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 - Küchler, Andreas A1 - Liebschner, M. A1 - Reumann, Andreas A1 - Krause, Ch. A1 - Piovan, U. A1 - Heinrich, B. A1 - Fritsche, R. A1 - Hoppe, J. A1 - Langens, Achim A1 - Titze, J. T1 - Evaluation of conductivities and dielectric properties for highly stressed HVDC insulating materials BT - International Paper T2 - CIGRÉ Session 2010 Y1 - 2010 CY - Paris ER - TY - CHAP A1 - Küchler, Andreas A1 - Reumann, Andreas A1 - Liebschner, M. A1 - Böhm, K. A1 - Langens, Achim A1 - Titze, J. A1 - Heil, B. T1 - Online Monitoring of Capacitance and Dissipation Factor of HV Bushings T2 - 16th ISH International Symposium on High Voltage Engineering Y1 - 2009 CY - Cape Town ER - TY - CHAP A1 - Küchler, Andreas A1 - Reumann, Andreas A1 - Liebschner, M. A1 - Langens, Achim A1 - Titze, J. T1 - Online Monitoring of Capacitance and Dissipation Factor Related to Ageing Research Results on OIP T2 - 54th IWK Internationales Wissenschaftliches Kolloquium Ilmenau Y1 - 2009 CY - Ilmenau ER - TY - CHAP A1 - Küchler, Andreas A1 - Reumann, Andreas A1 - Böhm, K. A1 - Langens, Achim A1 - Titze, J. A1 - Heil, B. T1 - Ageing of OIP Bushing Insulation at very High Temperatures T2 - 16th ISH International Symposium on High Voltage Engineering Y1 - 2009 CY - Cape Town ER - TY - CHAP A1 - Küchler, Andreas A1 - Liebschner, M. A1 - Böhm, K. A1 - Reumann, Andreas A1 - Krump, R. A1 - Titze, J. T1 - Online-monitoring of Capacity and Dissipation Factor of High Voltage Bushings at Service Temperature T2 - 15th ISH International Symposium on High Voltage Engineering Y1 - 2007 CY - Ljubljana 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 - 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 - 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 - Hochbrückner, Benedikt A1 - Spiertz, Martin A1 - Küchler, Andreas A1 - Zink, Markus A1 - Steiner, T A1 - Winkelmann, Erik A1 - Krätzschmar, Karsten T1 - Digital filtering methods for interferences on partial discharges under DC voltage Y1 - 2019 ER - TY - JOUR A1 - Schober, Fabian A1 - Küchler, Andreas A1 - Krause, Christoph T1 - Oil conductivity – an important quantity for the design and the condition assessment of HVDC insulation systems JF - FHWS Science Journal N2 - HVDC (high voltage direct current) transmission is a very effective way of power transmission and it is necessary to supply the worlds growing amount of energy. In HVDC equipment the major insulating materials are oil and pressboard. Oil conductivity is an important quantity for the design, the diagnosis and the condition assessment of HVDC insulation systems. Unfortunately, insulating oil has a strongly nonlinear conductivity which depends on various parameters (field strength, temperature, water content and ageing) and is time-dependent because of charge carrier drift processes. Measuring methods are required to provide the information necessary for the condition assessment of HVDC systems. Therefore, measurements of new and aged oils are compared and taken into account for a diagnosis of oil-filled HVDC insulation systems. Furthermore, today’s standards are analyzed and compared to the so called PDC method. Relations between initial and steady-state conductivities at different temperatures, field strengths and for various oil types are presented and consequences for the condition assessment of insulation systems are discussed. KW - Electromobility KW - Energy Engineering KW - HVDC transmission KW - converter transformer KW - insulation Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:863-opus-463 VL - 1 IS - 2 SP - 59 EP - 78 CY - Würzburg ER - TY - CHAP A1 - Hochbrückner, Benedikt A1 - Spiertz, Martin A1 - Küchler, Andreas A1 - Zink, Markus A1 - Steiner, Thomas A1 - Winkelmann, Erik A1 - Krätzschmar, Karsten T1 - Digital Filtering Methods for Interferences on Partial Discharges Under DC Voltage Y1 - 2020 SN - 978-3-030-31675-4 U6 - https://doi.org/10.1007/978-3-030-31676-1_53 SP - 560 EP - 571 ER - TY - CHAP A1 - Hochbrückner, Benedikt A1 - Küchler, Andreas A1 - Spiertz, Martin A1 - Krätzschmar, Karsten A1 - Zink, Markus T1 - Comparison of Algorithms for Clustering of Partial Discharge Signals under DC Voltage Y1 - 2019 U6 - https://doi.org/10.1109/ICHVEPS47643.2019.9011062 ER - TY - CHAP A1 - Küchler, Andreas A1 - Schober, F. A1 - Zink, M. A1 - Liebschner, M. A1 - Krause, Ch. T1 - Diagnosis of HVDC Insulation Systems by use of Oil-conductivity Measuring Methods T2 - 2012 IEEE International Conference on Condition Monitoring and Diagnosis CMD Y1 - 2012 SP - 23 EP - 27 CY - Bali, Indonesia ER - TY - CHAP A1 - Küchler, Andreas A1 - Zink, M. A1 - Berger, Frank A1 - Klipfel, V. T1 - Electrical Simulation as a Tool for Ageing-condition Assessment of Generator Transformer Bushings T2 - 2012 IEEE International Conference on Condition Monitoring and Diagnosis CMD Y1 - 2012 SP - 23 EP - 27 CY - Bali, Indonesia ER - TY - CHAP A1 - Küchler, Andreas A1 - Leibfried, T. A1 - Kachler, A.J. A1 - Zängl, W.S. A1 - Der Houhanessian, V. A1 - Breitenbauch, B. T1 - Ageing and Moisture Analysis of Power Transformer Insulation Systems BT - CIGRÉ 2002 T2 - International Council on Large Electric Systems Y1 - 2002 SP - 12 EP - 101 CY - Paris ER - TY - CHAP A1 - Küchler, Andreas A1 - Dams, J. A1 - Dunz, Th. A1 - Epping, W. A1 - Kunz, H. A1 - Schwab, A. T1 - Kerr-Effect Measurements of Pulsed Electric Fields in Water T2 - 5th IEEE Pulse Power Conf. Y1 - 1985 CY - Arlington VA, USA ER - TY - CHAP A1 - Küchler, Andreas A1 - Dams, J. A1 - Dunz, Th. A1 - Schwab, A. T1 - Design and Operation of a Tera-Watt Pulse-Power Generator T2 - 5th ISH Int. Symp. on High Voltage Engineering Y1 - 1987 SP - 02 EP - 61 CY - Braunschweig ER - TY - CHAP A1 - Küchler, Andreas A1 - Schober, F. A1 - Krieg, A. A1 - Liebschner, M. A1 - Berger, Frank T1 - Parameter influences on HVDC transformer insulation and its link to conduction processes T2 - 32nd International Conference “Science in Practice” Y1 - 2014 CY - Osijek, Croatia 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 - 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 - 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 - Küchler, Andreas A1 - Schober, F. A1 - Exner, W. A1 - Krause, Ch. A1 - Liebschner, M. A1 - Berger, Frank T1 - Interaction of Pressboard with Impregnating Fluids in HVDC Insulation Systems T2 - IEEE Electrical Insulation Conference Y1 - 2014 SP - 276 EP - 280 CY - Philadelphia, Pennsylvania, USA ER - TY - CHAP A1 - Küchler, Andreas A1 - Schober, F. A1 - Liebschner, M. A1 - Berger, Frank A1 - Exner, W. A1 - Krause, Ch. A1 - Fritsche, R. A1 - Wimmer, R. T1 - Dielectric Behaviour of HVDC Insulating Materials, Polarization and Conduction Processes in Mineral Oil and in Pressboard Impregnated with Different Fluids T2 - 19th International Symposium on High Voltage Engineering Y1 - 2015 CY - Pilsen, Czech Repbulic ER - TY - CHAP A1 - Küchler, Andreas A1 - Harrer, S. A1 - Schober, F. A1 - Staab, T. A1 - Sextl, G. A1 - Exner, W. A1 - Krause, Ch. T1 - Influence of Water Content of Cellulosic Material on Dielectric Behaviour of HVDC insulation T2 - 19th International Symposium on High Voltage Engineering Y1 - 2015 CY - Pilsen, Czech Repbulic ER -