Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535713
A. Subramaniam, P. Mukherjee, Sai Srinivas Manohar, Saniib Kumar Panda
Monitoring transformers is essential to ensure reliable operation of a power system as they are possibly the most critical equipment present in all generation, transmission, and distribution network. Having such monitoring amenable for online implementation is even more desirable. Mechanical deformations are difficult to detect with existing online condition monitoring tools as they hardly lead to any perceivable change in quantities that can be measured from terminals. Leakage flux, amongst all the power frequency parameters, is the most sensitive to changes in winding geometry. Understanding how the spatial distribution of leakage flux is altered by winding deformation would help in diagnosing such damages, preferably at their infancy, by means of flux sensors mounted along the axial height of a winding. As a preliminary study, only axial movements in the winding are considered in this paper. A Finite Element model was developed in Ansys Maxwell to emulate various degrees of axial movement at different places in the winding. The aspects of leakage flux based online winding damage diagnosis at their incipient stage, are investigated in detail with the computed leakage flux distribution and their results presented.
{"title":"Diagnosing Axial Movements in Transformer Windings by Leakage Flux Monitoring","authors":"A. Subramaniam, P. Mukherjee, Sai Srinivas Manohar, Saniib Kumar Panda","doi":"10.1109/CMD.2018.8535713","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535713","url":null,"abstract":"Monitoring transformers is essential to ensure reliable operation of a power system as they are possibly the most critical equipment present in all generation, transmission, and distribution network. Having such monitoring amenable for online implementation is even more desirable. Mechanical deformations are difficult to detect with existing online condition monitoring tools as they hardly lead to any perceivable change in quantities that can be measured from terminals. Leakage flux, amongst all the power frequency parameters, is the most sensitive to changes in winding geometry. Understanding how the spatial distribution of leakage flux is altered by winding deformation would help in diagnosing such damages, preferably at their infancy, by means of flux sensors mounted along the axial height of a winding. As a preliminary study, only axial movements in the winding are considered in this paper. A Finite Element model was developed in Ansys Maxwell to emulate various degrees of axial movement at different places in the winding. The aspects of leakage flux based online winding damage diagnosis at their incipient stage, are investigated in detail with the computed leakage flux distribution and their results presented.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"21 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79830797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535989
Hiromasa Yoshizumi, Y. Nakano, M. Kozako, M. Hikita, Yuuki Fujii, Yusuke Nakamura, Hiroaki Cho
Transient earth voltage (TEV) detection method is drawing attention for its readiness to be installed just on the outer wall of existing equipment, and is useful for partial discharge (PD) detection. The purpose of this research is to establish reliable insulation diagnosis technique of high voltage equipment based on partial discharge detection using TEV method. Our previous study showed that TEV sensor dominantly detects high (several 100 MHz) and low frequency (several 10 MHz) components attributed to the electromagnetic wave propagating through space and discharge current flowing through the ground line, respectively. To investigate a mechanism of generated low frequency components further, this paper deals with the effect of the length of PD measurement circuit on the low frequency component detected by TEV sensor by experiments and simulation of electromagnetic wave propagation using finite difference time domain (FDTD) method. As a result, it was found that the low frequency component includes two different kinds of dominant resonance frequencies determined by assuming the measurement circuit to act as a lumped constant electric circuit and as an antenna such as dipole antenna and loop antenna.
{"title":"Consideration of Generation Mechanism of Low Frequency Component of Partial Discharge Signal Detected by Transient Earth Voltage","authors":"Hiromasa Yoshizumi, Y. Nakano, M. Kozako, M. Hikita, Yuuki Fujii, Yusuke Nakamura, Hiroaki Cho","doi":"10.1109/CMD.2018.8535989","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535989","url":null,"abstract":"Transient earth voltage (TEV) detection method is drawing attention for its readiness to be installed just on the outer wall of existing equipment, and is useful for partial discharge (PD) detection. The purpose of this research is to establish reliable insulation diagnosis technique of high voltage equipment based on partial discharge detection using TEV method. Our previous study showed that TEV sensor dominantly detects high (several 100 MHz) and low frequency (several 10 MHz) components attributed to the electromagnetic wave propagating through space and discharge current flowing through the ground line, respectively. To investigate a mechanism of generated low frequency components further, this paper deals with the effect of the length of PD measurement circuit on the low frequency component detected by TEV sensor by experiments and simulation of electromagnetic wave propagation using finite difference time domain (FDTD) method. As a result, it was found that the low frequency component includes two different kinds of dominant resonance frequencies determined by assuming the measurement circuit to act as a lumped constant electric circuit and as an antenna such as dipole antenna and loop antenna.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"109 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76552383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535618
Md Liton Hossain, A. Abu‐Siada, S. Muyeen
Multilevel power inverter has brought tremendous revolution in high-power medium voltage industrial drive applications due to their superior performance compared to conventional inverters. This paper proposes a hybrid multilevel power electronic inverter (HMPEI) which comprises only one DC source and less number of clamping diodes. Simulation analyses are conducted using MATLAB software to investigate the robustness of the inverter. On the other hand, number of faults are frequently occurring in the inverter leading to adverse impacts on the reliability of the inverter and increasing the system maintenance and operational cost. Condition monitoring plays a vital role to ensure the reliability of the power electronic inverters through detecting incipient faults and rectify them before progression. There are a number of condition monitoring and fault diagnosis techniques to ensure the reliability of the inverter. Electrical signal based condition monitoring is one of the dominating techniques that is widely used to monitor the condition of power electronic inverters because it is easy to implement, cost effective, non-intrusive, able to detect early stage faults, fault location and mode. In this paper, electrical signals are employed to monitor and identify the fault locations in the proposed HMPEI.
{"title":"A Hybrid Multilevel Power Electronic Inverter and Fault Location Identification of Switching Devices","authors":"Md Liton Hossain, A. Abu‐Siada, S. Muyeen","doi":"10.1109/CMD.2018.8535618","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535618","url":null,"abstract":"Multilevel power inverter has brought tremendous revolution in high-power medium voltage industrial drive applications due to their superior performance compared to conventional inverters. This paper proposes a hybrid multilevel power electronic inverter (HMPEI) which comprises only one DC source and less number of clamping diodes. Simulation analyses are conducted using MATLAB software to investigate the robustness of the inverter. On the other hand, number of faults are frequently occurring in the inverter leading to adverse impacts on the reliability of the inverter and increasing the system maintenance and operational cost. Condition monitoring plays a vital role to ensure the reliability of the power electronic inverters through detecting incipient faults and rectify them before progression. There are a number of condition monitoring and fault diagnosis techniques to ensure the reliability of the inverter. Electrical signal based condition monitoring is one of the dominating techniques that is widely used to monitor the condition of power electronic inverters because it is easy to implement, cost effective, non-intrusive, able to detect early stage faults, fault location and mode. In this paper, electrical signals are employed to monitor and identify the fault locations in the proposed HMPEI.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"30 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87834118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535693
N. Muhamad, N. A. Rahim, Saiful Mohammad Iezham Suhaimi, N. Bashir, N. A. Ahmad
Surface discharges are precursors to flashovers. To pre-empt the occurrence of flashover incidents, utility companies need to regularly monitor the condition of line insulators. Recent studies have shown that monitoring of ultra-violet (UV) signals emitted by surface discharges of the insulators is a promising technique. In this study, set of contaminated and aged insulator was used. UV pulse signal of surface discharges activities on these insulators was recorded and analyzed. Experimental result showed that a strong correlation exists between the discharge intensity levels under varying contamination levels and degree of ageing. As the contamination level increased, the discharge levels of the insulator samples intensified, resulting in the increase of total harmonic distortion (THD). THD of the UV signals have been employed by using MATLAB simulation to develop a technique based on artificial neural network (ANN) to classify the flashover prediction based on the discharge intensity levels of the insulator samples. The results of the ANN simulation showed 87% accuracy in the performance index. This study illustrates that UV pulse detection method can be a potential tool to monitor insulator surface conditions during service.
{"title":"Detection of Transmission Line Insulator Flashover Based on Categorized Discharge Intensity Level of Ultravoilet Signal","authors":"N. Muhamad, N. A. Rahim, Saiful Mohammad Iezham Suhaimi, N. Bashir, N. A. Ahmad","doi":"10.1109/CMD.2018.8535693","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535693","url":null,"abstract":"Surface discharges are precursors to flashovers. To pre-empt the occurrence of flashover incidents, utility companies need to regularly monitor the condition of line insulators. Recent studies have shown that monitoring of ultra-violet (UV) signals emitted by surface discharges of the insulators is a promising technique. In this study, set of contaminated and aged insulator was used. UV pulse signal of surface discharges activities on these insulators was recorded and analyzed. Experimental result showed that a strong correlation exists between the discharge intensity levels under varying contamination levels and degree of ageing. As the contamination level increased, the discharge levels of the insulator samples intensified, resulting in the increase of total harmonic distortion (THD). THD of the UV signals have been employed by using MATLAB simulation to develop a technique based on artificial neural network (ANN) to classify the flashover prediction based on the discharge intensity levels of the insulator samples. The results of the ANN simulation showed 87% accuracy in the performance index. This study illustrates that UV pulse detection method can be a potential tool to monitor insulator surface conditions during service.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"14 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88982006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535786
Yuwei Fu, Xiaohua Wang, A. Yang, Jiandong Duan
SF6 has been widely used as insulating and arc-extinguishing medium in power equipment. But under arc discharges, lower fluorides of sulfur (like SF5, SF4and SF3) generated by the dissociations of SF6will react with unavoidable atoms (like O and H) released from trace impurities of moisture to form corrosive byproducts such as SOF2, SO2F2, SOF4and so on. These byproducts will reduce the insulating and arc-quenching capacity of SF6-insulated power equipment, so it is necessary to study the compositions of decaying SF6arc plasma in the presence of H2O. In this paper, both non-chemical and non-thermodynamic equilibriums are taken into consideration employing chemical kinetic model. The elementary reactions of SF6with H2O are determined by density functional theory and the rate coefficients are computed with transition state theory. Then we calculated the temperature-varying molar fractions of main byproducts SOF2, SO2F2and SOF4under different contents of H2O. We also analyzed the dominant reactions in different selected temperature ranges. This work can lay a theoretical basis for insulating condition monitoring and diagnosis of SF6-insulated power equipment based on characteristic decomposition products.
{"title":"Compositions of SF6 - H2O Decaying Arc at a Temperature Range of 1000–12000 K","authors":"Yuwei Fu, Xiaohua Wang, A. Yang, Jiandong Duan","doi":"10.1109/CMD.2018.8535786","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535786","url":null,"abstract":"SF<inf>6</inf> has been widely used as insulating and arc-extinguishing medium in power equipment. But under arc discharges, lower fluorides of sulfur (like SF<inf>5</inf>, SF<inf>4</inf>and SF3) generated by the dissociations of SF<inf>6</inf>will react with unavoidable atoms (like O and H) released from trace impurities of moisture to form corrosive byproducts such as SOF<inf>2</inf>, SO<inf>2</inf>F<inf>2</inf>, SOF<inf>4</inf>and so on. These byproducts will reduce the insulating and arc-quenching capacity of SF<inf>6</inf>-insulated power equipment, so it is necessary to study the compositions of decaying SF<inf>6</inf>arc plasma in the presence of H<inf>2</inf>O. In this paper, both non-chemical and non-thermodynamic equilibriums are taken into consideration employing chemical kinetic model. The elementary reactions of SF<inf>6</inf>with H<inf>2</inf>O are determined by density functional theory and the rate coefficients are computed with transition state theory. Then we calculated the temperature-varying molar fractions of main byproducts SOF<inf>2</inf>, SO<inf>2</inf>F<inf>2</inf>and SOF<inf>4</inf>under different contents of H<inf>2</inf>O. We also analyzed the dominant reactions in different selected temperature ranges. This work can lay a theoretical basis for insulating condition monitoring and diagnosis of SF<inf>6</inf>-insulated power equipment based on characteristic decomposition products.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"12 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82019091","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535801
Ke Wang, Xiaoming Mai, Jin Tan, Yue Hu, Hongyi Huang
The omnidirectional antenna mounted on the substation inspection robot is an important device for PD detection in substation. In addition to the requirements such as wide operating frequency band, directional pattern covering detecting area and large gain, this antenna must also consider the requirements of practical application circumstance. On the one hand, the fact that antenna is operated on a mobile robot gives the requirements about the size and weight of the antenna. On the other hand, type selecting and parameters adjusting of antenna must consider the effects on antenna performance caused by the metallic environment of installation position. This paper designed and optimized a dual polarized planar antenna with the inverted-cone structure based on the requirements of PD detecting omnidirectional antenna in substation. In the bottom half of the antenna, cross - orthogonal trapezoidal plates are used to build up the inverted-cone structure to achieve the “up-warp” in the antenna E-plane radiation pattern, and the size of the bottom of the antenna is reduced by using a bottom circular plate with the outward-dipping edge. It can receive the PD electromagnetic wave signal sensitively, which meets the design requirements of the installation circumstance on inspection robot and PD detection in the entire substation.
{"title":"Design of an omnidirectional PD UHF antenna for substation inspection robot considering installation circumstance","authors":"Ke Wang, Xiaoming Mai, Jin Tan, Yue Hu, Hongyi Huang","doi":"10.1109/CMD.2018.8535801","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535801","url":null,"abstract":"The omnidirectional antenna mounted on the substation inspection robot is an important device for PD detection in substation. In addition to the requirements such as wide operating frequency band, directional pattern covering detecting area and large gain, this antenna must also consider the requirements of practical application circumstance. On the one hand, the fact that antenna is operated on a mobile robot gives the requirements about the size and weight of the antenna. On the other hand, type selecting and parameters adjusting of antenna must consider the effects on antenna performance caused by the metallic environment of installation position. This paper designed and optimized a dual polarized planar antenna with the inverted-cone structure based on the requirements of PD detecting omnidirectional antenna in substation. In the bottom half of the antenna, cross - orthogonal trapezoidal plates are used to build up the inverted-cone structure to achieve the “up-warp” in the antenna E-plane radiation pattern, and the size of the bottom of the antenna is reduced by using a bottom circular plate with the outward-dipping edge. It can receive the PD electromagnetic wave signal sensitively, which meets the design requirements of the installation circumstance on inspection robot and PD detection in the entire substation.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"55 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90832131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535827
Jindun Dai, Yadong Liu, Jin He, X. Mao, G. Sheng, Xiuchen Jiang
Multi-sensor image fusion leads to more abundant details and a better description of the electric equipment monitoring scene. To improve the accuracy of overheating fault localization, a novel image fusion method based on Finite Discrete Shearlet Transform (FDST) and Dual-Channel Pulse Coupled Neuron Network (DC-PCNN) is proposed for fusing infrared and visible images of electric equipment. Firstly, FDST is utilized to decompose the source images. Then, two modified-spatial-frequency motivated DC-PCNNs with different linking strengths are used to fuse low-frequency and high-frequency subbands. Finally, the final fused image is reconstructed from the fused subbands by inverse FDST. Experimental results demonstrate the proposed method can achieve a remarkable improvement in preserving detail information and outperform other typical fusion methods in both overall visual performance and objective criteria.
{"title":"Infrared and Visible Image Fusion of Electric Equipment Using FDST and DC-PCNN","authors":"Jindun Dai, Yadong Liu, Jin He, X. Mao, G. Sheng, Xiuchen Jiang","doi":"10.1109/CMD.2018.8535827","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535827","url":null,"abstract":"Multi-sensor image fusion leads to more abundant details and a better description of the electric equipment monitoring scene. To improve the accuracy of overheating fault localization, a novel image fusion method based on Finite Discrete Shearlet Transform (FDST) and Dual-Channel Pulse Coupled Neuron Network (DC-PCNN) is proposed for fusing infrared and visible images of electric equipment. Firstly, FDST is utilized to decompose the source images. Then, two modified-spatial-frequency motivated DC-PCNNs with different linking strengths are used to fuse low-frequency and high-frequency subbands. Finally, the final fused image is reconstructed from the fused subbands by inverse FDST. Experimental results demonstrate the proposed method can achieve a remarkable improvement in preserving detail information and outperform other typical fusion methods in both overall visual performance and objective criteria.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"4 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90199944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Partial Discharge(PD) can be located by using algorithms based on Time Difference of Arriving signals (TDOA). A novel grid searching method in spherical coordinate system is proposed to further foster its strengthens in raise angle location, which is theoretically analyzed that grid searching method can locate angle of PD with higher resolution than distance, and circumvent its weakness in high computational cost. In this paper, the detailed location process of this novel algorithm is described and simulations are carried out to verify effectiveness of proposed method. The principle of accurate angular positioning is introduced in detail, and the simulation of different delay errors and grid division is carried out. It is found that the positioning accuracy decreases with the increase of delay error. Compared with cartesian coordinate system, the angular orientation in spherical coordinate system is more accurate and the calculation quantity is lower. The optimal grid partition parameters are given. Application example in a substation also shows the high reliability in angle location and practicability
{"title":"Grid searching method in spherical coordinate for PD location in a substation","authors":"F. Xue, Dongliang Wei, Zhi Wang, Tong Li, Yue Hu, Hongyi Huang","doi":"10.1109/CMD.2018.8535972","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535972","url":null,"abstract":"Partial Discharge(PD) can be located by using algorithms based on Time Difference of Arriving signals (TDOA). A novel grid searching method in spherical coordinate system is proposed to further foster its strengthens in raise angle location, which is theoretically analyzed that grid searching method can locate angle of PD with higher resolution than distance, and circumvent its weakness in high computational cost. In this paper, the detailed location process of this novel algorithm is described and simulations are carried out to verify effectiveness of proposed method. The principle of accurate angular positioning is introduced in detail, and the simulation of different delay errors and grid division is carried out. It is found that the positioning accuracy decreases with the increase of delay error. Compared with cartesian coordinate system, the angular orientation in spherical coordinate system is more accurate and the calculation quantity is lower. The optimal grid partition parameters are given. Application example in a substation also shows the high reliability in angle location and practicability","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"25 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78228613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535676
Yandong Li, Hongyi Huang, Yue Hu, Weidong Zhang
Partial Discharge (PD) is a localized dielectric breakdown of electric insulation system, the detection of such phenomenon plays an important role in insulator maintenance. Among various kinds of PD, surface discharge is a typical one that must be studied to obtain its characteristics information and then be further distinguished from different types of PD. The microscopic process of particle movement is simulated in this paper by combing particle in cell (PIC) method with Monte Carlo collision (MCC) method, which possesses great significance for researching the practical mechanism of partial discharge. The principle of PIC-MCC method is described in this paper and the simulations are carried out to show detailed microscopic process and obtain PD current for macro characteristics analysis. PD current pulse waveform of surface discharge is analyzed and compared with the waveforms of point discharge and void discharge. The effects of voltage difference and physical model shape on PD characteristics are also discussed in this paper.
{"title":"Microscopic simulation and characteristics analysis of surface discharge based on PIC-MCC method","authors":"Yandong Li, Hongyi Huang, Yue Hu, Weidong Zhang","doi":"10.1109/CMD.2018.8535676","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535676","url":null,"abstract":"Partial Discharge (PD) is a localized dielectric breakdown of electric insulation system, the detection of such phenomenon plays an important role in insulator maintenance. Among various kinds of PD, surface discharge is a typical one that must be studied to obtain its characteristics information and then be further distinguished from different types of PD. The microscopic process of particle movement is simulated in this paper by combing particle in cell (PIC) method with Monte Carlo collision (MCC) method, which possesses great significance for researching the practical mechanism of partial discharge. The principle of PIC-MCC method is described in this paper and the simulations are carried out to show detailed microscopic process and obtain PD current for macro characteristics analysis. PD current pulse waveform of surface discharge is analyzed and compared with the waveforms of point discharge and void discharge. The effects of voltage difference and physical model shape on PD characteristics are also discussed in this paper.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"25 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74990289","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-09-01DOI: 10.1109/CMD.2018.8535770
H. Morooka, A. Yamagishi, K. Kawamura, H. Kojima, N. Hayakawa
The effects of thermal degradation and aging on the properties of mineral-oil-immersed pressboards (PBs) were studied from the viewpoint of diagnosis of power transformers. Specifically, thickness, degree of polymerization (DP), and compressive properties of oil-immersed PBs after heat-accelerated degradation in sealed containers were evaluated. The degree of crystallization (Cr) of oil-immersed PBs was then evaluated by X-ray diffraction (XRD). The evaluation results revealed that after thermal aging, DP decreased. Moreover, thickness, compressive elasticity modulus, and hysteresis loss ratio slightly decreased. Conversely, Cr slightly increased. DP of kraft paper is known to decrease after aging. Simultaneously, several compounds with low molecular weight, such as CO, CO2, and furfurals, are generated, and the tensile strength of kraft paper decreases. It is therefore assumed here that the thickness of PBs decreases very little as they generate low-molecular-weight decomposition compounds and that the decrease in DP causes a slight decrease in the compressive elasticity modulus, E. However, an increase in Cr causes a slight increase in E. As a result, the overall decrease in E is slight.
{"title":"Thermal-degradation Mechanism of Mineral-oil-immersed Pressboards and Influence of Aging on Pressboard Properties","authors":"H. Morooka, A. Yamagishi, K. Kawamura, H. Kojima, N. Hayakawa","doi":"10.1109/CMD.2018.8535770","DOIUrl":"https://doi.org/10.1109/CMD.2018.8535770","url":null,"abstract":"The effects of thermal degradation and aging on the properties of mineral-oil-immersed pressboards (PBs) were studied from the viewpoint of diagnosis of power transformers. Specifically, thickness, degree of polymerization (DP), and compressive properties of oil-immersed PBs after heat-accelerated degradation in sealed containers were evaluated. The degree of crystallization (Cr) of oil-immersed PBs was then evaluated by X-ray diffraction (XRD). The evaluation results revealed that after thermal aging, DP decreased. Moreover, thickness, compressive elasticity modulus, and hysteresis loss ratio slightly decreased. Conversely, Cr slightly increased. DP of kraft paper is known to decrease after aging. Simultaneously, several compounds with low molecular weight, such as CO, CO2, and furfurals, are generated, and the tensile strength of kraft paper decreases. It is therefore assumed here that the thickness of PBs decreases very little as they generate low-molecular-weight decomposition compounds and that the decrease in DP causes a slight decrease in the compressive elasticity modulus, E. However, an increase in Cr causes a slight increase in E. As a result, the overall decrease in E is slight.","PeriodicalId":6529,"journal":{"name":"2018 Condition Monitoring and Diagnosis (CMD)","volume":"18 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2018-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73633163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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