To address harmonic current proliferation and parameter sensitivity in conventional vector model predictive control (V-MPC) for dual-three-phase permanent magnet synchronous generators (DTP-PMSGs), a harmonic subspace-incorporated disturbance-rejection MPC strategy is proposed. First, an enhanced virtual voltage vector synthesis technique is developed in which three optimal voltage vectors per control sector are strategically combined to achieve full-amplitude and omnidirectional voltage coverage, eliminating harmonic subspace excitation. Second, a super-twisting integral disturbance observer is designed to dynamically estimate and compensate for parameter mismatches and nonlinear rectification disturbances, thereby enhancing the robustness against model inaccuracies. Third, a composite harmonic suppression controller is proposed to replace traditional PI regulators, enabling zero-steady-state error tracking of fundamental currents while actively attenuating harmonic subspace components. Experimental validations confirm that the proposed methodology improves the fundamental current-tracking accuracy, significantly suppresses harmonic currents, and maintains a robust dynamic response under parameter variations.
{"title":"Disturbance-Rejection Model Predictive Current Control for Dual-Three-Phase Permanent Magnet Synchronous Generators with Harmonic Subspace Consideration","authors":"Zhengqi Wang;Jun Huo;Wenxiang Zhao;Qiang Zhang;Hao Chang","doi":"10.23919/CJEE.2025.000171","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000171","url":null,"abstract":"To address harmonic current proliferation and parameter sensitivity in conventional vector model predictive control (V-MPC) for dual-three-phase permanent magnet synchronous generators (DTP-PMSGs), a harmonic subspace-incorporated disturbance-rejection MPC strategy is proposed. First, an enhanced virtual voltage vector synthesis technique is developed in which three optimal voltage vectors per control sector are strategically combined to achieve full-amplitude and omnidirectional voltage coverage, eliminating harmonic subspace excitation. Second, a super-twisting integral disturbance observer is designed to dynamically estimate and compensate for parameter mismatches and nonlinear rectification disturbances, thereby enhancing the robustness against model inaccuracies. Third, a composite harmonic suppression controller is proposed to replace traditional PI regulators, enabling zero-steady-state error tracking of fundamental currents while actively attenuating harmonic subspace components. Experimental validations confirm that the proposed methodology improves the fundamental current-tracking accuracy, significantly suppresses harmonic currents, and maintains a robust dynamic response under parameter variations.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 4","pages":"227-242"},"PeriodicalIF":3.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11176939","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915602","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Accurately predicting photovoltaic (PV) power generation is essential for effective power system scheduling. However, increased incidences of sandy weather in recent years pose significant challenges for PV power plants in desert regions. This study addresses the inaccuracies in PV power forecasting under windy-sandy conditions by conducting wind tunnel experiments to evaluate the impact of varying wind speeds and PV panel tilt angles on power generation. Polynomial equations are developed through polynomial surface fitting to establish a relationship between the power loss rate, sand-blowing wind speed, and panel tilt angle. Latin hypercube sampling is used to extend the fitted surface scenarios, simulating real-world variations in PV power generation to enhance the accuracy and applicability of the model. In addition, the model incorporates three uncertainties related to wind direction, module aging, and airflow effects on PV arrays. A case study utilizing data from a PV power plant employs the Pseudo-similar day selection method, enabling a comparative analysis of the predicted outcomes with traditional methodologies. This comparison demonstrates the accuracy and effectiveness of the proposed method for improving PV power prediction under challenging conditions.
{"title":"Output Prediction of Photovoltaic Power Generation System with Multiple Uncertainties in Windy/Sandy Weather","authors":"Siyu Chen;Shuaibing Li;Junxia Jiang;Jiuding Tan;Haiying Dong","doi":"10.23919/CJEE.2025.000116","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000116","url":null,"abstract":"Accurately predicting photovoltaic (PV) power generation is essential for effective power system scheduling. However, increased incidences of sandy weather in recent years pose significant challenges for PV power plants in desert regions. This study addresses the inaccuracies in PV power forecasting under windy-sandy conditions by conducting wind tunnel experiments to evaluate the impact of varying wind speeds and PV panel tilt angles on power generation. Polynomial equations are developed through polynomial surface fitting to establish a relationship between the power loss rate, sand-blowing wind speed, and panel tilt angle. Latin hypercube sampling is used to extend the fitted surface scenarios, simulating real-world variations in PV power generation to enhance the accuracy and applicability of the model. In addition, the model incorporates three uncertainties related to wind direction, module aging, and airflow effects on PV arrays. A case study utilizing data from a PV power plant employs the Pseudo-similar day selection method, enabling a comparative analysis of the predicted outcomes with traditional methodologies. This comparison demonstrates the accuracy and effectiveness of the proposed method for improving PV power prediction under challenging conditions.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"113-126"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207217","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.23919/CJEE.2025.000148
Ahmed Lashin;Abdelhady Ghanem;Sahar S. Kaddah;Weihao Hu;Fujin Deng;Sayed Abulanwar
The utilization of renewable energy resources (RERs) in microgrids (MGs) has increased significantly in recent years, especially for standalone applications with techno-economic purposes. However, the wide diversification and the stochastic nature of RERs introduces substantial challenges for MG operation and energy exchange under various operational modes. A multimode adaptive droop-based distributed energy management strategy is proposed for a hybrid AC/DC microgrid, incorporating a congregated energy storage system (CESS) to overcome issues associated with distributed counterpart. The MG is fed by wind and solar energy, supported by a CESS comprising supercapacitor stacks, batteries, and a hydrogen management system, to foster reliable power delivery irrespective of RERs fluctuations. The suggested strategy allocates the battery state of charge and supercapacitor voltage to designate operational modes, considering the readiness and constraints of each source and storage unit. The primary objective is to stabilize the DC bus voltage and regulate the point of common coupling voltage and frequency during any conceivable mode. Furthermore, an efficient battery energy storage controller is proposed and adaptively regulated during charging and discharging to avoid battery over-charging and over-discharging. Case studies validate the performance of the proposed scheme across all operational modes, revealing superior performance without reliance on communication links.
{"title":"Adaptive Multimode Droop-Based Distributed Energy Management for Standalone Hybrid AC/DC Microgrid","authors":"Ahmed Lashin;Abdelhady Ghanem;Sahar S. Kaddah;Weihao Hu;Fujin Deng;Sayed Abulanwar","doi":"10.23919/CJEE.2025.000148","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000148","url":null,"abstract":"The utilization of renewable energy resources (RERs) in microgrids (MGs) has increased significantly in recent years, especially for standalone applications with techno-economic purposes. However, the wide diversification and the stochastic nature of RERs introduces substantial challenges for MG operation and energy exchange under various operational modes. A multimode adaptive droop-based distributed energy management strategy is proposed for a hybrid AC/DC microgrid, incorporating a congregated energy storage system (CESS) to overcome issues associated with distributed counterpart. The MG is fed by wind and solar energy, supported by a CESS comprising supercapacitor stacks, batteries, and a hydrogen management system, to foster reliable power delivery irrespective of RERs fluctuations. The suggested strategy allocates the battery state of charge and supercapacitor voltage to designate operational modes, considering the readiness and constraints of each source and storage unit. The primary objective is to stabilize the DC bus voltage and regulate the point of common coupling voltage and frequency during any conceivable mode. Furthermore, an efficient battery energy storage controller is proposed and adaptively regulated during charging and discharging to avoid battery over-charging and over-discharging. Case studies validate the performance of the proposed scheme across all operational modes, revealing superior performance without reliance on communication links.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"146-166"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207220","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
New energy-vehicle charging and discharging units in vehicle to grid (V2G) application scenarios experience long and large transient fluctuations in power and frequency at their power injection points. Furthermore, the power matching degree is low, which has a serious impact on the V2G support performance. This paper proposes a two-step model prediction-virtual synchronous machine (MPC-VSG) control strategy that considers the SOC of the charging and discharging unit. First, the VSG equivalent model of the V2G grid-connected inverter is established, and the power weight coefficients of the charging and discharging unit SOC participating in frequency regulation are obtained by analyzing its characteristics. Second, the power change prediction value is obtained from the VSG model, and the two-step prediction of the reference frequency is performed to reduce the error of the reference value remaining unchanged at the instant of sudden power change. Minimizing the sum of squares of real-time output power deviations and frequency fluctuations as a cost function to compensate for the optimal active losses and suppress the frequency transient fluctuations. Finally, simulation analysis is carried out under the working conditions of island mode operation, V2G grid-connected operation, and wind power multi-energy complementary operation, and an experimental verification of the inverter part is carried out to verify the effectiveness and superiority of the proposed control strategy.
{"title":"Optimal Control Strategy for Frequency Response of V2G Grid-Connected Inverter Considering SOC Characteristics","authors":"Peijin Liu;Zhengming Feng;Ping Wei;Hongxian Li;Qianjun Liu;Yong Chen","doi":"10.23919/CJEE.2025.000169","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000169","url":null,"abstract":"New energy-vehicle charging and discharging units in vehicle to grid (V2G) application scenarios experience long and large transient fluctuations in power and frequency at their power injection points. Furthermore, the power matching degree is low, which has a serious impact on the V2G support performance. This paper proposes a two-step model prediction-virtual synchronous machine (MPC-VSG) control strategy that considers the SOC of the charging and discharging unit. First, the VSG equivalent model of the V2G grid-connected inverter is established, and the power weight coefficients of the charging and discharging unit SOC participating in frequency regulation are obtained by analyzing its characteristics. Second, the power change prediction value is obtained from the VSG model, and the two-step prediction of the reference frequency is performed to reduce the error of the reference value remaining unchanged at the instant of sudden power change. Minimizing the sum of squares of real-time output power deviations and frequency fluctuations as a cost function to compensate for the optimal active losses and suppress the frequency transient fluctuations. Finally, simulation analysis is carried out under the working conditions of island mode operation, V2G grid-connected operation, and wind power multi-energy complementary operation, and an experimental verification of the inverter part is carried out to verify the effectiveness and superiority of the proposed control strategy.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"127-145"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207221","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.23919/CJEE.2025.000170
Xinyu Wang;Jiawang He;Yongjun Li;Yongsen Han
Nonlinear conductivity enables an insulating material to self-homogenize its electric field distribution, which can be regulated by the core-shell method. In this study, the effects of SiC@A12O3 on nonlinear conductivity are investigated. First, SiC@A12O3 nanoparticles are fabricated. Subsequently, 3 wt%, 7 wt%, and 10 wt% SiC@A12O3/epoxy and SiC/epoxy composites are prepared. The microstructures of the SiC@A12O3 nanoparticles are characterized using transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The dielectric spectra, breakdown strengths, and conductivities of the epoxy composites are investigated. The experimental results show that a 2-nm-thickness Al2O3 shell is formed around the SiC nanoparticles. Compared with the raw SiC nanoparticles, the SiC@Al2O3 nanoparticles not only reduced the relative permittivity and loss tangent of the composite but also enhanced its breakdown strength. All of the SiC/epoxy composites exhibited nonlinear conductivity, whereas only the 7 wt% and 10 wt% SiC@Al2O3/epoxy composites exhibited nonlinear conductivity. Moreover, the SiC@Al2O3/epoxy composites had a higher switching electric field (i.e., the initial electric field for nonlinear conductivity) than the SiC/epoxy composites. The results demonstrate the possibility of using nonlinear resistive field grading material in high-electric-field applications.
{"title":"Effects of SiC@Al2O3 Nanoparticles on the Nonlinear Conductivity of Epoxy Composites","authors":"Xinyu Wang;Jiawang He;Yongjun Li;Yongsen Han","doi":"10.23919/CJEE.2025.000170","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000170","url":null,"abstract":"Nonlinear conductivity enables an insulating material to self-homogenize its electric field distribution, which can be regulated by the core-shell method. In this study, the effects of SiC@A1<inf>2</inf>O<inf>3</inf> on nonlinear conductivity are investigated. First, SiC@A1<inf>2</inf>O<inf>3</inf> nanoparticles are fabricated. Subsequently, 3 wt%, 7 wt%, and 10 wt% SiC@A1<inf>2</inf>O<inf>3</inf>/epoxy and SiC/epoxy composites are prepared. The microstructures of the SiC@A1<inf>2</inf>O<inf>3</inf> nanoparticles are characterized using transmission electron microscopy, scanning electron microscopy, and X-ray diffraction. The dielectric spectra, breakdown strengths, and conductivities of the epoxy composites are investigated. The experimental results show that a 2-nm-thickness Al<inf>2</inf>O<inf>3</inf> shell is formed around the SiC nanoparticles. Compared with the raw SiC nanoparticles, the SiC@Al<inf>2</inf>O<inf>3</inf> nanoparticles not only reduced the relative permittivity and loss tangent of the composite but also enhanced its breakdown strength. All of the SiC/epoxy composites exhibited nonlinear conductivity, whereas only the 7 wt% and 10 wt% SiC@Al<inf>2</inf>O<inf>3</inf>/epoxy composites exhibited nonlinear conductivity. Moreover, the SiC@Al<inf>2</inf>O<inf>3</inf>/epoxy composites had a higher switching electric field (i.e., the initial electric field for nonlinear conductivity) than the SiC/epoxy composites. The results demonstrate the possibility of using nonlinear resistive field grading material in high-electric-field applications.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"29-37"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207163","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.23919/CJEE.2025.000158
Haosen Du;Yasuhiro Tanaka;Hiroaki Miyake
Epoxy resin is widely used in high-temperature, high-electric-field power equipment owing to its stable physicochemical properties and excellent insulation performance. During prolonged operation, it undergoes thermal aging, making lifetime extension essential. The effects of thermal aging on insulation by comparing samples cured with anhydride curing agents under both air and non-air conditions are investigated. The Fourier transform infrared spectroscopy, current integrated charge, and pulsed electro-acoustic methods are used to analyze physicochemical characteristics and electrical performance. Control groups compared thermal aging in air versus an oil bath to examine atmospheric influences. Results show that air-aged samples turned yellow, while the oil bath-aged samples remained colorless. At temperatures above $T_{mathrm{g}}$(135°C), air-aged samples showed more positive hetero charge accumulation. Non-air-aged samples also accumulated space charge, but to a lesser extent, and showed better insulation breakdown resistance. These findings indicate that thermal aging in air may degrade insulation performance owing to oxidative effects.
{"title":"Estimation of Insulating Performance Degradation in Anhydride-Cured Epoxy Resin by Thermal Aging Using Current Integrated Charge Method","authors":"Haosen Du;Yasuhiro Tanaka;Hiroaki Miyake","doi":"10.23919/CJEE.2025.000158","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000158","url":null,"abstract":"Epoxy resin is widely used in high-temperature, high-electric-field power equipment owing to its stable physicochemical properties and excellent insulation performance. During prolonged operation, it undergoes thermal aging, making lifetime extension essential. The effects of thermal aging on insulation by comparing samples cured with anhydride curing agents under both air and non-air conditions are investigated. The Fourier transform infrared spectroscopy, current integrated charge, and pulsed electro-acoustic methods are used to analyze physicochemical characteristics and electrical performance. Control groups compared thermal aging in air versus an oil bath to examine atmospheric influences. Results show that air-aged samples turned yellow, while the oil bath-aged samples remained colorless. At temperatures above <tex>$T_{mathrm{g}}$</tex>(135°C), air-aged samples showed more positive hetero charge accumulation. Non-air-aged samples also accumulated space charge, but to a lesser extent, and showed better insulation breakdown resistance. These findings indicate that thermal aging in air may degrade insulation performance owing to oxidative effects.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"47-59"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207161","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145351927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the application of communication network technology in power systems, traditional power grids have gradually developed into cyber-physical systems (CPS), and false data injection (FDI) attacks have become a hidden danger that affects the operation of power CPS. To solve the problems of low estimation accuracy and model uncertainty when the extended Kalman filter (EKF) algorithm is subjected to FDI attacks in power systems, an interpolation adaptive $mathrm{H}_{infty}$ extended Kalman filter (IAHEKF) algorithm is proposed for the dynamic state estimation of power systems under FDI attacks. The new algorithm uses an interpolation strategy to reduce the linearization error of the EKF algorithm and introduces adaptive $mathrm{H}_{infty}$ theory to update the error covariance, minimizing the error upper bound caused by model uncertainty; moreover, it uses the Sage-Husa estimator to calculate the noise covariance, reducing the impact of unknown noise on state estimation. Finally, tests are conducted on the IEEE-14 node system and IEEE-30 node system, and the results show that the IAHEKF algorithm has higher estimation accuracy under different attack scenarios.
{"title":"Dynamic State Estimation of Power System Under FDI Attacks Based on Interpolating AHEKF Algorithm","authors":"Chunling Wu;Kejun Zheng;Zhen Zhang;Yubing Zhao;Jinhao Meng;Hao Chen","doi":"10.23919/CJEE.2025.000107","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000107","url":null,"abstract":"With the application of communication network technology in power systems, traditional power grids have gradually developed into cyber-physical systems (CPS), and false data injection (FDI) attacks have become a hidden danger that affects the operation of power CPS. To solve the problems of low estimation accuracy and model uncertainty when the extended Kalman filter (EKF) algorithm is subjected to FDI attacks in power systems, an interpolation adaptive <tex>$mathrm{H}_{infty}$</tex> extended Kalman filter (IAHEKF) algorithm is proposed for the dynamic state estimation of power systems under FDI attacks. The new algorithm uses an interpolation strategy to reduce the linearization error of the EKF algorithm and introduces adaptive <tex>$mathrm{H}_{infty}$</tex> theory to update the error covariance, minimizing the error upper bound caused by model uncertainty; moreover, it uses the Sage-Husa estimator to calculate the noise covariance, reducing the impact of unknown noise on state estimation. Finally, tests are conducted on the IEEE-14 node system and IEEE-30 node system, and the results show that the IAHEKF algorithm has higher estimation accuracy under different attack scenarios.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"98-112"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207216","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.23919/CJEE.2025.000128
Ahmed S. Haiba
Technological progress has led to the development of high-voltage testing equipment with extremely high-voltage ranges potentially reaching 600 kV or higher. Such equipment cannot be calibrated using portable devices within the same range. Therefore, this study presents an on-site calibration method for high-voltage testing equipment up to 600 kV. A standard divider with a 300 kV range and a high-resolution digital multimeter for leakage current measurements are used for the calibration. To extend the calibration above 300 kV, a scale factor for the impedance method is introduced. The results demonstrate that linearity is achieved at all calibrated points, with a linearity error not exceeding 1%, indicating that the calibration can be extended to 600 kV. The findings also confirm that the unit under calibration complied with its specified accuracy. Additionally, the expanded uncertainty is estimated for each range to assess the reliability of the results. Finally, a comparison and verification tool is introduced using a normalized error tool to ensure the validity of the proposed technique. The normalized error tool results indicate that the proposed method yields satisfactory outcomes. This study establishes an on-site calibration service for high-voltage testing equipment up to 600 kV, extending the previous limit of 300 kV.
{"title":"Implementation and Evaluation of an On-Site Calibration Method for High-Voltage Testing Systems up to 600 kV","authors":"Ahmed S. Haiba","doi":"10.23919/CJEE.2025.000128","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000128","url":null,"abstract":"Technological progress has led to the development of high-voltage testing equipment with extremely high-voltage ranges potentially reaching 600 kV or higher. Such equipment cannot be calibrated using portable devices within the same range. Therefore, this study presents an on-site calibration method for high-voltage testing equipment up to 600 kV. A standard divider with a 300 kV range and a high-resolution digital multimeter for leakage current measurements are used for the calibration. To extend the calibration above 300 kV, a scale factor for the impedance method is introduced. The results demonstrate that linearity is achieved at all calibrated points, with a linearity error not exceeding 1%, indicating that the calibration can be extended to 600 kV. The findings also confirm that the unit under calibration complied with its specified accuracy. Additionally, the expanded uncertainty is estimated for each range to assess the reliability of the results. Finally, a comparison and verification tool is introduced using a normalized error tool to ensure the validity of the proposed technique. The normalized error tool results indicate that the proposed method yields satisfactory outcomes. This study establishes an on-site calibration service for high-voltage testing equipment up to 600 kV, extending the previous limit of 300 kV.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"243-252"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207162","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to measure the space charge of extremely thick insulating systems, such as full-scale ultrahigh-voltage cables and joint boxes, with high accuracy using the pulse electroacoustic method. The proposed method employs an electrically insulating acoustic coupler to improve acoustic matching. Additionally, a metallic backing with high acoustic impedance is applied to upgrade the sensitivity to almost five times that of conventional measuring systems. However, the proposed structure requires an extremely thick backing material to avoid multiple reflections when the specimen thickens. In this study, a backing structure that combines a thin polymer plate with an air layer is proposed. Because multiple reflections are not returned from the air layer, the backing structure can be designed to be extremely small, thereby maintaining high sensitivity. This advantage is verified experimentally.
{"title":"Acoustic Propagation Paths for Space-Charge Measurement in Thick Insulating Materials","authors":"Xiaoxin Li;Yeong-Guk An;Tomohiro Kawashima;Yoshinobu Murakami;Naohiro Hozumi","doi":"10.23919/CJEE.2025.000178","DOIUrl":"https://doi.org/10.23919/CJEE.2025.000178","url":null,"abstract":"This study aims to measure the space charge of extremely thick insulating systems, such as full-scale ultrahigh-voltage cables and joint boxes, with high accuracy using the pulse electroacoustic method. The proposed method employs an electrically insulating acoustic coupler to improve acoustic matching. Additionally, a metallic backing with high acoustic impedance is applied to upgrade the sensitivity to almost five times that of conventional measuring systems. However, the proposed structure requires an extremely thick backing material to avoid multiple reflections when the specimen thickens. In this study, a backing structure that combines a thin polymer plate with an air layer is proposed. Because multiple reflections are not returned from the air layer, the backing structure can be designed to be extremely small, thereby maintaining high sensitivity. This advantage is verified experimentally.","PeriodicalId":36428,"journal":{"name":"Chinese Journal of Electrical Engineering","volume":"11 3","pages":"38-46"},"PeriodicalIF":3.5,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11207167","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145352252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.23919/CJEE.2025.000149
Shu Niu;Shuai Li;Jizhong Liang;Guodong Li;Fan Hu;Hai Zhan;Yujie Zhu;Xianhao Fan;Chuanyang Li
Epoxy resin is widely used in electrical insulation because of its excellent mechanical and insulating properties; however, its performance can degrade over time owing to thermal aging. This study focuses on developing a thermal aging region growth model for epoxy resin using the phase-field method. The reliability of the model is validated by applying a 20 MV/m electric field and observing the evolution of aging regions and the distribution of the internal energy density. A Gaussian-distributed aging region near the electrodes confirmed that the model accurately captured the uniform growth of aging regions under a constant electric field, with thermal energy playing a dominant role in the aging process. To examine the impact of internal defects, a fully aged region is introduced at the center of the simulation domain to simulate the effects of cavity discharge. The results indicated that while aging regions within defects grew rapidly, the overall growth remained slow and stable and is primarily influenced by charge diffusion. Further analysis explored the effects of the internal cavity defects near the electrodes. The presence of defects attracted the aging regions, causing them to grow uniformly without significant morphological changes, highlighting the interplay between thermal and charge-induced aging. The phase-field model effectively captures the dynamics of the aging regions influenced by internal defects, gradient energy, and charge diffusion. This comprehensive understanding enhances our ability to predict material degradation and informs the design of more reliable insulating materials for electrical applications.
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