High Voltage Equipment Research Articles

Up-gradation of the dielectric, physical & chemical properties of cottonseed-based, non-edible green nanofluids as sustainable alternatives for high-voltage equipment's insulation fluids

The use of natural ester oils as electrically insulating fluids has gained significant attention from industries and electrical utilities as they aim to replace traditional mineral oils. However, most natural ester oils are derived from edible products, which has the potential to contribute to the food crisis. Therefore, nonedible green nanofluids made from cottonseed oil (CSO) have been targeted as a keen solution to this issue. However, Al2O3, TiO2, Fe2O3, SiO2, and graphene nanoparticles at (0.025, 0.05, and 0.075 wt/vol%) were used as additives, along with surfactant Olic Ac-id and Ethanol (1:5) due to their promising impact on the dielectric and thermal properties of the nanofluid. The nanofluid synthesis process was practically conducted in HV & Chemical Laboratories using one-step and two-step methods, and their breakdown voltage results and chemical properties (e.g., fire point, flash point, cloud point, pour point, viscosity, acidity, moisture content, resistivity, and dissipation factor) were compared. The physical mechanisms underlying these properties were also analyzed and tested. For the validation of the proposed vegetable oil the results have been compared with traditional mineral oil for high-voltage equipment's. The findings suggest that the proposed nonedible green nanofluids-based cottonseed oil (CSO) has a high potential to be used as electrically insulating fluids, providing a sustainable alternative to conventional mineral oils. Overall, this study provides insights into the use of non-edible green nanofluids as a solution to the potential contribution of natural ester oils to the food crisis. The findings highlight the importance of sustainable solutions in the energy industry and the need for further research in this area.

Development of Second Order High Frequency Filter for Partial Discharge Measurement

Partial discharge (PD) can occur on any high-voltage equipment. This study is particularly concerned with the PD that occurs on underground cables. Researchers frequently struggle to isolate interference noise from the PD signal when doing PD measurements. Therefore, to reduce the interference noise during PD measurements, Sallen-Key high-pass filters with a 500 kHz, or a little bit higher cut-off frequency are designed. This filter is designed with a designated cut-off frequency value because the frequency range of the PD signal is between 1 MHz to 1 GHz. Based on the results of experimental testing for actual filters, the designed filter is a high-pass filter with a cut-off frequency of 500KHz. When the generator function's input frequency values are set between 500 kHz and 2.4 MHz, the signal will pass the filter and provide output values for both frequencies and amplitude. However, at frequencies lower than 500 kHz, the signal is beginning to be filtered and the output signal's amplitude is getting close to zero. Based on the PD testing results, there is interference on the PD signal shown on the oscilloscope when a 1kV supply is applied to an underground cable without using a filter. But, when the proposed filter is used in PD testing, the ripple voltage is reduced from 123 mV to 67 mV. This proves that when the designed filter is used in PD testing, it can reduce interference noise on the PD signal.

A High-Voltage-Specialized Direct-Current Triboelectric Nanogenerator for Air Purification.

Human health and the environment face significant challenges of air pollution, which is predominantly caused by PM2.5 or PM10 particles. Existing control methods often require elevated energy consumption or bulky high-voltage electrical equipment. To overcome these limitations, a self-powered, convenient, and compact direct current high-voltage triboelectric nanogenerator based on triboelectrification and electrostatic breakdown effects is proposed. By optimizing the structure-design of the direct current triboelectric nanogenerator and corresponding output voltage, it can easily achieve an output voltage of over 3kV with a high charge density of 320 µC m-2. A power management circuit is designed to overcome the influence of third domain self-breakdown, optimize 92.5% amplitude of voltage shake, and raise 5% charge utilization ratio. With a device size as tiny as 2.25 cm3, it can continuously drive carbon nanowires to generate negative ions that settle dust within 300 s. This compact, simple, efficient, and safe high-voltage direct current triboelectric nanogenerator represents a promising sustainable solution. It offers efficient dust mitigation, fostering cleaner environments, and enhancing overall health.

High-temperature properties of dry air used as arc quenching medium and its mixture with vaporized C2F4 : reaction products and critical reduced electric field strength at 300–3000 K

Recently, electric power equipment manufacturers released a joint statement with the aim of developing high-voltage electrical equipment completely free of fluorinated gases such as fluoroketones and fluoronitriles, which are considered as alternatives to SF6 and artificially produced compounds of F. This paper considers air as a typical gas present naturally in the environment to investigate its high-temperature properties, including an air mixture with C2F4 vapor injected from a polytetrafluoroethylene nozzle, for application as an arc-quenching medium in a high-voltage circuit breaker equipped with a nozzle. Chemical composition results for the reaction products at 300–3000 K show that the admixture of C2F4 vapor causes a decrease in the molar number of O2 contained in the air, owing to the production of O-containing compounds such as CO2 and CO . Additionally, the results reveal that the admixture of C2F4 vapor lead to the production of CF4 as the predominant F-containing compound. Furthermore, the boundary condition for O2 production in terms of O2 molar number XO2 and C2F4 molar number XC2F4 is formulated. Such evaluation of the mixture composition enables the determination of a reduced effective collision ionization coefficient αˉ/N and a critical reduced electric field strength Ecr/N , resulting in αˉ/N = 0. The strength Ecr/N for the mixture with 30%–100% C2F4 molar fraction rises to approximately 150 Td (1 Td = 1 ×10−21 V m2) over 300–3000 K, which is 20–50 Td higher than that for high-temperature air unmixed with C2F4 vapor. The variation in Ecr/N is discussed in terms of predominant electron impact processes and the electron energy distribution function in the mixture.

Analysis and Preventive Measures for an Abnormity of 220kV Isolating Switch

With the development of the power grid, the cutter brake is a kind of main equipment used cooperatively in the transmission and distribution line of the substations with the circuit breaker in the operation and maintenance of the electric power system. Its main role is to ensure the safety of the staff during the maintenance of high voltage equipment. The cutter brake forms a clear disconnection point to provide the staff with a sufficiently large insulation interval between the equipment in need of repair and other energized parts. In the long-term operation, various reasons may lead to various failures of the cutter brake, causing great security risks to the safe and stable operation of the power grid and personal safety. This paper is mainly focused on analyzing the abnormal phenomenon of the poor contact of the dynamic and static contact fingers of B phase of I cutter brake of Xinlang Line 1 in the 220kV substation, which causes most of the current to flow through the B phase of Xinlang Line 2. Future management and preventive measures for this type of cutter brake are also proposed in this paper.

Assessment of the Arc Resistance of 3D-Printed Insulation Materials for Outdoor High-Voltage Applications

High-voltage electrical equipment insulation often uses composite materials like epoxy resin, cross-linked polyethylene, polyurethane, and silicone rubber as encapsulation. 3D printing technology offers a more efficient and cost-effective solution, producing intricate elements without cutting and casting. Research shows that 3D printed materials have comparable properties to polymer-based insulation, but further testing is needed to evaluate their resistance to harsh environmental conditions. This research investigates the arc resistance properties of 3D printed insulation materials for outdoor high-voltage applications, assessing their suitability for outdoor applications. The wet and dry arc resistance tests were performed in accordance with ASTM D495-99 and IEC-60587. The present work investigated three varieties of samples: polylactic acid, epoxy resin, and silicone rubber. The results of the tests reveal that polylactic acid test samples have average wet and dry arc resistance times of 2.5 hours and 1.4 seconds, which is less than silicone rubber and epoxy resin. Additional research is required to comprehend the behavior of arc formation in polylactic acid insulation materials for high-voltage 3D printing applications.

ВИЗНАЧЕННЯ ТА АНАЛІЗ РОБОЧИХ ХАРАКТЕРИСТИК ВИСОКОВОЛЬТНИХ ЕЛЕКТРОТЕХНІЧНИХ СИСТЕМ НА ОСНОВІ ПОСЛІДОВНОГО ВИСОКОДОБРОТНОГО РЕЗОНАНСНОГО LC-КОНТУРУ

The paper analyzes the performance characteristics of the electrоtechnical system (ETS), built on the basis of a series high-Q resonant LC circuit and intended for diagnosing the isolation of high-voltage equipment. The frequency dependences of the parameters L and C elements of the resonant circuit were experimentally studied and it was shown that for both elements there is an optimal frequency at which the value of the element’s Q- factor reaches its maximum value. It was established that the Q-factor of the investigated circuit is determined mainly by the Q-factor of its inductance and reaches the maximum value QLC,max = 280 at the frequency f= 40 kHz. The Simulink model was developed for the analysis of the performance characteristics of the ETS in steady state. Graphical dependences are given, which allow to determine the level of voltage on the load for a given active resistance of this load, as well as the energy characteristics and the value of the efficiency of the ETS at the stage of its design. A Simulink model has also been developed to analyze the dynamic characteristics of the ETS when a breakdown of the diagnosed insulation occurs. It is shown that the breakdown of the insulation in the ETS, which has a series high-Q resonant circuit, will cause a rapid decrease in current by Q times, and not an increase in current to emergency values, as in an ETS based on high-voltage transformers. In this way, a fast-acting parametric stabilization of the output current is implemented in the ETS even in case of electrical breakdowns of the high-voltage insulation of the power equipment under diagnosis. Thus, the ETS implements high-speed parametric stabilization of the output current, which prevents the destruction of both the ETS and the diagnosed high-voltage insulation of power equipment even during its electrical breakdown. References 11, figures 9.

Significantly Improve the Thermal Conductivity and Dielectric Performance of Epoxy Composite by Introducing Boron Nitride and POSS.

Dielectric materials with superb thermal and electrical properties are highly desired for high-voltage electrical equipment and advanced electronics. Here, we propose a novel strategy to improve the performance of epoxy composites by employing boron nitride nanosheets (BNNSs) and γ-glycidyl ether oxypropyl sesimoxane (G-POSS) as functional fillers. The resultant ternary epoxy composites exhibit high electrical resistivity (1.63 × 1013 Ω·cm) and low dielectric loss (<0.01) due to the ultra-low dielectric constants of cage-structure of G-POSS. In addition, a high thermal conductivity of 0.3969 W·m-1·K-1 is achieved for the epoxy composites, which is 114.66% higher than that of pure epoxy resin. This can be attributed to the high aspect ratio and excellent thermally conductive characteristics of BNNSs, promoting phonon propagation in the composites. Moreover, the epoxy composite simultaneously possesses remarkable dynamic mechanical properties and thermal stability. It is believed that this work provides a universal strategy for designing and fabricating multifunctional composites using a combination of different functional fillers.

Case Article—Digitizing Spare Parts Supply Chain via 3D Printing: An Operational Cost Analysis

The case presents a sourcing problem and a manufacturing problem faced by an original equipment manufacturer, seeking recommendations for sourcing a diverse range of parts for high-voltage equipment, as well as making decisions on the manufacturing strategy for a component used in a water monitoring system. The case provides an opportunity to explore the qualitative and quantitative aspects of three-dimensional (3D) printing versus traditional manufacturing, specifically in terms of operational cost. Furthermore, this case facilitates discussions on the potential impact of 3D printing on supply chains. It is suitable for use in graduate and undergraduate courses, as it introduces key concepts such as manufacturing and inventory policies, queueing theory, and life cycle analysis. Ultimately, the case is designed to promote a deeper understanding of the challenges and opportunities that manufacturers face in today’s rapidly evolving technological landscape. Supplemental Material: The Teaching Note and supplemental data are available at https://www.informs.org/Publications/Subscribe/Access-Restricted-Materials .

Analysis of climatic factors affecting high-voltage overhead lines in the conditions of the Republic of Uzbekistan

The article analyzes the harsh climatic factors affecting the operation of high-voltage power lines in Uzbekistan with hot, dry weather and polluted atmosphere. Based on the analysis of all climatic factors affecting the operation of insulation and other nodes of overhead lines and high-voltage equipment in general, the severity of these factors is shown both in terms of insulation and energy efficiency. Another significant factor has been identified that has a very strong impact on the operation of overhead lines and high-voltage equipment, which was not previously listed in the list of influencing factors in any literature.

Insulation aging and fault diagnosis of high-voltage equipment based on deep Q-networks

In response to the escalating demand for electric energy in the world, the maintenance technology for electric power equipment has evolved significantly. This study addresses the critical issue of insulation aging in high voltage equipment through an innovative approach. By integrating advanced Deep Q-networks (DQN) algorithms and intelligent data mining techniques, our proposed diagnostic scheme enables accurate and timely fault detection. The intelligent DQN algorithms process real-time equipment data, providing essential insights into operational status and faults. Implementing this research offers a strategic framework for enhancing the reliability of high-voltage equipment, contributing to stable system operation, and laying the groundwork for future advancements in equipment condition maintenance.

THE METHOD OF MONITORING THE PARAMETERS OF TRANSFORMER OIL DURING ITS REGENERATION

The dependences of the luminescence flux on the parameters of the GK transformer oil during its regeneration are investigated and a technique for its photoluminescent control is developed. In the process of regeneration, the radiating properties improve – the photoluminescence flux increases. Statistically reliable dependences of the photoluminescence flux on the oil parameters (acid number, breakdown voltage, moisture content and the tangent of the dielectric loss angle) were obtained. For the practical implementation of the photoluminescent control technique of transformer oil, it is advisable to use exciting radiation with a wavelength of 396 nm and flow registration in the range of 412…600 nm. The technique includes sample preparation, excitation and registration of luminescence, signal amplification and determination of the required parameter based on calibration characteristics. The proposed technique can be used to control the quality of oil during its regeneration, as well as during the operation of oil in high-voltage equipment.

Bioinspired Ultra High Frequency Antenna for Partial Discharge Detection in High-Voltage Equipment

Bioinspired Ultra High Frequency Antenna for Partial Discharge Detection in High-Voltage Equipment

Breakdown Characteristics of a Fluoronitrile Mixture Gas According to Mixing Ratio and Oxygen Content for High-Voltage Power Equipment Application

Breakdown Characteristics of a Fluoronitrile Mixture Gas According to Mixing Ratio and Oxygen Content for High-Voltage Power Equipment Application

Study on UAV Inspection Safety Distance of Substation High-Voltage and Current-Carrying Equipment Based on Power-Frequency Magnetic Field

Study on UAV Inspection Safety Distance of Substation High-Voltage and Current-Carrying Equipment Based on Power-Frequency Magnetic Field

Research on visualization monitoring technology of vulnerable high-voltage electrical equipment in substation based on BP artificial neural network

Abstract This study develops a visualization monitoring system for substation equipment operational status, utilizing mobile monitoring technologies. The system architecture integrates a core functional module aligned with comprehensive system requirements, enhanced by a BP neural network to optimize the server’s data mining capabilities. The research focuses on the analysis of typical faults in crucial substation electrical equipment, applying a Fourier algorithm for preprocessing the fault data. Employing the diagnostic principles of the BP neural network, the study designs a thermal fault diagnosis process for the substation apparatus. Experimental scenarios were established to evaluate the BP neural network’s performance by comparing three linear regression sample values. The practical application of the BP neural network model was assessed through integration with substation field data. Cross-validation of the field data indicates that the fault location algorithm accurately identifies 11 types of faults from 85 alarm signals in the secondary condition monitoring of substations, achieving a reliability of 98% or higher, which underscores its high applicability and operational feasibility.

Broadband 3-D Omnidirectional Magnetic Induction-Based Sensor Module for Partial Discharge Detection of High-Voltage Equipment in IIoT Application

Broadband 3-D Omnidirectional Magnetic Induction-Based Sensor Module for Partial Discharge Detection of High-Voltage Equipment in IIoT Application

Partial discharges in power transformers

Tansformers are among the most responsible and expensive elements of the power system, therefore monitoring the technical condition of the transformer is an important and urgent task. One of the signs of aging of insulation in a transformer may be partial discharges (PD), leading to its further failure. The use of monitoring systems based on PD analysis makes it possible to prevent the severe consequences of short circuits in transformers and, as a result, achieve significant economic effects during the operation of controlled high-voltage equipment. The transformer monitoring system based on the partial discharge method is complex and not always effective, because fixed discharges in transformer insulation can be observed for years and do not lead to breakdown, and among the PD it is not always possible to identify the leader's transition to the through phase in time, which creates sufficient conditions for breakdown. In practice, the discharge test is performed using chromatographic analysis of dissolved gases in oil (CADG) or by measuring discharge activity. The article analyzes the effectiveness of PD control methods and the need to develop mathematical models of partial discharges that allow studying the dynamics of the streamer-leader transition in controlled isolation.

การพยากรณ์ยอดขายและความต้องการสินค้าในอุตสาหกรรมผลิตอุปกรณ์ไฟฟ้า กรณีศึกษา บริษัทผลิตอุปกรณ์ไฟฟ้าแรงสูง

The purpose of this study is to find the product demand forecasting model from the artificial neural network method in a case study of a high-voltage equipment manufacturing company. And reduce fines for late delivery of goods by using the Matlab program. The forecasting model is established by using time series neural network method, and the nonlinear autoregressive neural network (NARX) function model is established by combining with external input data. Then the forecast deviation is the average deviation percentage error (MAPE) uses the least dynamics model. By using data that collects product sales from 2019 – 2022 total 48 set of data are divided into 2 data sets used in the study. by the first dataset is learning 36 datasets and the second dataset is learning 12 datasets. The model of this study was defined with the number of hidden layer nodes as 2, 6 and 10. The time delay was 2 and 3. Forecasting models are combined into 6 models. The best model result of each item from NARX forecast through the learning process Levenberg-Marquardt (trainlm), including models 1, 4, 5, 4, 3, 3, and 2 sequential The results show the least average absolute percentage error at 8.32, 5.85, 2.61, 3.39, 2.91, 2.19 and 7.76 and the results of the forecasting model were analyzed to reduce fines from selling all 7 items Able to reduce penalties for late delivery of 4 items showing the percentage of difference in cost reduction equal to 0.28% 0.24% 0.32% and 0.22%. It can be concluded that the prediction of the neural network inverted neural network model It can be used to forecast product sales and product demand as well. And reduce the cost of late delivery fines for better results.

Enhancing grid protection: The crucial role of resistive-type superconducting fault current limiters in transmission line current differential relays

Superconducting fault current limiters (SFCLs) offer an efficient means of limiting fault currents and supporting system reliability. However, they weaken the fault characteristics and reduce the sensitivity of traditional relay protection. The seamless integration of SFCLs with protective relays remains a complex and under-explored area, impeding their widespread industrial adoption. In parallel, current differential protective (CDP) relays are almost the primary protection for all high-voltage electrical equipment and are the cornerstone of global power system security. This paper fills a critical knowledge gap by researching the intricate interaction between resistive superconducting fault current limiters (R-SFCLs) and current differential protective relays. Our investigation commences with a comprehensive mathematical analysis, while researching the influence of R-SFCLs on CDP operation. Subsequently, we conduct a series of comparative experiments using the Matlab Simulink software platform. These tests evaluate the sensitivity, dependability, and security of CDPs in scenarios with and without R-SFCLs. The simulation results not only confirm the accuracy of our analytical framework but also shed light on the multifaceted relationship between R-SFCLs and CDPs. This research contributes to a deeper understanding of how R-SFCLs can be effectively integrated into power systems, offering a roadmap for enhancing grid protection.