TY - CHAP A1 - Rahimpour, Ebrahim A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza T1 - Evaluating the Influence of External Compensators on Chopped Impulse Waves in Power Transformer Testing T2 - 2024 IEEE International Conference on High Voltage Engineering and Applications, Berlin, Germany N2 - Applying lightning impulse tests on high-voltage transformers plays a crucial role in evaluating their insulation system. The performance of the dielectric system in newly produced power transformers must satisfy the requirements of both full and chopped wave tests. To conduct these tests, standard full and chopped impulses are generated using the well-known Marx generator. The wave shape parameters of these impulses must fulfil the requirements that are specified in international standards such as IEC 60076. The excessive voltage collapse rate as well as the high amplitude of the first peak of the resulting overswing following the chopping time, highly stress the dielectric system of the power transformers. To resolve these issues, external elements may be added to the chopping circuit. These additional elements are essential in stabilizing the waveform by preventing excessive voltage collapse rate and controlling the peak of the first swing after chopping. Furthermore, some transformers with high power ratings may possess windings with very low inductance or high capacitance, which can undesirably impact the shape and parameters of the resulting full wave. To address these critical situations and bring the full wave parameters within the allowed limits, engineers in high-voltage laboratories employ some compensators like the Glaninger circuit in impulse circuits. It is important to study the effects of such compensators on chopped impulse parameters. This paper aims to investigate the impact of the mentioned external elements and compensators on the parameters of the chopped wave impulses. Specifically, the study focuses on assessing the influence of these compensators on voltage collapse and the peak amplitude of the first swing after chopping. By analyzing and understanding these effects, researchers and engineers can gain valuable insights into the performance and optimization of lightning impulse tests on power transformers, ultimately contributing to the advancement of high-voltage laboratory practices. KW - Marx impulse generator KW - Lightning impulse test KW - chopped wave KW - Overswing KW - Compensator Y1 - 2024 SN - 979-8-3503-7498-8 U6 - https://doi.org/10.1109/ICHVE61955.2024.10676122 SP - 969 EP - 972 PB - IEEE ER - TY - CHAP A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza A1 - Rahimpour, Ebrahim A1 - Rabih, S. T1 - Analyzing the Possibility of Improving Waveform Shape in Lightning Impulse Testing of Distribution Transformers T2 - 28th Electrical Power Distribution Conference, Zanjan, Iran Y1 - 2024 SP - 1 EP - 5 ER - TY - CHAP A1 - Rahimpour, Ebrahim A1 - Al-Abadi, A. A1 - Gamil, A. T1 - Dynamisches Feuchtigkeitsgleichgewicht in flüssigkeitsgefüllten Transformatoren T2 - 17th Transformer-Life-Management Konferenz, Zeulenroda, Germany, 16-17 September 2024 Y1 - 2024 ER - TY - CHAP A1 - Rahimpour, Ebrahim T1 - Herausforderungen der Blitzstoßspannungsprüfung an Leistungstransformatoren - Überblick über die CIGRE Arbeitsgruppe A2.63 T2 - 16th Transformer-Life-Management Konferenz Y1 - 2023 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part E: Measurements and transformer design details JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 904 Y1 - 2023 SN - 978-2-8587-3609-6 SP - 1 EP - 140 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part D: Model interfacing and specifications JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 903 Y1 - 2023 SN - 978-2-8587-3608-9 SP - 1 EP - 43 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part B: Black-Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 901 Y1 - 2023 SN - 978-2-8587-3606-5 SP - 1 EP - 88 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part A: White-Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 900 Y1 - 2023 SN - 978-2-8587-3605-8 SP - 1 EP - 203 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies, Part C: Grey Box Models JF - Conseil International des Grands Réseaux Électriques (CIGRE) TB 902 Y1 - 2023 SN - 978-2-8587-3607-2 SP - 1 EP - 102 ER - TY - JOUR A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An improvement in the design process of sustainable peak power rating transformer for solar utility JF - International Journal of Electrical Power & Energy Systems N2 - The transformer industry faces critical challenges, such as maintaining reliable production while meeting rising sustainability requirements. This paper introduces a significant advancement in the design and optimization of a transformer dedicated to a photovoltaic power plant, which exhibits a unique loading cycle distinct from standard power and distribution transformers. The main aim is to minimize the carbon footprint by enhancing the design process to improve operational performance, efficiency, and functional reliability. Such upgrades are essential for transitioning to a zero-emission electricity system and developing green energy projects. In this paper, a transformer has been studied using a combination of electrical design and 3D finite element method simulation to evaluate various design parameters. An optimization study has been conducted using an innovative multi-objective genetic algorithm utilizing a cost function that factors in size and material costs to identify the most efficient and cost-effective design solutions. The proposed design method was then validated through thermal model simulations and experimental tests based on the photovoltaic load cycle. A comparison of critical thermal parameters directly affecting the transformer’s lifetime and reliability was also drawn. The results were consistent with the expected outcomes, confirming the effectiveness and reliability of the proposed design methodology. KW - Transformer KW - Photovoltaic KW - Finite element method KW - Optimization KW - Genetic algorithm Y1 - 2025 U6 - https://doi.org/https://doi.org/10.1016/j.ijepes.2025.110928 SN - 0142-0615 VL - 170 SP - 1 EP - 13 PB - Elsevier BV ER - TY - CHAP A1 - Yükselen, Emir A1 - Rahimpour, Ebrahim T1 - An Optimization Approach for Sustainable Transformer Design in Photovoltaic Power Plants”, 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy T2 - 4th IEEE International Conference on Power Electronics Smart Grid and Renewable Energy Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim T1 - Analyzing of Non-Standard Overvoltages in Different Types of Power Transformer Windings Using Frequency Domain and Time Domain Severity Factors T2 - CIGRE SC A2 & D1 Joint Colloquium Y1 - 2025 ER - TY - CHAP A1 - Rahimpour, Ebrahim A1 - Portillo, A. A1 - Dragostinov, S. T1 - Testing Challenges in Impulse Testing of Transformers T2 - CIGRE SC A2 & D1 Joint Colloquium Y1 - 2025 ER - TY - CHAP A1 - Abouhosseini-Darzi, Mohammad A1 - Rahimpour, Ebrahim A1 - Mirzaie, Mohammad A1 - Shayegani Akmal, Amir Abbas T1 - Investigating the Effects of Moisture Distribution on the Electric Field and Leakage Current of Power Transformer Bushings T2 - IEEE Electrical Insulation Conference (EIC) N2 - Bushings are one of the most important and essential equipment of power transformers. Statistics show that one of the main causes of transformer failures is due to bushing problems. One of the main reasons for bushing failures is the penetration of moisture into its internal insulation system. The moisture affects the dielectric properties and leads to an increase in its leakage current. These effects lead to changes in the electric field of the inner insulating layers of the bushings, so it is necessary to investigate these effects. In this paper, the changes of the electric field in the insulating layers of a sample bushing have been investigated with considering the different moisture distribution between the layers. This evaluation has been done during the moisture diffusion time, from the start of penetration to the time of uniformity of moisture in all layers. Also, the moisture effects on the bushing leakage current under above conditions have been studied. For this purpose, an OIP bushing is modeled in COMSOL Multiphysics software and the simulations are carried out based on Finite Element Method (FEM) and finally the obtained results are analyzed. The results show that the moisture distribution in the bushing can have an important effect on the internal electric fields. Also, according to the results, the moisture distribution inside the bushing does not have a great effect on the leakage current and this current is only affected by the volume of the moisture penetrated inside the bushing. KW - Multiphysics KW - Analytical models KW - Moisture KW - Insulators KW - Software KW - Finite element analysis KW - Leakage currents KW - Reliability KW - Electric fields KW - Power transformer insulation KW - Transformer Bushing KW - Moisture Content KW - Electric Field Distribution KW - Leakage Current KW - Finite Element Method (FEM) KW - Transformative Power KW - Moisture Distribution KW - Finite Element Method KW - Effect Of Moisture KW - COMSOL Multiphysics Software KW - Internal Electric Field KW - Insulation System KW - Moisture Diffusion KW - Conductive KW - Dielectric Constant KW - Relaxation Time KW - Distribution Of Effects KW - Aluminum Foil KW - Radial Direction KW - Axial Direction KW - Electric Distribution KW - Concentric Layers KW - Maximum Field KW - Maximum Electric Field KW - Resistance Components KW - Average Moisture Content KW - Capacitive Component KW - Relative Electrical Conductivity KW - Complex Relative Permittivity KW - Amount Of Moisture Y1 - 2025 SN - 979-8-3315-2608-5 U6 - https://doi.org/10.1109/EIC63069.2025.11123376 SN - 2993-3684 PB - IEEE ER - TY - JOUR A1 - Abouhosseini-Darzi, Mohammad A1 - Mirzaie, Mohammad A1 - Shayegani Akmal, Amir Abbas A1 - Rahimpour, Ebrahim T1 - Calculation and Analysis of the Electric Field of the OIP Bushings under Internal Humidity and Surface Polluted Conditions using FEM JF - Iranian Journal of Electrical and Electronic Engineering N2 - Bushings are one of the most important components of electrical equipment such as power transformers, reactors, capacitors. Most of the installed bushings have Oil-Immersed Paper (OIP) insulation structure. Bushing failure is caused by various reasons such as poor manufacturing process, overloading and also poor installation process, but moisture ingress is one of the main reasons of OIP bushing defect during its operation. In this paper, the electric field distribution of OIP bushings in multiple situations are simulated and effects of moisture distribution are analyzed. The simulations are stablished in polluted and clean surfaces of the studied bushing and done by COMSOL Multiphysics Software. The results show that non-uniform moisture distribution has a significant effect on electric fields of OIP insulation. This effect strongly increases with increasing the pollution on the external insulator of the bushing. © 2025, Iran University of Science and Technology. All rights reserved. KW - Finite Element Method (FEM) KW - Moisture KW - OIP Bushing KW - Pollution KW - Transformer Y1 - 2025 U6 - https://doi.org/10.22068/IJEEE.21.3.3360 VL - 21 IS - 3 SP - 1 EP - 11 ER - TY - CHAP A1 - Al-Abadi, A. A1 - Rahimpour, Ebrahim A1 - Gamil, Ahmed T1 - Dynamisches thermisches Verhalten von mit Ester-Flüssigkeit gefüllten Transformatoren für Offshore-Windkraftanwendungen in kalten Klimazonen T2 - 18th Transformer-Life-Management Konferenz Y1 - 2025 ER - TY - CHAP A1 - Rahimpour, Ebrahim A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza T1 - Application of the Nonlinear Kernel Principal Component Analysis in Detecting Disk-to-Disk Faults along a Transformer Winding T2 - 3rd International Conference – Tesla Innovation Days Y1 - 2025 ER - TY - CHAP A1 - Ghorbal, Mohammed Bilal A1 - Mirzaei, Hassan Reza A1 - Rahimpour, Ebrahim T1 - Detection of Disk Space Variation in Power Transformers using Nonlinear Dimensionality Reduction Algorithm T2 - 24th International Symposium on High Voltage Engineering Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim A1 - Eslamian, Morteza T1 - An Inductance Matrix Expansion Method for Transient Analysis of Power Transformer using Single Turn Model T2 - 24th International Symposium on High Voltage Engineering Y1 - 2025 ER - TY - CHAP A1 - Meuser, Martin A1 - Rahimpour, Ebrahim A1 - Eslamian, Morteza T1 - Induktivitätsmatrixerweiterung für die Transientenanalyse in Leistungstransformatoren T2 - 18th Transformer-Life-Management Konferenz Y1 - 2025 ER - TY - JOUR A1 - Gustavsen, B. A1 - Rahimpour, Ebrahim T1 - High-Frequency Transformer and Reactor Models for Network Studies JF - Electra Y1 - 2023 IS - 328 SP - 1 EP - 13 ER -