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The need for electrical energy in remote areas to improve community welfare must be a concern for universities. The government's ability to build new electricity sources is very minimal because it requires large infrastructure and costs, but the government continues to strive to develop new power plants. Therefore, it is necessary to strive for innovation to build power plants from renewable energy sources. There is a need to use renewable energy as an alternative to replace electrical energy which is increasingly in crisis. One alternative energy that is easy to make is energy that uses magnetic force as a model for generating electricity. Brushless Direct Current (BLDC) motors are an alternative to current DC motors. This three-phase permanent magnet axial flux generator is specially designed for vertical-type wind turbines. This generator consists of two stators and one rotor. where each stator consists of 9 coils and the magnet used is a neodymium permanent magnet. Based on test results, this generator can produce a voltage of 12.57 VDC with a wind speed of 6.84 m/s. So, it can turn on DC lights and charge DC batteries. This three-phase axial BLDC generator was tested in 3 stages, namely without load, using battery load, and DC-light load with wind conditions depending on natural conditions.

The process of converting solar cell electrical energy is a form of utilizing environmentally friendly alternative energy sources (renewable energy). The conversion system is in the form of PV panels that are installed in a location exposed to sunlight and unobstructed. Monitoring is carried out when the sun shines from morning to evening. The location of the panel is in the vehicle parking lot of the engineering faculty, while monitoring is carried out in the Control Laboratory of the Tanjungpura University Engineering Faculty, which is 300 meters away. Factors that determine the quality of PV panels are the system and dimensions. This shows that fluctuations in current (I), voltage (V) and power (P) need to be controlled so that load distribution and reserves can prevent reduced energy generation. Observation and control using Long Range Area (LoRa) radio transmission media connections, Internet of Things (IoT) and Programmable Logical Control (PLC) in real-time. Observation and test results show that energy generation has experienced an increase in temperature which has an impact on reducing power. Meanwhile, the effect of the distance between the installed panels produces an average delay of 7 milliseconds (midday conditions). Meanwhile, the Signal to Noise Ratio (SNR) value for data transmission is 30 dBm at the device frequency of 868.125 MHz. Baud rate 2400-9600 bps with a speed of 0.3 bps – 62.5 Kbps. The application of this system is a research novelty because it can determine and control the generation of electrical energy at minimum, maximum and optimum conditions with a certain distance between the observer and the installed panel.

Distributed generation (DG) is an approach that involves adding decentralized power generation within a distribution network. Distributed generation systems can reduce transmission losses, increase the reliability of energy supply, minimize carbon emissions, and enable the active participation of consumers in energy production. However, with the increase in distributed generation, electric power systems face new challenges in maintaining operational reliability and safety. Disruptions such as short circuits or overcurrent can occur in the system, and appropriate protective responses are required to protect the power grid from more significant damage. The addition of DG also causes the short circuit current to vary and results in system protection coordination having to be redone. Carrying out coordination will take a long time. This research uses modeling and simulation of a distributed generation system with various operating conditions and works adaptively according to changes in the system due to the addition of DG. The results obtained from the simulation are used in neural network training to study the relationship patterns between directional overcurrent relays (DOCR) parameters and system operating conditions. The backpropagation algorithm is used in the Artificial Neural Network (ANN) training process. The training process utilizes the maximum Short Circuit Current (ISC) input obtained through generation, fault location, and fault type. Time Dial Setting (TDS) and Ipickup values are used as ANN training targets. After testing, the results obtained are in accordance with the target data. The efficacy of this method is further demonstrated through ETAP simulations, which confirm that ANN is a suitable approach for modeling adaptive and optimal relay coordination systems.

This study aims to obtain the type of grounding and resistance value in the distribution system of medium voltage UP3 South Surabaya ducts. In addition, to see the magnitude of the comparative value of the results of the resistance analysis stimulates ETAP. In the South Surabaya UP3 medium voltage distribution system. PT. PLN (Persero) improves and optimizes service to all of its customers. The grounding system at PT PLN UP3 South Surabaya. The existing PLN UP3 South Surabaya must comply with PUIL regulations of 2011, and the value of land holdings must be no greater than 5 Ω. Of the 15 grounding points analyzed, there are 3 points whose grounding values do not meet the requirements of PUIL 2011, namely the grounding values are still above 5 Ω. The smallest grounding resistance value before adding the rod electrode is 1.1 Ω at the 3rd point or BD 313 and after adding one rod and then paralleling it, the resistance value drops to 0.55 Ω. For the largest grounding resistance at the point that meets the requirements, namely 4 Ω at the 9th point or BD 653 and after adding one rod and then parallelizing it, the resistance value drops to 1.75 Ω. ETAPsimulation, the simulation results are affected by the value of x direction and the depth of the conductor. In addition, the simulation results are affected by the size of the rod. ETAP simulation results, the touch tolerable is 587.6 volts and the step tolerable is 1948.6 volts. For the largest grounding resistance at the point that meets the requirements, namely 4 Ω at the 9th point or BD 653 and after adding one rod and then parallelizing it, the resistance value drops to 1.75 Ω. ETAP simulation, the simulation results are affected by the value of x direction and the depth of the conductor. In addition, the simulation results are affected by the size of the rod. ETAP simulation results, the touch tolerable is 587.6 volts and the step tolerable is 1948.6 volts. For the largest grounding resistance at the point that meets the requirements, namely 4 Ω at the 9th point or BD 653 and after adding one rod and then parallelizing it, the resistance value drops to 1.75 Ω. ETAP simulation, the simulation results are affected by the value of x direction and the depth of the conductor. In addition, the simulation results are affected by the size of the rod. ETAP simulation results, the touch tolerable is 587.6 volts and the step tolerable is 1948.6 volts.

This study evaluates the performance of a 36 Volt 10 Ah battery in an electric bicycle with a 350-Watt Brushless DC (BLDC) motor as an environmentally friendly alternative to overcome the negative impacts of motorized vehicle use in Indonesia. In addition, this study measured the State of Health battery’s value of internal resistance, which is different from other studies that use capacity fading. With a focus on maximum travel distance and travel time, experiments were conducted without load and with a 70kg load. The no-load test was conducted only once, resulting in a travel time of 600 minutes and a distance of 330.1 Km. Although the battery was not discharged, the results were not in line with expectations, so the no-load test was only conducted once. In the 70kg load test, six trials were conducted with variable measurements of distance, battery voltage, and battery resistance. Results showed variations in distance between 50.7 km and 53.1 km, and travel time between 151 and 160 minutes. The battery voltage varied from 31.316 Volts to 31.850 Volts. The resistance in the battery also showed an increase of about 0.0001 ohms from 0.1132 ohms to 0.1139 ohms. Overall, the results from the study showed that as time and usage progressed, the battery voltage and internal resistance values tended to increase, while the distance and travel time tended to decrease. The internal resistance measurement method proved to be effective in assessing battery health as the State of Health value decreased throughout the experiment.

An electric motor is an electromagnetic machine commonly utilized across various industries and automotive products. One prevalent type of electric motor employed in electric vehicles is the Permanent Magnet Brushless DC Motor (PM-BLDC), a brushless motor employing permanent magnets. However, despite its efficiency, permanent magnet motors often experience vibrations that can disrupt their performance. This research aims to optimize the existing BLDC motor design, with a specific focus on reducing the existing cogging torque. Initially, the existing design exhibited a cogging torque level of 0.21482 Nm. The optimization process involved modifications to several key design parameters, such as air gap, magnet thickness, magnet type, and slot opening width. In previous research, only comparisons were made between stator slot designs, which proved to be less effective as significant differences were not evident in the results of the comparative analysis of BLDC motor designs. So, in this research, the Taguchi method was utilized for the optimization process due to several advantages it offers. Through an analysis of means and variance, the optimization process successfully achieved a significant reduction in cogging torque by 0.099744 and an increase in efficiency by 0.6%. The results of the optimized permanent magnet BLDC design indicated a cogging torque value of 0.115072 Nm and an efficiency of 86.64% at an operational motor speed of 1500 rpm. This research provides a substantial contribution to the development of more efficient electric motors suitable for various applications.

This study focuses on conceptualization and development of a battery management system (BMS) with two main functions, battery monitoring and management, in the context of brushless direct current motors (BLDCs). The main challenge in variable estimation is to protect the battery from potential risks during the charge and discharge cycle. The new proposed resolution combines a comprehensive BMS with monitoring capabilities for charge (SoC), health (SoH), voltage, current and battery temperature. In addition, a protective mechanism is incorporated to prevent variables from overshooting safety parameters. This research uses two different methodologies for estimating SOC, coulomb counting and open circuit voltage. In experimental tests, resistance potentiometers of 1,650, 3,300 and 0 were used, with SoC estimates of 37%, 19% and 65%, while coulomb counting method has a marginal error of 1.13%. On the contrary, the open-circuit voltage method generated a SoC estimate of 0% for all potentiometer resistance, with an error rate of 0.64 %. As a result, the open circuit voltage method is chosen because of its superior accuracy compared to the coulomb counting method. The state assessment of the battery showed a value of 100% after seven cycles. In addition, a protective system has been implemented to ensure that battery variables remain within the safe thresholds throughout the charge and discharge process. Consequently, the implementation of this BMS is expected to significantly improve overall performance and extend battery life.

Salted egg is one of the egg types that has a lot of devotees because it tastes a little salty and savory. Salted eggs are usually homemade in various regions. The easy process of making them has attracted many people to do so. This study developed a PLC-based on automatic system for a salted egg maker using the osmotic pressure method to accelerate the opening of the semi-permeable membrane on duck eggshells so that the salting mixture seeps into the eggs more quickly. It was carried out in an osmotic pool containing water and acetic acid at a concentration of 5%. The data collection process in designing the salted egg maker consisted of evaluating the performance of photoelectric sensors, proximity sensors, temperature controller, thermostat set point, baking time, and salted egg durability test. The results of the tests indicated that the time needed to make salted eggs from raw eggs to cooked eggs only took 36 minutes using the machine designed. Additionally, the presented salted egg maker reveals the short making time, and long salted egg durability. altogether revealing full potential to be easily used for practical applications.

The grounding system is one of the security systems in substations to channel excess voltage caused by lightning strikes that occur at substations, as well as electrical equipment. To design a grounding system, there are several factors that must be considered, including the type of soil, the configuration of the grounding system, the resistivity of the soil, and the condition of the surrounding environment. The aim of this research is to determine the safe limits in the substation grid grounding system which is influenced by the type of soil and influences the touch voltage and step voltage, which can be dangerous to humans. The method used is simulation with the Finite Element Method (FEM) in the ETAP application. Finite Element Method (FEM) is a method that uses image mediation by assuming that the grounding system is an equipotential structure. The test results were deliberately carried out with larger substation area parameters and different soil types, so that the differences between the influence and appearance of touch voltage and step voltage can be seen clearly.

To control non-communicable diseases, the NCD Posyandu (integrated service post) monitors and detects possible risk factors for non-communicable diseases in the community. This study used qualitative research methods with in-depth interview questionnaires for informants at the NCD Posyandu, UPT Puruk Cahu Health Center. The study’s results comparing the NCD Posyandu implementation standards for 2014 showed that the NCD Posyandu work area had good and competent cadres, with patients getting NCD services and counseling for free. Recommendations are needed to improve partnerships, funding support, and NCD Posyandu implementation tools, increase the number of cadres, and provide training to all NCD Posyandu cadres and meetings for the community on non-communicable diseases so that coordination among all parties in NCD Posyandu, including the community, runs optimally both in quality and quantity.

Kampar Polytechnic has a miniplan laboratory for processing CPO into cooking oil, biodiesel, and soap. During its operation, this processing produces liquid waste and solid waste. The waste released must be treated before being discharged into the environment, provided that the amount of COD reduction efficiency is good enough (63,41%). The COD content in wastewater is still above environmental quality standards. To reduce COD according to permissible standards, recycling is carried out with effluent from the sedimentation process returned to the equalization unit. The design of equalization, coagulation, and flocculation tubs has been successfully carried out. The results obtained are the dimensions of the equalization bath at 2m length, 2m width, and 1.2m height. The dimensions of the coagulation bath are 1.5m long, 1.0m wide, and 1.2m high. The dimensions of the flocculation bath are 2.5m long, 1.5m wide, and 1.2m high, with the provision that consideration meets the volume of liquid waste treated.

North Sumatra is one of the provinces that contributes the most prominent agricultural commodities of red chilies and cayenne peppers in Indonesia. This study aims to determine the outcomes of price forecasts for cayenne and red chilies in the province of North Sumatra. The method used is multivariate singular spectrum analysis. Results were grouped into six groups based on 12 eigenvectors with a forecast length of 9 monthly periods. Further, the level of accuracy was obtained from MAPE for each variable, with the highest MAPE being 30% for the curly red chili, 27.55% for the big red chili, and the lowest at 23.44% for mixed cayenne pepper. So, the price forecast for red chilies and cayenne peppers in North Sumatra Province for October 2023 to June 2024 using the Multivariate Singular Spectrum Analysis model is included in the forecast category with reasonable capabilities.

Pumpkin (Cucurbita moschata Duch) is a food rich in vitamin A, vitamin C, minerals, carbohydrates, and flavonoid compounds. Flavonoids have several pharmacological activities, including as antioxidants to ward off free radicals. This study aims to determine the total flavonoid content and antioxidant activity of pumpkin fruit. The extraction of pumpkin fruit was done by the maceration method in a 70% ethanol solvent. The total flavonoid test used the colorimetric method with a 10% AlCl3 reagent and quercetin as a positive control. Antioxidant activity was tested using the DPPH (1,1-diphenyl-2-picrylhydrazyl) method. The results obtained for the total flavonoid content of the ethanol extract of pumpkin fruit amounted to 1.741 mgQE/g ± 0.2438 and an IC50 value of 379.44 ppm, including the category of weak antioxidant, compared with the positive control.

Antioxidant compounds play an essential role in health because they can reduce the risk of chronic diseases such as cancer and coronary heart disease. This study analyzed the antioxidant activity of red fruit oil and juice. This study used an experimental method with oil and juice obtained through boiling for 4-5 hours. The stages of the study include flavonoid qualitative tests and antioxidant activity tests using the DPPH method using UV-Vis Spectrophotometers. Based on the research results, oil and red fruit juice contain flavonoids that have the potential to be antioxidants. Antioxidant activity test with the DPPH method showed IC50 in red fruit oil products on the market at 30.11 ppm and red fruit juice at 31.80 ppm, showing vigorous antioxidant activity compared to homemade red fruit oil with an IC50 of 85.98 ppm.

Introduction. High-speed linear pulse electromechanical converters (LPEC) provide acceleration of the executive element in a short active section to high speed with significant displacement, while power-purpose LPECs create powerful power impulses of the executive element on the object of influence with minor movements. One of the areas of improvement of LPEC is the creation of multi-armature structures. Methodology. To analyze the electromechanical characteristics and indicators of LPEC, a mathematical model was used, which takes into account the interconnected electrical, magnetic, mechanical and thermal processes that occur when connected to a pulse energy source with a capacitive energy storage. The main results of the calculations were performed in the COMSOL Multiphysics software environment and confirmed by experimental studies in laboratory conditions. Results. The features of the electromechanical processes of multi-armature LPECs are established and their indicators are determined. With the help of efficiency criteria, which take into account electrical, power, speed and magnetic indicators in a relative form with different options for their evaluation strategy, it was established that multi-armature LPECs for power purposes have increased efficiency, and for high-speed LPECs the use of multi-armature configurations is impractical. The conducted experimental studies confirm the reliability of the calculated results. Originality. It has been established that almost all multi-armature LPECs for power purposes have higher efficiency compared to a converter with one armature, and for high-speed LPECs it is advisable to use traditional LPECs with one armature. Practical value. On the basis of multi-armature LPECs, models of an electromagnetic UAV catapult, a magnetic pulse press for ceramic powder materials, an electromechanical device for dumping ice and snow deposits from a power line wire, a device for destroying information on a solid-state digital SSD drive have been developed and tested. References 20, tables 4, figures 8.

Introduction. A special category among induction machines with a massive rotor is occupied by the class of multifunctional electromechanical energy converters, which are integrated with the links of technological processes Problem. The exchange of reactive energy between the source and the electromechanical converter during periods of operation with a low load leads to a significant decrease in its efficiency and power factor. With the use of non-linear loads and taking into account possible resonance, it has become more difficult to improve the power factor by installing capacitor banks. Goal. Increasing the energy indicators of the electromechanical converter by spatial displacement of the main and additional stator windings and internal capacitive compensation. Methodology. Comparative analysis of connection schemes and spatial arrangement of stator windings when using internal capacitive compensation. Modeling and experimental studies of electromagnetic and electromechanical characteristics of a screw electromechanical converter. Results. The distribution of electromagnetic quantities was established and the choice of the angle of spatial displacement of the main and additional windings of the stator phases of the modified converter, which ensure an increase in the value of the electromagnetic torque and power factor, was justified. The results of experimental studies of the screw electromechanical converter are presented. Originality. For the first time, a method of internal capacitive compensation of reactive power is proposed for multifunctional electromechanical converters of technological purpose. Practical value. The use of the proposed method of spatial displacement of the main and additional stator windings and internal capacitive compensation will ensure an increase in the energy performance of the screw electromechanical converter. References 23, tables 3, figures 15.

Aim. Development of the method of designing a combined electromagnetic shield, consisting of active and passive parts, to improve the effectiveness of reduction of industrial frequency magnetic field created by two-circuit overhead power lines in residential buildings. Methodology. The problem of design of combined electromagnetic shield including robust system of active shielding and electromagnetic passive shield of initial magnetic field solved based on of the multi-criteria two-player antagonistic game. The game payoff vector calculated based on the finite element calculations system COMSOL Muliphysics. The game solution calculated based on the particles multiswarm optimization algorithms. During the design of combined electromagnetic shields spatial location coordinates of shielding winding, the currents and phases in the shielding winding of active shielding, geometric dimensions and thickness of the electromagnetic passive shield are calculated. Results. The results of theoretical and experimental studies of combined electromagnetic passive and active shielding of magnetic field in residential building from power transmission line with a «Barrel» type arrangement of wires presented. Originality. For the first time the method of designing a combined electromagnetic shield, consisting of active and passive parts, for more effective reduction of the magnetic field of industrial frequency created by two-circuit overhead power lines in residential buildings is developed. Practical value. Based on results of calculated and experimental study the shielding efficiency of the initial magnetic field determined that shielding factors whith only electromagnetic passive shield is more 2 units, whith only active shield is more 4 units and with combined electromagnetic passive and active shield is more 10 units. It is shown the possibility to reduce the level of magnetic field induction in residential building from power transmission line with a «Barrel» type arrangement of wires by means of a combined electromagnetic passive and active shielding with single compensating winding to 0.5 μT level safe for the population. References 53, figures 15.

Introduction. This work presents a methodology for detecting inter-turn short circuit (ITSC) and broken rotor bars (BRB) fault in variable speed induction machine controlled by field oriented control. If any of these faults are not detected at an early stage, it may cause an unexpected shutdown of the industrial processes and significant financial losses. Purpose. For these reasons, it is important to develop a new diagnostic system to detect in a precautionary way the ITSC and BRB at various load condition. We propose the application of discrete wavelet transform to overcome the limitation of traditional technique for no-stationary signals. The novelty of the work consists in developing a diagnosis system that combines the advantages of both the discrete wavelet transform (DWT) and artificial neural network (ANN) to identify and diagnose defects, related to both ITSC and BRB faults. Methods. The suggested method involves analyzing the electromagnetic torque signal using DWT to calculate the stored energy at each level of decomposition. Then, this energy is applied to train neural network classifier. The accuracy of ANN based on DWT, was improved by testing different orthogonal wavelet functions on simulated signal. The selection process identified 5 pertinent wavelet energies, concluding that, Daubechies44 (db44) is the best suitable mother wavelet function for effectively detecting and classifying failures in machines. Results. We applied numerical simulations by MATLAB/Simulink software to demonstrate the validity of the suggested techniques in a closed loop induction motor drive. The obtained results prove that this method can identify and classify these types of faults under various loads of the machine. References 31, table 1, figures 9.

Introduction. Most electromagnetic compatibility studies carried out in the context of power switch research are generally valid for low frequencies. This frequency restriction appears to be too restrictive for a complete analysis of the electromagnetic interference conducted. The novelty of this work lies in the load-dependent an optimal selection of IGBTs and MOSFETs for least-disturbance power switching in the frequency range from 150 kHz to 30 MHz, based on an optimal experimental selection procedure and show the impact of load value on switch switching and noise generation. Purpose. Analysis of the fundamental possibility of selecting a switching device with a power supply based on an experimental measurement which allows to increase the reliability of the entire mechanism operation and significantly simplify the design. Methods. In this paper, the proposed study is used and compared with experimental results at low and high frequencies. Then, a comparison is made for conducted electromagnetic interference (common-mode and differential-mode) generated by IGBT and MOSFET for different loads, and the proposed methodology is verified on an experiment suitable for predicting terminal overvoltage analysis and conducted electromagnetic interference problems. Practical value. The primary method for establishing a conducted electromagnetic interference source for switching devices is based on IGBT and a MOSFET depending on the resistive load. References 22, figures 17.

Aim. Study of the distribution of a three-dimensional alternating quasi-stationary electromagnetic field at the surface of conducting half-space with strong skin-effect, the source of which is an arbitrarily oriented magnetic moment. Methodology. The expressions for non-uniform electromagnetic field with strong skin effect are used for the analysis, which is based on the found exact analytical solution of the general three-dimensional problem and the use of expansion into asymptotic series with respect to a small parameter that is proportional to the ratio of the field penetration depth to the distance between the sources of the external field and the surface of body. Specific expressions at the surface are completely determined by the known field of external sources. In this work, the external magnetic moment field is used. Results. For strong skin effect, expressions for the electric and magnetic field strength are obtained separately for the components of the magnetic moment oriented perpendicularly and parallel to the flat surface between the dielectric and conducting areas. The features of the electromagnetic field distribution are analyzed depending on the value of introduced small parameter. The results are presented for the module and phase shift of the field strength with respect to the phase of the external field source. Originality. The expressions found for the electromagnetic field appear to be more general than the use of closed contours with alternating current, since they extend types of external field sources and allow the use of the superposition method instead of integration over the entire contour. Practical value. The found specific analytical expressions of the electromagnetic field at the surface for the external field of magnetic moments significantly simplify the solution of the problems, since they do not require additional solution of the field equations. References 20, figures 8.

Goal. Decision of problem scientific and technical task on the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory basic component of complete pulse current of artificial lightning with the rationed amplitude-temporal parameters (ATPs) with the use of the modernized generator of current of lightning of type of UITOM-1. Methodology. Bases of the applied electrical engineering, electrodynamics and electrophysics, electrophysics bases of technique of high-voltage and high pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Information, which specify on a decision at Research and Design Institute «Molniya» of National Technical University «Kharkiv Polytechnic Institute» problem scientific and technical task, related to the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory of complete pulse current of artificial lightning, which contains pulse A- (repeated pulse D-), intermediate B- and long-term C- (shortened long C*-) components of this current, is resulted, ATPs which answer the hard technical requirements of normative documents of the USA of SAE ARP 5412: 2013, SAE ARP 5414: 2013 and SAE ARP 5416: 2013. Short information is indicated about the applied electrical circuits of separate high-voltage generators of pulse currents of condenser type of GIC-A (GIC-D), GIC-B and GIC-C (GIC-C*), which it is worked as synchronous appearance on the general electrical loading in composition the modernized powerful high voltage generator of complete pulse e current of artificial lightning of type of UITOM-1, and in-use high-voltage measuring facilities which contain the heavy-current low-resistance shunts of type of SHK-300 for simultaneous registration with their help on examinee on stability to lightning devices objects of aviation and space-rocket technique of ATPs proper component of complete i pulse current of artificial lightning. Technical examples are resulted and the row of results of practical application of the indicated domestic powerful high-voltage proof-of-concept electrophysics equipment is described at the tests of elements of some aircrafts (ACs) on resistibility to the direct action on them of complete pulse current of artificial lightning with rationed ATPs. Originality. A problem is formulated and having the important applied value in area of aviation and space-rocket technique for the leading countries of the world scientific and technical task on the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory indicated component of complete pulse current of artificial lightning with rationed ATPs and concrete electro-technological ways and hardware are indicated for its successful decision. Practical value. The use of the modernized powerful high-voltage generator of complete pulse current of artificial lightning of type of UITOM-1 developed in practice and created in Ukraine will allow to conduct the real verification on resistibility to the action of lightning of different side systems, devices and construction elements, containing metallic and composition materials, both again developed and modernized ACs, that will be instrumental in the increase of vitality of such ACs in the extreme terms of their flight and stay in an electrical active earthly atmosphere with flowing in it storm electrical discharges. References 30, tables 3, figures 20.

Introduction. Pulse regulators are widely used to match the output resistance of the source with the load resistance in order to ensure the possibility of taking maximum power when the value of the load resistance changes. Problem. In the case of using non-traditional and renewable sources of electrical energy, for a more uniform supply of energy to the load, a battery is often connected to the output of the pulse regulator, which works in buffer mode. In such cases, the load for the pulse regulator will be the battery itself, and the role of the source load will be performed by the input resistance of the regulator. To ensure the mode of operation of the pulse regulator, in which the maximum power will be transmitted from the source to the load, it is necessary to know the regulating characteristics of the regulator. There are works that analyze the regulating characteristics of step-up and step-down pulse regulators, which are used to match the load with the output resistance of the source. At the same time, for the same purpose, pulse regulators of the step-up and step-down type can be used. Goal. The purpose of the work is to analyze the features of the operation of step-up and step-down type pulse regulators in the mode of maximum power transmission from the source to the battery, as well as to determine the conditions under which it is possible and appropriate to use such regulators for the specified purpose. Methodology. The regulating characteristics of step-up and step-down type pulse regulators with sequential and parallel switching on of the controlled key were determined and analyzed, taking into account the presence of a battery at their output. Results. It is shown that the transfer of energy from the source to the battery is possible only under certain modes of operation of the regulator, which depend on the type of regulator, as well as the amount of voltage on the battery. The conditions under which it is possible to draw the maximum power from the source are determined. Originality. Since the output resistance of the source and the load resistance are of the same order in the maximum power selection mode, the internal resistance of the power source was taken into account when determining the regulating characteristics of the regulators. Practical value. The obtained results made it possible to formulate practical recommendations for a justified choice of the regulator’s operating modes, depending on its type and the value of voltage on the battery. References 15, tables 1, figures 4.

This research explores the thermal ageing influence on the Low Density Polyethylene (LDPE) dielectric properties, which is utilised as electrical insulation in high-voltage cables. An accelerated thermal ageing test was done at four temperature ranges ranging from 25 °C to 120 °C to define the degree of material deterioration under thermal ageing and to prevent its failure. LDPE composite samples were made by adding aluminium oxide (Al2O3) inorganic filler in two different grain sizes (nano and micro) with various concentrations. The effect of adding inorganic filler on the acceleration of the thermal ageing of the polymer was studied by heating the samples for different periods of time and measuring the dielectric strength of the samples. The obtained results show that thermal ageing considerably affects the electrical properties of the material. The LDPE/Al2O3 nanofiller sample has the highest dielectric strength value at different temperatures. Thermogravimetric analysis was used to investigate the thermal characteristics of materials. The mechanical characteristics of LDPE polymer are studied using tensile strength and elongation at break tests. References 27, table 4, figures 6.

Introduction. This paper focuses on a renewable energy system coupled to a dual purpose power grid via a parallel active power filter for injecting photovoltaic energy into the grid and improving the power quality in the presence of the non-linear load. The novelty of the work consists in the combination of two advanced techniques – Fuzzy Logic Controller (FLC) and the optimized Anti-Windup Fractional Order Proportional-Integral Differentiator (AW-FOPID) regulator based on Particle Swarm Optimization with the Spreading Factor (PSO-SF) algorithm, applied to the improved Direct Power Control (DPC) strategy under different conditions related to climate changes and healthy or infected electrical network. Purpose. Its main role is to improve the power quality and reject the perturbations deforming the electrical network under distorted, unbalanced and balanced grid voltage conditions. Besides, the FLC is employed the Maximum Power Point Tracking (MPPT) under any weather conditions. In addition, the optimized AW-FOPID controller leads to keep the DC bus voltage at its reference value with small undershoots and overshoots in the voltage with a short response time in steady or dynamic states. Methods. The rejection of disturbances affecting the grid is offered by the improved DPC. On the other hand, an intelligent method based on fuzzy logic was used MPPT under any weather conditions. Furthermore, an AW-FOPID regulator based on PSO-SF algorithm is used to keep the DC bus voltage at its reference value with small undershoots and overshoots in the voltage, while keeping a fast response time. Results. The proposed system control is evaluated in various states of power source: distorted, unbalanced, and balanced by simulation using MATLAB/Simulink. The simulation results illustrate the effectiveness and performance of the studied control strategies. References 26, tables 8, figures 16.

Abstract A simulation analysis and an experiment are carried out to investigate how the gap difference between the breaks of a direct current vacuum circuit breakers with multi‐breaks (MB‐DC VCB) caused by the mechanism dispersion of the breaker influences the distribution of TRV among the breaks. An interruption model of MB‐DC VCB, combining the continuous transition model, is established to analyse the rising rate of transient recovery voltage and the dielectric strength recovery speed of the breaks for MB‐DC VCB under different gap difference conditions. Based on the experimental platform of dual break DC vacuum circuit breaker breaking, the correctness of the simulation model is verified on a DC VCB with the double‐breaks interruption experimental platform. Moreover, a model is applied to the non‐synchronous interruption simulation of a DC VCB with three‐breaks. The relationship between the TRVs of the breaks under different gap difference conditions is analysed using the comparative analysis method, obtaining the maximum gap difference at the moment of breaking failure. The results of this study show that large‐gap breaks have a higher TRV than small‐gap breaks (the fracture of the action delay module), with double fractures reaching 1.4 times and triple fractures reaching a maximum of 1.52 times; the ability of small‐gap breaks to withstand TRV is weak, giving rise to re‐breakdown or even interruption failure; as the number of fractures increases, the maximum gap difference also increases. Improving the synchronous interruption ability of the MB‐DC VCB is conducive to improving the interruption performance and interruption success rate of this type of a circuit breaker.

Abstract The strain clamps and leading wires are important components that connect conductors on overhead transmission lines and conduct current. During operation, poor contact between these components can cause abnormal overheating, leading to electric failures and threatening power system reliability. Recently, the use of unmanned aerial vehicles equipped with infrared thermal imagers for strain clamp and leading wire maintenance has become increasingly popular. Deep learning‐based image recognition shows promising prospects for intelligent fault diagnosis of overheating faults. A pre‐treatment method is proposed based on dynamic histogram equalisation to enhance the contrast of infrared images. The DeepLab v3+ network, loss function, and existing networks with different backbones are compared. The DeepLab v3+ network with ResNet101 and convolutional block attention module added, and the Focal Loss function achieved the highest performance with an average pixel accuracy of 0.614, an average intersection over union (AIoU) of 0.567, an F1 score of 0.644, and a frequency weighted intersection over union of 0.594 on the test set. The optimised Atrous rates has increased the AIoU by 12.91%. Moreover, an intelligent diagnosis scheme for evaluating the defect state of the strain clamps and leading wires is proposed and which achieves a diagnostic accuracy of 91.0%.

Abstract Accurate simulation of lightning‐induced overvoltage for overhead distribution lines is helpful to prevent lightning trip accidents. An electromagnetic return‐stroke model was used to represent lightning and then a 3D finite‐difference time‐domain (FDTD) method was adopted to simulate the lightning‐induced overvoltage on a distribution line without a field‐line coupling model. How lightning‐induced overvoltage behave for different ground conductivity and varying distance between the distribution line and the lightning channel was analysed. The results showed that the overvoltage waveforms at the centre point of the line corresponding to lightning strikes on the lossy ground and an ideal ground (σ = ∞) were similar; however, the peak amplitudes of the waveform were affected by soil conductivity at a close distance. The relationship between magnitude of the overvoltage and distance can be described by a second‐order exponential decay equation. Finally, the overvoltage calculated using the proposed model was compared with those obtained based on Agrawal's model and measurements made using the newly developed intelligent insulator on site. From these comparisons, it could be concluded that the FDTD method with the electromagnetic return‐stroke model produces reasonably accurate results of the attenuated oscillation waveform, which can better reproduce the overvoltage on operational distribution lines.

Abstract Oil‐paper insulation material is an essential component for oil‐filled transformers, and polyimide (PI) insulation paper is a novel material in the field of electricity. The improvement of insulation class for insulation paper has gained significant attention in recent years. In this study, SiO2 nanoparticles were modified with a silane coupling agent (KH550), and the KH550‐SiO2 was added to the fibre membrane through in situ polymerisation. The chemical composition and microcosmic characteristics of the PI porous fibre membrane were characterised using FT‐IR and SEM FT‐IR and SEM. Consequently, the dielectric constant of the composite paper was reduced to 2.3 upon adding 3 wt% of KH550‐SiO2, and the dielectric strength reached its maximum value of 85 kV/mm. The results demonstrate that the insulation performance of the KH550‐SiO2/PI composite was significantly improved due to the incorporation of nano‐SiO2. This establishes an efficient approach for achieving excellent electrical and thermal properties in practical applications using the KH550‐SiO2/PI fibre membrane.

Abstract The micro‐defects in epoxy‐based insulation materials generate a local high electric field which results in continuous degradation, seriously endangering the insulation system of gas‐insulated switchgears. A highly sensitive detection technique is reported for micro‐defects of insulation pull rods based on the photon counting (PC) technique. The results demonstrated that for an epoxy‐based insulation pull rod, the photons released during electroluminescence and ionisation at 2 kV, which is less than the partial discharge inception voltage, can be clearly detected. The findings presented a strong correlation between photon counts and defect severity. Discourse has been conducted to elucidate the mechanism behind defect‐induced PC, employing the amplification of ionising luminescence through electric field distortion induced by micro defects and the augmentation of electroluminescence through the aggregation of trap charge. In this regard, the authors verified that PC can serve as a potential tool in the detection of micro‐insulation defects, which also has huge potential in online insulation condition monitoring.

Abstract A high‐temperature superconducting (HTS) dynamo flux pump can inject DC currents into closed‐loop HTS magnets without contact. It enables the realisation of current‐lead‐free or even through‐wall charging systems for high‐field applications such as nuclear magnetic resonance/magnetic resonance imaging (MRI) magnets, fusion reactors and accelerators. Researchers have proposed many simulation models to understand the working principle of HTS dynamos, few of which are in 3D because of converging problems. Therefore, the influences of many key 3D parameters in the HTS dynamo are scarcely reported. The authors propose an efficient 3D modelling method of the HTS dynamo based on the T‐A formulation. The rotating magnets are modelled by a ring‐shaped permanent magnet with space‐time‐variant remanent flux density to avoid moving meshes. This, together with the T‐A formulation, makes the 3D model efficient and universal. The accuracy of the model is verified by the experimental instantaneous and time‐integrated dynamic voltages. Using this model, the authors present systematic case studies to thoroughly explore the influences of the key parameters of a dynamo flux pump on the dynamic voltage and losses. The proposed modelling method and results could significantly benefit the design and optimisation of HTS dynamos for high‐field magnets.

Abstract A wireless signal transmission technology based on acoustic carrier is proposed, which overcomes the limitation of electromagnetic signal shielding and shows great potential for in‐site monitoring of sliding electrical contact used in gas‐insulated switchgear (GIS)/gas‐insulated transmission line (GIL). Here, the state parameter of the sliding electrical contact is modulated onto the frequency domain of an ultrasound wave. As a mechanical wave, the ultrasonic wave is immune to electromagnetic shielding, so that it could carry the sensing signal to penetrate the metal shielding layer and transmit to the external terminals of GIS/GIL. The principle and signal modulation process of the acoustic carrier based transmission system have been demonstrated in detail. Both simulation and experiment have been conducted to analyse the system characteristics as well as optimise the system configuration. As a proof‐of‐concept application, the in situ and on‐line monitoring of the thermal rise of a slide electrical contact both in a current loading equivalent model and a prototype of GIS is demonstrated. Experimental results fit well with the physical process, and show a good measurement accuracy of 0.6% and temperature sensitivity of 400 Hz/°C.

Abstract A key factor limiting the development of silicone rubber insulating materials is their short service life in harsh operating environments. The establishment of a self‐healing system is desired to improve the long‐term operational performance of silicone rubber and effectively extend its service life. In this study, poly(urea‐formaldehyde) microcapsules containing polydimethylsiloxane healing agents are prepared and a dual‐component microcapsule self‐healing system for silicone rubber material is established and optimised. In addition, the key factors affecting the self‐healing performance (such as microcapsule size, rupture rate, and microcapsule doping amount) are investigated. It is found that when SYLGARDTM 184 is used as the healing agent and matrix, with a 4:6 (A:B) doping ratio of dual‐component microcapsules and 20 phr doping amount, the self‐healing efficiency is approximately 51%. Furthermore, increasing the microcapsule rupture rate and the interface strength between the healing agent and the matrix can effectively improve the self‐healing performance. The relationships between key factors and self‐healing performance are theoretically revealed. Based on the relationships, the microcapsule self‐healing system can be appropriately designed. The results of this paper can provide a reference for the development of long‐life silicone rubber insulating materials.

Abstract The potential of using eco‐friendly thermoplastic polypropylene (PP)‐based insulation for high voltage direct current (HVDC) cable has been widely investigated but much less work on the PP‐based semiconducting screen (SC). Considering a long service life (>30 years) under high temperature and high electrical stress is required for typical HVDC cables, and investigations on the effect of antioxidant (AO) concentration and thermal oxidative stability, mechanical, and electrical properties of PP‐based SCs have been conducted. It has been demonstrated that an appropriate combination and amounts of AOs are critical for achieving high thermal stability and maintaining the mechanical properties of SC after ageing in a harsh environment (150°C, with Cu, in air, 7 days). Although higher amounts of space charges have been observed in SC/PP/SC samples with higher AO concentrations, the impact on space charge behaviours is less after ageing, suggesting that ageing (or operating at high temperature) leads to microstructure evolution in SC and can potentially mitigate space accumulation in PP‐based insulating materials.

Abstract Computational screening of single gases to replace SF6 for electrical insulation has been challenged by the difficulty in combining various mutually exclusive properties especially for dielectric performance with liquefaction and environmental properties. To reveal the inherent correlations between dielectric strength (Er), boiling point (Tb), and global warming potential (GWP) of dielectric materials, a coupled structure‐activity relationship (CSAR) model has been proposed for the first time. By means of the generic descriptors, as deduced from the electrostatic potentials, and the specific descriptors, as introduced from the respective microscopic mechanisms, the complex interdependence between Er, Tb, and GWP of the insulation gases is quantitatively characterised by the 3‐D coupling matrix. The coupling mechanism for the right balance of properties is uncovered in terms of the first‐principle descriptors. The CSAR model outperforms the previous SAR models in predicting Er, Tb, and GWP simultaneously in a self‐consistent manner. More importantly, the concept of CSAR could be extended readily to any multidimensional macroscopic properties. Novel replacement compounds have been identified tentatively to be the promising candidates to replace SF6 using the CSAR model.

Abstract Ultra‐wideband (UWB) microwave sources driven by specialised pulsed power generators have experienced a considerable development in the last decade due to their wide domain of new applications such as defence or counter‐terrorism activity. The authors present the main findings of a research dedicated to the development of a pulsed power‐driven electromagnetic field source for disabling improvised explosive devices (IED). The pulsed power generator driving the source is a 13‐stage compact Marx producing voltage pulses reaching an amplitude of 0.5 MV, with a pulse repetition frequency (PRF) of up to 100 Hz. The generator is coupled to a bipolar pulse forming line, providing bipolar pulses with a dV/dt of around 1.6 MV/ns. This pulsed power system feeds an array composed of 16 Koshelev‐type UWB antennas through an impedance matching transformer. The resulting electromagnetic source is capable to produce pulsed electric fields (PEFs) having a figure‐of‐merit (FOM) of 1 MV. First, practical experiments were carried out to study the effects of the PEFs on targets. The targets used in the present study are M2B type flashbulbs, known to have the same susceptibility as the US army M6 detonator. Different configurations of wires (shielded, twisted, etc) with different lengths were used in connecting items inside these targets. The tests were performed by placing the flashbulbs at different distances to determine the essential parameters (i.e., amplitude, duration, and frequency range) of the PEFs required to trigger them. An overview of the experimental campaign and the main findings are also presented followed by conclusions.

Abstract During the operation of high‐voltage cables, external stress and residual stress can affect the aggregated structure of insulating materials and lead to significant deterioration in their electrical performance. To investigate the evolution characteristics of the electrical properties of cross‐linked polyethylene (XLPE) under mechanical stress, this paper explains the relationship between the aggregated structure of XLPE and its electrical properties and proposes a method for improving insulation performance under mechanical stress. The results show that metallocene polyethylene used as a nucleating agent can promote crystallisation through heterogeneous nucleation and increase Young's modulus by non‐uniform nucleation, increasing crystallinity and reducing interplanar spacing, resulting in more complete crystal forms and reduced damage to the aggregated structure during the tensile process. After nucleating agent modification, the XLPE crystallisation becomes more uniform, and interfacial adhesion forces increase. The weakened interface damage process between the amorphous and crystalline regions under tensile stress effectively inhibits the process of molecular chain polarisation turning and reduces trap density. The modified XLPE crystal structure shows a tendency towards densification and enhanced molecular chain interactions, which can reduce the damage to the aggregated structure under tensile stress, while the reduced free volume inside the material and the shortened average free path of carriers can weaken the damage of high‐energy electrons to molecular chains, thereby inhibiting the process of electrical tree degradation. The results show that nucleating agents have great potential for maintaining the stable operation of XLPE cables under mechanical stress.

Abstract Owing to advanced power electronic and electrical applications developing towards miniaturisation and integration, the thickness‐dependent DC breakdown mechanism of epoxy/multiwall‐carbon‐nanotube nanocomposites is under investigation. The results indicate that the breakdown strength of nanocomposites containing 0.05 wt% multiwall‐carbon‐nanotubes rises by ∼18%, and the breakdown strength falls exponentially with increasing thickness. To clarify the microscopic mechanism, a simulation model of DC breakdown, including carriers transport and segmental dynamics, is developed, and the accordant simulation results with experimental results indicate that the thickness‐dependent DC breakdown of epoxy/multiwall‐carbon‐nanotube nanocomposites is determined both by segment chain dynamics and charge transport. According to the breakdown model analysis, the effects of multiwall‐carbon‐nanotube on enhanced breakdown strength are caused by the increased amount of deep traps in the interfacial region, while the influence of thickness is attributed to the enlarged segment chain displacement and electric field distortion as the voltage raising time increases.

Abstract Transformers may suffer multiple short‐circuit impacts during long‐term operation, and axial instability is one of the typical types of serious accidents caused by short‐circuit faults. The axial instability form of the winding‐block structure is analysed, and the dynamic solution of the winding short‐circuit electromagnetic force is obtained by establishing the three‐dimensional magnetic‐circuit‐force multi‐physical field coupling simulation model. The influence of strain rate on the cushion block constitutive equation is corrected, and the modified model is verified by short‐circuit impact test and quasi‐static test. The research results show that for 110 kV 31.5 MVA transformers, the maximum electromagnetic axial resultant force of winding is 363.16 kN, and the ultimate tilt force is 1214.2 kN. The pre‐tightening force configuration is accordingly recommended to range from 363.16 to 608.28 kN, which is narrowed by 18.49% compared with the static calculation method; Meanwhile, adding a logarithmic strain rate correction term to the classical constitutive equation of the cushion block can achieve a good correction of the stress‐strain relationship with the coefficient of determination above 0.99, and the cushion block has a larger elastic modulus under high strain rate load. The research results provide an important theoretical reference for the axial stability structure of transformers.

Abstract The surface charge accumulation on the basin insulator is a particular problem in high‐voltage direct current (HVDC) gas insulated switchgears (GIS) and gas insulated transmission lines (GIL), which restricts the development and application of extra/ultra high‐voltage (EHV/UHV) technology. The surface charge distribution and anti‐flashover performance are closely related to the insulator shape. To obtain the optimal basin insulator, a shape optimisation model based on artificial bee colony algorithm was established, and the minimisation objective functions based on capacitive (initial) electric field distribution and resistive (steady‐state) electric field distribution were respectively constructed. The optimisation results of the two objective functions were calculated, and the electric field and charge distribution on the surface of the insulator before and after optimisation were evaluated and compared using the simulation model. The results indicated that the optimisation based on the capacitive electric field can significantly inhibit the surface charge accumulation, and the optimised insulator can significantly reduce the surface normal electric field and make the distribution of the tangential electric field more uniform, and the maximum tangential electric field can be reduced by 10%; the optimisation based on resistive electric field can achieve similar results, but requires more computational resources. Based on the results, the ‘anti‐charge’ basin insulator structure suitable for the DC field was given.

Abstract The semi‐conductive shielding layer is an important part of the high‐voltage cable, playing a role in uniform electric field and reducing the air gap at the interface. The overall performance of the cable is affected by the semi‐conductive shielding layer with different base resin composition. The matrix resins of ethylene‐vinyl acetate (EVA), ethylene‐ethyl acrylate (EEA) and ethylene‐butyl acrylate (EBA) were used to prepare the semi‐conductive shielding materials of CB/EVA, CB/EEA and CB/EBA. The influences of different matrix resins on the chemical, electrical, thermal and mechanical properties of the shielding materials were investigated. The results show that CB has the best dispersion in EBA resin and the worst dispersion in EEA resin. The temperature inflection points of CB/EVA, CB/EEA and CB/EBA shielding materials are 90°C, 100°C and 110°C, respectively, and the CB/EBA shielding material has the lowest resistivity and the weakest positive temperature coefficient effect at room temperature. The thermal conductivity of all three matrix resins is smaller than that of the shielding material, the thermal conductivity of CB/EVA and CB/EBA shielding materials show a slow increase with temperature, and the CB/EEA shielding material is the least affected by the temperature. The mechanical properties of the three matrix resins and the three shielding materials are EBA > EVA > EEA, among them the stress of CB/EBA shielding material is 31.0 MPa and the strain is 570%. This work has important reference significance for the selection of shielding layer matrix resin and material formulation in engineering applications.

Abstract Vibration with a frequency of 100 Hz is widely distributed in the power equipment, and it can provide a new way to supply energy for sensors by vibration energy harvesting. The vibration energy harvesting method based on electromagnetic induction principle was studied through the arrayed structure of magnets and coils. Static magnetic field models were established for four magnet array structures and it was found that the alternating magnet array has the largest magnetic flux and magnetic flux gradient. Based on the alternating magnet array, prototypes of energy harvester with vertical and parallel movement mode were proposed. Through structural parameter optimisation analysis, two different energy harvesters were fabricated and it was found that the energy harvester with a parallel movement mode has better output performances. The energy harvester could provide output voltage/current and power of 8.35 V/17.39 mA and 15.13 mW (matched resistance is 200 Ω) at an acceleration of 5 m·s−2. The 100 mF capacitor could be charged to 2.72 V within 300 s, and the final voltage of the capacitor is greater than 3 V, which could sustainably drive commercial wireless temperature/humidity sensors.

Abstract Because DC conductivities of oil‐paper materials can be easily affected by electric field and temperature, the electrical properties under electro‐thermal coupling of oil‐paper materials should be considered when optimising the insulation structure of valve‐side winding of the converter transformer. Based on the finite element multi‐physical field coupling simulation, the multi‐objective optimisation of main insulation structure of valve‐side winding is carried out. In view of the high time consuming of multi‐physical field calculation and the actual needs of an insulation structure optimisation, the Kriging method and technique for order preference by similarity to the ideal solution (TOPSIS) method are introduced, and combines them with NSGA‐II to obtain a joint algorithm that can be used for the optimisation of insulation structure of the converter transformer. By using the joint algorithm of multi‐objective optimisation, the insulation structure configuration scheme of valve‐side winding is optimised. It can be seen from the experiment result that, on the one hand, the joint algorithm adopted can obtain the insulation structure configuration scheme that meets the design requirements. On the other hand, when facing the configuration scheme optimisation under multi‐field coupling, the computational time required by this method is only 0.15 % of that required by original genetic algorithm.

Abstract A dual‐frequency (DF) dielectric barrier discharge, excited by the superposition of a 50 Hz low frequency (LF) and a 5000 Hz intermediate frequency (IF), is proposed to enhance discharge. The effect of the LF voltage component on the breakdown behaviour of the DF discharge during different periods has been studied both experimentally and numerically. The number of high‐current pulses rises as the LF voltage increases. The statistical analysis shows that the number of the current pulse amplitude above 80 mA in the DF discharge reaches nearly 6 times that in the IF discharge. Additionally, the total discharge energy in the DF discharge is significantly higher than that in the IF discharge. The simulation reproduces the temporal variation of the breakdown behaviours in the DF discharge. The simulated results reveal that the maximal electric field strength of the breakdown process is greater in the DF discharge compared to the IF discharge during a half‐period of DF. Finally, the comparison between the IF and DF discharges exhibits that the LF voltage regulates the accumulation of residual charged species on the dielectric surface after the breakdown by modulating the residual voltage between the air gap.

Abstract Condition monitoring of the insulating system within power transformers has a massive importance according to the electrical utilities. Dissolved gas analysis (DGA) is frequently used for this purpose. However, DGA lacks the necessary level of accuracy to identify all equipment faults, particularly in their initial stages of degradation. Also, it does not have the capability for real‐time monitoring and relies on manual sampling and laboratory testing, causing potential delays in fault identification. Additionally, the interpretation of DGA data necessitates specialised expertise, which may pose difficulties for smaller entities that have limited access to resources. Therefore, the contribution of this research is to use infrared spectroscopy measurements as a new effective technique substituting the DGA method for fault diagnosis in insulating oil. The inception faults that were considered in this study were the electrical fault (discharges of high energy) and the thermal fault (300°C

Abstract The moisture generated by the ageing of the oil‐paper insulating system can easily lead to the deterioration of the performance of the insulating paper. In order to alleviate the impact of moisture on the performance of the insulating paper, we developed a kind of lipophilic hydrophobic self‐repairing cellulose insulating paper (new insulating paper) based on the ternary system of polytetrafluoroethylene, fluorocarbon surfactant and fluorinated alkyl silane, and accelerated thermal ageing test for 45 days at 130°C was carried out. The experimental results show that the new insulating paper with excellent lipophilic property can realise hydrophobic self‐repairing through heat treatment after physical damage. The tensile strength and elongation at break of the new insulating paper increased by 5%–8% and 6.25%–27% respectively compared with the original cellulose insulating paper. At the end of ageing, the relative dielectric constant and dielectric loss factor of new insulating paper are 10.4% and 9.9% lower than that of the original cellulose insulating paper, while the breakdown voltage is 6.8% higher. The acid and moisture content produced during the ageing process of the insulating oil impregnated with new insulating paper are also less, indicating that the coating can delay the ageing of the insulating paper.

Abstract Insulation systems in high‐voltage electric machines play a pivotal role in the reliable operation and longevity of the equipment. Mica‐based insulation materials have proven to possess and maintain excellent dielectric properties in the long run and prevent premature insulation degradation. Numerous qualifications tests, such as voltage endurance, are outlined in IEC and IEEE standards. The authors, however, take a different parametric approach, opting for reliability assessment of insulation systems using derived three‐parameter Weibull models. Therefore, instead of simple pass–fail criteria, empirical data is employed to determine failure rate probabilities quantitatively and objectively. Experimental data, including breakdown, dissipation factor, and partial discharge measurements, are used to construct the Weibull distribution model to predict fault and failure rates and calculate hazard functions. The rigorous examinations interpreted through the analytical model help assess insulation system resilience and particularly the impact of electrical field stress and mica content. Variation of electrical stress from 66.75 to 71.20 V/mil demonstrated how the mean time to failure of the system changed from 146.4 to 85.1 at 3 Un, hence identifying opportunities for design improvement and uncovering performance boundaries. Ultimately, the developed framework enhances comprehension of insulation system failure probabilities, guiding design decisions and ensuring a secure and reliable operation of electrical machines across applications.

Bagi pejalan kaki, kebiasaan menyebrang jalan menggunakan zebra cross menjadi hal yang sangat sering dilakukan, terlebih bagi mereka yang tinggal didalam pusat perkotaan dan tidak memiliki kendaraan pribadi, ataupun mereka yang sering menggunakan transportasi umum sebagai mobilitasnya. Namun, beberapa pengendara masih tidak memiliki kesadaran dan tidak mengurangi kecepatan berkendara ketika ada pejalan kaki yang ingin menyebrang. Hal ini yang mengakibatkan kekhawatiran bagi pada pengguna zebra cross ketika hendak menyebrang. Untuk memberikan rasa aman kepada pejalan kaki, fasilitas zebra cross dapat dipadukan dengan pelican crossing. Akan tetapi, pelican crossing sering menjadi sasaran tindakan tidak bertanggung jawab dari beberapa individu yang dapat menyebabkan kerusakan pada fasilitas tersebut. Selain itu, banyak pelican crossing rusak yang tidak segera diperbaiki, sehingga menimbulkan potensi bahaya bagi pejalan kaki dan pengguna jalan lainnya. Berdasarkan masalah ini, penulis bertujuan membuat portable pelican crossing menggunakan komunikasi nirkabel ESP-Now. Dari penelitian ini Portable Pelican Crossing dapat di operasikan dengan jarak optimal maksimal 25 meter dan jangkauan jarak dapat diperluas hingga 50 meter dengan risiko proses pengiriman data menjadi terganggu.

Sistem navigasi udara sangat penting bagi pergerakan pesawat yang aman dan efisien, serta memberikan panduan penting selama berbagai fase penerbangan. Doppler VHF Omnidirect Range (DVOR) adalah perangkat navigasi yang diperlukan dan memiliki kemungkinan tak terbatas untuk mengarahkan pesawat ke bandara. Efek Doppler adalah pendekatan penelitian yang digunakan dalam penelitian ini. Proses pengiriman informasi frekuensi yang dipancarkan DVOR ke pesawat menghasilkan frekuensi yang berbeda-beda akibat adanya efek Doppler yang disebabkan oleh sudut datang pesawat sehingga gelombang yang dihasilkan tidak berbentuk sinusoidal yang terlalu sempurna, namun frekuensi DVOR akan menghasilkan 112299595 Hz, dengan membentuk sistem OBS pada pesawat yaitu 187 derajat yang artinya menunjukkan posisi suatu bandara.

Dengan majunya perkembangan teknologi beberapa tahun terakhir, menghadirkan banyak konten digital. Hal ini juga menghadirkan kesempatan dalam bidang penelitian seperti halnya Machine Learning. Salah satu metode dalam Machine Learning adalah klasifikasi. Klasifikasi bertujuan untuk mengelompokkan data sesuai dengan kelasnya. Akan tetapi faktor seperti data imbalance dapat menyebabkan hasil dari metode ini menjadi kurang sesuai dengan yang diharapkan. Penelitian ini menyajikan tinjauan komprehensif tentang metode klasifikasi dalam pengolahan teks, dengan fokus pada penanganan tantangan yang ditimbulkan oleh data yang tidak seimbang. Dengan pertumbuhan eksponensial konten digital, kebutuhan untuk mengkategorikan dan menganalisis data teks secara efektif telah menjadi semakin kritis. Metode klasifikasi memainkan peran penting dalam upaya ini, memfasilitasi tugas seperti analisis sentimen, klasifikasi dokumen, dan pengambilan informasi. Namun, keberadaan data imbalance, ditandai oleh distribusi kelas yang condong, menimbulkan hambatan signifikan terhadap keandalan dan efektivitas model klasifikasi. Dengan penelitian ini diharapkan pembaca, dapat mengetahui metode apa saja yang umumnya digunakan dalam metode klasifikasi. Kemampuan metode klasifikasi tersebut pada umumnya ketika dihadapkan pada kasus tertentu seperti data imbalance. Tinjauan ini menyoroti Support Vector Machine (SVM) sebagai metode klasifikasi paling menonjol sebesar 25%, diikuti oleh K-Nearest Neighbours (KNN) dan Random Forest dengan persentase 19%, Decision Tree, dan Naïve Bayes. Metode alternatif yang disesuaikan dengan tujuan penelitian dan tantangan tertentu juga dieksplorasi. Hasil persentase penggunaan metode tersebut didapat dari kumpulan jurnal yang peneliti kumpulkan dan teliti

Sistem Komunikasi Antar Arduino menggunakan Protokol RS485 dirancang untuk mendukung komunikasi jarak jauh hingga 1200 meter, walaupun pada percobaan digunakan kabel dengan panjang sekitar ±25cm. Komponen sistem melibatkan mikrokontroler master sebagai pusat kendali yang mengirimkan perintah kepada mikrokontroler slave dan mengakses input dari push button, hasilnya ditampilkan pada layar LCD. Mikrokontroler slave berperan dalam menerima dan menjalankan perintah dari mikrokontroler master, dengan data terkait aliran daya listrik pada masing-masing slave (880 watt pada slave 1, 900 watt pada slave 2, dan 800 watt pada slave 3).