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Schurch R, Munoz O, Ardila-Rey J, Donoso P, Peesapati V. Identification of Electrical Tree Aging State in Epoxy Resin Using Partial Discharge Waveforms Compared to Traditional Analysis. Polymers (Basel) 2023; 15:polym15112461. [PMID: 37299260 DOI: 10.3390/polym15112461] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Revised: 05/13/2023] [Accepted: 05/19/2023] [Indexed: 06/12/2023] Open
Abstract
Electrical treeing is one of the main degradation mechanisms in high-voltage polymeric insulation. Epoxy resin is used as insulating material in power equipment such as rotating machines, power transformers, gas-insulated switchgears, and insulators, among others. Electrical trees grow under the effect of partial discharges (PDs) that progressively degrade the polymer until the tree crosses the bulk insulation, then causing the failure of power equipment and the outage of the energy supply. This work studies electrical trees in epoxy resin through different PD analysis techniques, evaluating and comparing their ability to identify tree bulk-insulation crossing, the precursor of failure. Two PD measurement systems were used simultaneously-one to capture the sequence of PD pulses and another to acquire PD pulse waveforms-and four PD analysis techniques were deployed. Phase-resolved PD (PRPD) and pulse sequence analysis (PSA) identified tree crossing; however, they were more sensible to the AC excitation voltage amplitude and frequency. Nonlinear time series analysis (NLTSA) characteristics were evaluated through the correlation dimension, showing a reduction from pre- to post-crossing, and thus representing a change to a less complex dynamical system. The PD pulse waveform parameters had the best performance; they could identify tree crossing in epoxy resin material independently of the applied AC voltage amplitude and frequency, making them more robust for a broader range of situations, and thus, they can be exploited as a diagnostic tool for the asset management of high-voltage polymeric insulation.
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Affiliation(s)
- Roger Schurch
- Department of Electrical Engineering, Universidad Tecnica Federico Santa Maria, Valparaiso 2390123, Chile
| | - Osvaldo Munoz
- Department of Engineering and Design, Chilean Independent System Operator, Santiago 9020000, Chile
| | - Jorge Ardila-Rey
- Department of Electrical Engineering, Universidad Tecnica Federico Santa Maria, Valparaiso 2390123, Chile
| | - Pablo Donoso
- Department of Electrical and Electronic Engineering, The University of Manchester, Manchester M13 9PL, UK
| | - Vidyadhar Peesapati
- Department of Electrical and Electronic Engineering, The University of Manchester, Manchester M13 9PL, UK
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Corona Resistance Mechanism of Nano-Modified Polyimide. Polymers (Basel) 2022; 14:polym14245469. [PMID: 36559836 PMCID: PMC9788342 DOI: 10.3390/polym14245469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/19/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Abstract
In this paper, the effect of field strength on the corona-resistant lifespan of a composite film and the effect of doping on the dielectric properties of the composite film were studied. The method for predicting corona-resistant lifespan under working electric field strength is discussed. Scanning electron microscopy (SEM) was used to characterize the morphology and the structure of the composite film near the breakdown point after corona formation. Fourier transform infrared spectroscopy (FT-IR) was used to characterize the imidiated film, and a conductivity current test was used to calculate the electrical aging threshold of the film. The results showed that the introduction of nano-SiO2 particles could greatly improve the corona-resistant lifespan of the material. At 155 °C, when the applied external electric field strength was extrapolated to 20 kV/mm, the corona-resistant lifespan of the PI/nano-SiO2 three-layer composite film with 10 wt% nano-particle doping was 7472.61 h.
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Awais M, Chen X, Dai C, Wang Q, Meng FB, Hong Z, Paramane A, Tanaka Y. Investigating optimal region for thermal and electrical properties of epoxy nanocomposites under high frequencies and temperatures. NANOTECHNOLOGY 2022; 33:135705. [PMID: 34936998 DOI: 10.1088/1361-6528/ac45c3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/22/2021] [Indexed: 06/14/2023]
Abstract
This research investigates the optimal region to achieve balanced thermal and electrical insulation properties of epoxy (EP) under high frequency (HF) and high temperature (HT) via integration of surface-modified hexagonal boron nitride (h-BN) nanoparticles. The effects of nanoparticle content and high temperature on various electrical (DC, AC, and high frequency) and thermal properties of EP are investigated. It is found that the nano h-BN addition enhances thermal performance and weakens electrical insulation properties. On the other side, under HF and HT stress, the presence of h-BN nanoparticles significantly improves the electrical performance of BN/EP nanocomposites. The EP has superior insulation properties at low temperature and low frequency, whereas the BN/EP nanocomposites exhibit better insulation performance than EP under HF and HT. The factors such as homogeneous nanoparticle dispersion in EP, enhanced thermal conductivity, nanoparticle surface modification, weight percent of nanoparticles, the mismatch between the relative permittivity of EP and nano h-BN, and the presence of voids in nanocomposites play the crucial role. The optimal nanoparticle content and homogenous dispersion can produce suitable EP composites for the high frequency and high temperature environment, particularly solid-state transformer applications.
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Affiliation(s)
- Muhammad Awais
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
| | - Xiangrong Chen
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
- International Research Center for Advanced Electrical Engineering, International Campus Zhejiang University, Haining 314400, People's Republic of China
| | - Chao Dai
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
| | - Qilong Wang
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
| | - Fan-Bo Meng
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
| | - Zelin Hong
- College of Electrical Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China
- Hangzhou Global Scientific and Technological Innovation Center Zhejiang University, Hangzhou 311200, People's Republic of China
| | - Ashish Paramane
- Electrical Engineering Department National Institute of Technology Silchar, Assam, 788010, India
| | - Yasuhiro Tanaka
- Measurement and Electric Machine Control Laboratory, Tokyo City University, Tamazutsumi, Setagaya 158-8557, Tokyo, Japan
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Investigation of Factors Affecting Partial Discharges on Epoxy Resin: Simulation, Experiments, and Reference on Electrical Machines. ENERGIES 2021. [DOI: 10.3390/en14206621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In Power Systems, Synchronous Generators (SGs) are mostly used for generating electricity. Their insulation system, of which epoxy resin is a core component, plays a significant role in reliable operation. Epoxy resin has high mechanical strength, a characteristic that makes it a very good material for reliable SG insulation. Partial Discharges (PDs) are a constant threat to this insulation since they cause deterioration and consequential degradation of the aforementioned material. Therefore, it is very important to detect PDs, as they are both a symptom of insulation deterioration and a means to identify possible faults. Offline and Online PDs Tests are described, and a MATLAB/Simulink model, which simulates the capacitive model of PDs, is presented in this paper. Moreover, experiments are carried out in order to examine how the flashover voltage of epoxy resin samples is affected by different humidity levels. The main purpose of this manuscript is to investigate factors, such as the applied voltage, number, and volume of water droplets and water conductivity, which affect the condition of epoxy resin, and how these are related to PDs and flashover voltages, which may appear also in electrical machines’ insulation. The aforementioned factors may affect the epoxy resin, resulting in an increase in PDs, which in turn increases the overall Electrical Rotating Machines (EMs) risk factor.
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Bhutta MS, Akram S, Meng P, Castellon J, Agnel S, Li H, Guo Y, Rasool G, Hussain S, Nazir MT. Steady-State Conduction Current Performance for Multilayer Polyimide/SiO 2 Films. Polymers (Basel) 2021; 13:polym13040640. [PMID: 33669983 PMCID: PMC7924843 DOI: 10.3390/polym13040640] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 01/28/2021] [Accepted: 02/02/2021] [Indexed: 11/16/2022] Open
Abstract
The steady-state electrical conduction current for single and multilayer polyimide (PI) nanocomposite films was observed at the low and high electric field for different temperatures. Experimental data were fitted to conduction models to investigate the dominant conduction mechanism in these films. In most films, space charge limited current (SCLC) and Poole–Frenkel current displayed dominant conduction. At a high electric field, the ohmic conduction was replaced by current–voltage dependency. Higher conduction current was observed for nanocomposite films at a lower temperature, but it declined at a higher temperature. PI nanocomposite multilayer films showed a huge reduction in the conduction current at higher electric fields and temperatures. The conclusions derived in this study would provide the empirical basis and early breakdown phenomenon explanation when performing dielectric strength and partial discharge measurements of PI-based nanocomposite insulation systems of electric motors.
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Affiliation(s)
- Muhammad Shoaib Bhutta
- Binjiang College, Nanjing University of Information Science & Technology, Wuxi 214105, China; (M.S.B.); (H.L.); (Y.G.); (G.R.)
| | - Shakeel Akram
- College of Electrical Engineering, Sichuan University, Chengdu 610065, China;
- Institut d’Electronique et des Systèmes, University of Montpellier, 34090 Montpellier, France; (J.C.); (S.A.)
| | - Pengfei Meng
- College of Electrical Engineering, Sichuan University, Chengdu 610065, China;
- Correspondence:
| | - Jerome Castellon
- Institut d’Electronique et des Systèmes, University of Montpellier, 34090 Montpellier, France; (J.C.); (S.A.)
| | - Serge Agnel
- Institut d’Electronique et des Systèmes, University of Montpellier, 34090 Montpellier, France; (J.C.); (S.A.)
| | - Hui Li
- Binjiang College, Nanjing University of Information Science & Technology, Wuxi 214105, China; (M.S.B.); (H.L.); (Y.G.); (G.R.)
| | - Yecai Guo
- Binjiang College, Nanjing University of Information Science & Technology, Wuxi 214105, China; (M.S.B.); (H.L.); (Y.G.); (G.R.)
| | - Ghulam Rasool
- Binjiang College, Nanjing University of Information Science & Technology, Wuxi 214105, China; (M.S.B.); (H.L.); (Y.G.); (G.R.)
| | - Shahid Hussain
- School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013, China;
| | - Muhammad Tariq Nazir
- School of Mechanical and Manufacturing Engineering, University of New South Wales, Sydney, NSW 2052, Australia;
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Lin S, Zhou K, Li Y, Meng P. Water Tree Propagation in a Wide Temperature Range: Insight into the Role of Mechanical Behaviors of Crosslinked Polyethylene (XLPE) Material. Polymers (Basel) 2020; 13:polym13010040. [PMID: 33374277 PMCID: PMC7795215 DOI: 10.3390/polym13010040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/17/2020] [Accepted: 12/17/2020] [Indexed: 11/26/2022] Open
Abstract
To understand the propagation characteristics of water trees at a wide temperature range, this paper presents the effect of mechanical behaviors on the sizes of water trees. An accelerated water tree aging experiment was performed at −15 °C, 0 °C, 20 °C, 40 °C, 60 °C, and 80 °C for crosslinked polyethylene (XLPE) specimens, respectively. Depending on the micro observations of water tree slices, water tree length is not always increasing with the increase in temperature. From 0 °C to 60 °C, water tree length shows a trend from decline to rise. Above 60 °C, water tree length continues to reduce. Dynamic mechanical analysis (DMA) shows that the glass transition temperature of the new XLPE specimen is about −5 °C, and the α-relaxation is significant at about 60 °C. With the increase in temperature, the XLPE material presents different deformation. Meanwhile, according to the result of the yield strength of XLPE at different temperatures, with the increase in temperature, the yield strength decreases from 120 MPa to 75 MPa, which can promote the water tree propagation. According to the early stage in the water tree propagation, a water tree model was constructed with water tree branches like a string of pearls to calculate electric field force. According to the results of electric field force at different expansion conditions, with the increase in temperature, due to expansion of the water tree branches, the electric field force at water tree tips drops, which can suppress the water tree propagation. Regardless of high temperature or low temperature, the water tree propagation is closely related to the mechanical behaviors of the material. With the increase in temperature, the increased deformation will suppress the water tree propagation, whereas the decreased yield strength will promote water tree propagation. For this reason, at different temperatures, the promotion or suppression in water tree propagation is determined by who plays a dominant role.
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