - TY - CHAP A1 - Sturm, Sebastian A1 - Wirth, Isabell A1 - Paulus, Johannes A1 - Zink, Markus H. A1 - Küchler, Andreas A1 - Berger, Frank T1 - Transient dielectric simulation in time domain with FEM in comparison with circuit models T2 - XIX International Symposium on Theoretical Electrical Engineering, Ilmenau, 2017 Y1 - 2017 ER - TY - CHAP A1 - Krieg, Andreas A1 - Lala, Gjergj A1 - Schober, Fabian A1 - Wiener, Johannes A1 - Paulus, Johannes A1 - Küchler, Andreas A1 - Zink, Markus H. A1 - Liebschner, Marcus T1 - FEM model for describing the dielectric behavior of oil-impregnated pressboard under DC stresses T2 - Papers of 33rd International Scientific Conference "Science in Practice" N2 - According to the worldwide growing demand for electric energy, it is necessary to construct safe and efficient power systems. HVDC (high voltage direct current) applications become more and more important due to larger distances for the energy transportation and the increasing demand for reactive power transportation. Appropriate insulation materials, i.e. mineral oil and pressboard, are widely used in HVDC components, mainly in power transformers though the knowledge about dielectric behavior of oil-impregnated pressboard under DC stresses in time domain is not sufficient. In this paper, a Finite Element Method (FEM) model is presented to describe the electrical conduction behavior of the material by separate consideration of mineral oil and pressboard. With this model the electric potential distribution under DC stress was simulated to analyze polarization and electrical conduction. The model parameters volume ratio as well as angle variations of FEM model are investigated and their influences on the current through the model are evaluated. Furthermore, geometrical and physical parameters are estimated and the results are compared to currents that are measured on oil-impregnated pressboard samples in time domain. KW - electrical conduction KW - FEM simultation KW - HVDC KW - polarization KW - oil-impregnated pressboard Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-2609 SP - 62 EP - 66 ER -