Voltage Circuit Research Articles

Challenges in Microgrids with Medium Voltage Circuit

This paper presents and discusses challenges in microgrids (uGrid) that arise when they operate isolated from the main grid. Specifically, these challenges occur because the system becomes an ungrounded delta configuration, and the microgrid power sources exhibit low short-circuit capacity. The important issues addressed include the failure to detect ground overcurrent during an earth fault event, voltage imbalances recorded by voltage transformers (VTs) connected between phases and earth, and the phenomenon of ferroresonance. These issues directly impact the coordination of electrical protection, component integrity, and synchronization checks between different power sources within the uGrid. Therefore, the Energy Management System (EMS) is tasked with managing protection devices and systematically responding to minimize disruptions, thereby ensuring operational security. This paper examines the protection functions within devices for both operational modes (on-grid and off-grid) and the corresponding decisions implemented as rules within the EMS. Effective coordination between protection devices and management systems ensures a rapid and selective response to faults, thereby enhancing microgrid security and facilitating efficient problem detection and resolution.

Towards all inorganic antimony sulphide semitransparent solar cells

NiO, a wide band gap hole-transporting material (HTM), is gaining attention in photovoltaics due to its optical transparency, chemical stability, and favourable band alignment with absorber. This study uses NiOx nanoparticle-based HTM in semi-transparent Sb2S3 solar cells via a simple chemical precipitation method. We optimised NiOx layer by varying precursor solution concentration and studied its impact on optical and structural properties, composition of nanoparticles and subsequent effect on the performance of semi-transparent Sb2S3 solar cell. NiOx nanoparticles, deposited from nickel(II)nitrate hexahydrate (precursor solution concentrations of 0.2 M to 1.2 M), were thermally treated by two steps at 90 °C for 6 h and 270 °C for 3 h. Nanoparticles with crystallite sizes of 6–9 nm had band gaps (Eg) of ca. 3.65–3.70 eV. Using 1.2 M concentration yielded the largest crystallites (9 nm), lowest Eg (3.65 eV) while retaining the most precursor residues. The highest power conversion efficiency (2.68%) was achieved with NiOx from a 0.5 M precursor, a 60% improvement over HTM-free cells. The effect of precursor solution concentration on the solar cell parameters (efficiency, fill factor, open circuit voltage and short circuit current) are discussed. Present work paves a path toward stable, efficient, and cost-effective all-inorganic Sb2S3 solar cells using NiOx HTM instead of organic counterparts.

A High-Precision Curvature Compensation Reference Circuit for a Cable Accessory Image Acquisition Device

High-voltage cables are widely used in power transmission and distribution systems, and their accessories (such as connectors, terminals, and insulators) are key parts to ensure the safe and reliable operation of power systems. These accessories may be affected by factors such as temperature, humidity, and mechanical stress during long-term operation, resulting in performance degradation or failure. In high-voltage environments, performance monitoring of cable accessories is crucial. The reference voltage circuit can withstand the influence of temperature changes and power supply fluctuations, support accurate current and voltage measurement, and thus detect potential faults in time to ensure the safe and stable operation of the power system. However, the traditional reference voltage circuit has a low-temperature curvature loss, which results in an inaccurate reference voltage, resulting in equipment damage. Therefore, in order to solve the problem of curvature loss in this part, this paper proposes a curvature compensation circuit, which realizes a high-precision reference voltage circuit through a high-temperature curvature compensation circuit, thereby meeting the current reference voltage requirements for cable accessory monitoring.

Voltage Controlled Oscillator Realisation with Temperature and Source Independent Circuits

In this article, a square wave was generated with a voltage-controlled oscillator circuit (VCO) using a bandgap reference voltage circuit and a low drop-out (LDO) circuit. The band gap reference circuit can generate a constant 500mV voltage between -40⁰C and +125⁰C. The LDO circuit is driven by a bandgap reference voltage circuit and exhibits a stable output even at different voltage levels. The last circuit, VCO, is driven by the LDO circuit. It can generate square waves between 1200MHz and 1600MHz at the output. Simulations using 130nm TSMC technology parameters have been successfully achieved.

Stress analysis and structural optimisation of insulating rods under dynamic and static loads

AbstractThis study aims to provide a theoretical basis for the fatigue characteristics and structural optimisation of insulating rods to enhance their reliability and lifespan in practical applications. This paper uses COMSOL to complete the stress analysis of insulating rods under dynamic and static loads based on the finite element method. The correctness of the model is verified based on the elastic‐plastic theory. The simulation results show that under the same load, the stress concentration area is more affected by the dynamic load, and the stress concentration position is highly consistent with the fracture position of the rod in the experiment. It verifies the impact on the insulating rods at different speeds and static load stress. Simulation shows that, in cases where the allowable stress is exceeded, as the number of operations increases, the fatigue characteristics will greatly affect the service life of the insulation rod. Finally, the fatigue analysis and structural optimisation of the insulating rod were completed, providing important reference values for the long‐term stable operation of ultra‐high voltage circuit breakers.

Optimized leakage control in CMOS NAND gates: the in-triggering technique

Abstract Leakage power, now the largest contributor to integrated circuit power consumption, is rising quickly, according to the International Technology Roadmap for Semiconductors (ITRS). As CMOS (complementary metal-oxide semiconductor) technology continues to shrink to deep submicron levels, gate leakage and subthreshold have become important components that contribute to total power dissipation. To address this problem, many methods have been put forth, especially at the circuit level. In 45 nm CMOS, variability and short-channel effects limit noise margins and compromise gate delays, thereby compromising the timing closure and robustness of ultra-low voltage circuits. The resulting supply voltage guardband may reduce energy efficiency in order to achieve a reasonable production yield. Furthermore, the high leakage currents of these technologies decrease energy efficiency when idle intervals are prolonged. In this study, two designs of a novel two-input NAND gate at 45 nm CMOS technology are constructed using eight transistors (8-T). A novel circuit technique named "In-Triggering (INDEP with Bi-Triggering)" is presented in this study with the goal of lowering subthreshold leakage in digital circuits. This method is thoroughly contrasted with other leakage reduction strategies now in use, such as Base, Sleepy LECTOR, LECTOR, INDEP, and Bi-Triggering procedures. Evaluation is done using key performance measures such power-delay product (PDP), latency, subthreshold leakage power, and total power consumption. 45-nm Predictive Technology Models (PTM) with a nominal supply voltage of 1V are used in the investigation. According to our findings, the suggested In-Triggering technique outperforms the conventional NAND gate in terms of speed by 12% and significantly reduces leakage power by up to 56%. Furthermore, compared to the Base, Trig01, and INDEP NAND gates, the method offers mean power savings of 58.8%, 36.1%, and 30.7%, respectively. At supply voltages of 1V, a comprehensive comparison and verification are then conducted utilizing the several proposed and existing methodologies. The effectiveness of the In-Triggering technique in reducing leakage power in CMOS circuits is confirmed by comparing these results to the most well-known design strategies for both active operation and sleep modes.

Novel Indoor Educational I-V Tracer for Photovoltaic Modules

The renewable energy market, particularly the photovoltaic sector, has experienced significant growth over the past decade. Higher education institutions must play a vital role in the training of professionals, which the sector is currently demanding and will continue to require in the future. A pivotal resource for understanding the performance of PV modules is the experimental extraction of the characteristic I-V curve in laboratory practices. This paper presents an innovative and low-cost I-V curve tracer which can be used in indoor laboratories for teaching purposes. The described measurement system presents the novelty of helping form an energy-harvesting IC to force a sweep of the voltage from values close to zero to the open voltage circuit (Voc). An Arduino Micro board interfaces the implemented electronics and a LabVIEW-based monitoring and control program. The system proved its reliability and accuracy when it was compared to a calibrated commercial I-V tracer. The experimental results show that for a low-power PV module illuminated by a lamp, the proposed I-V tracer only deviated 1.3% from the commercial one in measurements of the maximum power.

Optimizing the CBO for Improved Performance in the PBDB-T: ITIC Organic Photovoltaic Cell

Renewable energy sector should have power generation system which are environmentally friendly as well as ecofriendly. In respect of this we present theoretical and simulation-based study of an organic solar cell with the absorber layer PBDB-T and ITIC blend. Transportation of photogenerated charge carriers in the solar cells plays vital role in determining the performance parameters of the cells. In view of improving the charge carrier transportation in the proposed solar cell we propose conduction band optimization (CBO) method. Further the impact of the physical parameters such as temperature, series and shunt resistances are also observed for the better understanding of the performance of the proposed solar cell device. All the work presented is performed via the SCAPS 1d simulation software. First, the conduction band optimization is done by the realization of the electron affinity of all the layers of the proposed solar cell. The CBO optimization shows that the proposed cell can have best performance with the efficiency of 21.73%. This optimum performance of the cell obtained at the 3.8eV electron affinity of the absorber layer. Moreover, the physical parameters optimization revealed the suitable condition of superior performance. The appropriate physical conditions are obtained as series and shunt resistances of 3.5 and 1000 Ωcm2 at temperature of 300K. The optimum performance is as power conversion efficiency (PCE) of 17.39%, fill factor (FF) of 65.61% with the open circuit voltage (Voc) and short circuit current (Jsc) of 0.9561 V and 27.72 mA/cm2 respectively. This shows the best performance in the organic family of photovoltaic cells.

Development technology of helium neon laser power supply

The Helium-Neon (HeNe) laser is one of the most commonly used gas lasers in many spectroscopic applications. It is a visible laser with a typical wavelength of 632.8 nm. The best part is, due to its low cost and simplicity, it is popular among hobbyists as well. The output power of a practical HeNe laser tube is usually less than 1mW. In order to operate the HeNe laser, it requires a few kilovolts of direct current (DC). The necessary high voltage DC is generated by a HeNe laser power supply. A typical HeNe laser power supply is a complex, high voltage circuit which is designed to provide the gas discharge current, as well as to maintain the helium and neon mixture within the laser tube at an optimal pressure and temperature. There are many existing laser power supply designs. Therefore, the objective of this design project, "Development of Helium Neon Laser Power Supply" is to design and construct a HeNe laser power supply which is low cost, efficient, light in weight and most importantly, to develop a high voltage DC power supply circuit which can be used to power the HeNe laser. Through this design project, a comprehensive and systematic study from the analysis of the existed laser power supply designs to the performance testing of the developed HeNe laser power supply has been carried out. The use of organic electro-optic material for electro- optical applications was suggested many years ago. Many devices have been developed since then, but some of them have been examined for their electro- optic response. Due to the many and important uses of radioactive isotopes in medical and industrial applications, it became necessary to evolve materials that are used in protection. [1] [2] [3] [4] [5].

Development of a control algorithm for a boost converter with the possibility of dynamic correction of control system parameters

RELEVANCE of the study lies in the development of an algorithm for controlling a DC voltage converter capable of providing a high-quality transient process with a wide change in the input parameters of the control object, affecting its nonlinear properties. purpose. THE PURPOSE. To consider methods for the development of continuous and discrete control systems for a step-up DC voltage converter and to obtain an analytical dependence of accounting for the nonlinear properties of the converter that affect the quality of regulation of the output voltage of the voltage stabilizer METHODS. The method of the average geometric root was chosen as a method for calculating the coefficients of the DC voltage converter control system, and the current circuit is adjusted using the technical optimum method, and the voltage circuit using the symmetric optimum method. The obtained analytical solutions of mathematical models and simulation models were compared in the SimInTech software environment. results. RESULTS. The simulation results show that the analytical solution of the mathematical model of the voltage stabilization system has a shorter transition time than the simulation results. This is due to the fact that in the mathematical model according to which the continuous control algorithm was synthesized, the presence of a power input filter, as well as the degree of their precharge, is not taken into account. Because of this, the transition time on simulation models is slower, applied 4 times than in the mathematical model. conclusion. CONCLUSION. When comparing the algorithms with each other, it can be seen that the algorithm obtained by converting a continuous algorithm by the Tusten method has the shortest transition time than all other algorithms. The continuous algorithm and the algorithm obtained by the inverse Euler transformation method have a speed close to each other, and the algorithm obtained by the direct Euler transformation turns out to be the slowest.

A fusion algorithm of multidimensional element space mapping architecture for SOC estimation of lithium-ion batteries under dynamic operating conditions

A fusion algorithm of multidimensional element space mapping architecture for SOC estimation of lithium-ion batteries under dynamic operating conditions

Research on high voltage circuit breaker multi-sensor signal feature selection method based on GA-Kmeans algorithm

Abstract Currently, in the research on fault information of high-voltage circuit breakers (HVCBs) based on multi-sensor data, issues such as shallow feature assessment and unclear feature selection rules exist, leading to a decrease in fault identification accuracy due to redundant characteristics. To address this, this paper proposes a novel feature selection method based on GA-Kmeans. This method encodes the original feature space into binary format and employs the clustering accuracy of the Kmeans model as the fitness function to obtain a high-quality feature subset that maximally represents and distinguishes faults. By combining different feature selection methods with fault diagnosis models, six typical application scenarios are constructed. Results indicate that compared to traditional methods such as Relief-F, KPCA, GA-SVM for feature selection, and SVM for fault diagnosis, the proposed GA-Kmeans method reduces the dimensionality of the original feature space and employs the Kmeans clustering algorithm as the diagnostic model, achieving a final diagnostic accuracy of 95.29%. This method outperforms others, with a 37.24% higher diagnostic accuracy than SVM under the original feature space, and a decrease of 47.90% in standard deviation. This validates the necessity of feature selection and the superiority of the proposed method, providing a reliable and stable diagnostic basis for subsequent mechanical fault diagnosis of HVCBs.

Research on key circuits of high‐precision servo channel loading card for wing fatigue testing

AbstractThe key circuits of servo channel loading card with high‐precision data acquisition and output functions for wing fatigue testing are studied and improved in this paper. To solve the problem of large offset voltage in some op‐amps, non‐inverting combined amplifier circuit (NCAC) and inverting combination amplifier circuit (ICAC) are proposed by utilizing precision op‐amps combined with wide voltage and high‐power output op‐amps. In the force signal acquisition section, a non‐inverting combined zeroing filter circuit (NCZFC) is proposed to improve the precision of signal acquisition. In the excitation source output section, a non‐inverting combined excitation output circuit (NCEOC) is proposed to improve the precision of the positive excitation output; an inverting combined excitation output circuit (ICEOC) is also proposed, which improves the precision of the negative excitation output and also realizes the inversion of the input and output signals. In the servo drive output section, a non‐inverting combined voltage and current conversion circuit is proposed to improve the precision of voltage and current outputs, which has two modes of non‐inverting combined voltage output (NCVO) and non‐inverting combined current output (NCIO) modes. Simulation experiments in Multisim and actual tests have been carried out on the above improved circuits to verify the stability and precision.

Integrating Intelligent Sensors for Safe UAV Distribution: Design and Evaluation of Ranging System

In our increasingly electrified society, electricity has become indispensable to both production and daily life. However, high-load electric energy transmission presents inherent safety risks. To ensure the secure transportation of electric energy, live work on distribution networks is essential. However, traditional live work techniques require a high level of dependence on worker experience, which frequently leads to inaccurate safety distances and degrades worker security. This study proposes the integration of Unmanned Aerial Vehicles (UAVs) with intelligent robot sensing technology to enhance safety and efficiency in live work. By accurately measuring safety distances, UAVs offer a promising solution to mitigate risks associated with high-voltage circuits. Comparative analysis between traditional and intelligent live work safety distance measurements reveals the two live works under the high voltage circuit were 92% and 96%, respectively, and the accuracy of the two live work safe distance measurements under the low voltage circuit was 84% and 99%, respectively. Results demonstrate that UAVs equipped with intelligent sensing technology achieve superior accuracy in safe ranging for live work, thereby ensuring stable energy transmission and safeguarding the lives of workers in distribution networks. Doi: 10.28991/HIJ-2024-05-03-04 Full Text: PDF

Hi‐Z fault location identification on low voltage distribution systems using IoT‐based digital twin model computation

AbstractDistribution feeders carry and supply power to industrial, commercial and residential loads from the point where sub‐transmission (33 kV level) ends after stepping down to suitable voltages, such as 11 kV and further down to 400/230 V. In recent times, high impedance (Hi‐Z) faults on distribution systems are creating unique challenges to utilities both from operational and safety perspectives. Most of these Hi‐Z faults occur at distribution voltages of 15 kV or below, with the problem being worse at lower voltages. Hi‐Z fault detection technologies emerged and were developed and incorporated on embedded platforms, such as relays, reclosers and sensors, which protect and monitor distribution systems. Although these technologies can detect Hi‐Z fault on feeders, most of them cannot identify the exact location of the fault. Specifically, there is no solution available in literature for detecting Hi‐Z fault location on low voltage (LV) circuits like 3‐phase 4‐wire 400 V distribution network. In this paper, we introduce a novel and a unique algorithm to identify the location of Hi‐Z faults using proposed smart metres IoT data‐based distribution system load flow and digital twin model representation of the network. Furthermore, a case study on the standard 33 bus LV system clearly depicts the functionality of the proposed algorithm.

Influence of different factors on gap breakdown process with hot electrode and high temperature gas medium in low voltage circuit breaker chamber based on particle-in-cell/Monte-Carlo collision simulation

Different factors such as gas composition inside the low voltage circuit breaker (LVCB) chamber and the residual plasma in the post-arc stage affect the breakdown process, which in turn affects the breaking capacity of LVCBs. In this paper, the effects of non-parallel electrode structure, gas temperature and pressure, electrode temperature, and gap distance on gap breakdown of hot electrode under high temperature gas conditions were studied, for which a particle-in-cell/Monte-Carlo collision simulation model has been established, which takes into account the effects of high-temperature gas components, cathode electron thermal emission, electron collision ionization and other effects, and simulation studies have been conducted. The simulation results show that the increase in gap gas temperature, the decrease in air pressure, and the increase in electrode temperature will lead to the gap breakdown more easily. With the increase in the gap length, the breakdown voltage increases, but the average electric field intensity required for breakdown decreases. In the non-parallel electrode structure, the breakdown occurs first at the position with the shortest gap distance, then the cathode sheath forms and extends along the electrode surface to other areas, and finally, the entire gap breaks down.

Mechanical State Fault Diagnosis Method of High Voltage Circuit Breaker Based on ICEEMDAN-Hilbert Marginal Spectral Energy Entropy

Mechanical State Fault Diagnosis Method of High Voltage Circuit Breaker Based on ICEEMDAN-Hilbert Marginal Spectral Energy Entropy

A repetitive pulsed electrothermal plasma jet ignition system based on capillary discharge.

Plasma ignition and combustion enhancement is a promising technology in applications of engines, industrial burners, pollutant emissions controls, etc. A new repetitive electrothermal plasma jet ignition system based on ablated capillary discharge under atmospheric pressure is presented in this paper. It consists of a capillary discharge module, a pulse current circuit, a pulse voltage circuit, a current release unit, an LC series resonant circuit, and a control system. The effects of the energy storage capacitor's voltage and resistance in the current release unit on the electrical parameters are investigated. Increasing the capacitor voltage helps to shorten the discharge delay and increase the energy deposition efficiency in the main discharge process. The increase of the resistance in the current release unit leads to a longer discharge delay and higher energy deposition efficiency in the main discharge process. Balanced parameters between the delay of discharge in 66 µs and the energy deposition efficiency in 84% are achieved through optimization, with a peak radiative heat flux of 23MWm-2 and a maximum jet length of 17cm. Repetitive capillary discharge at 20Hz under atmospheric pressure is achieved with the dispersion of energy storage capacitor charging voltage and energy deposition efficiency of 0.3% and 9.6%, respectively. Simplified circuit topology and control logic contribute to the miniaturization of the ignition system.

Mechanical fault diagnosis of high voltage circuit breaker using multimodal data fusion.

A high voltage circuit breaker (HVCB) plays a crucial role in current smart power system. However, the current research on HVCB mainly focuses on the convenience and efficiency of mechanical structures, ignoring the aspect of their fault diagnosis. It is very important to ensure the circuit breaker conducts in a normal state. According to real statistics when HVCB works, most defects and faults in high voltage circuit breakers is caused by mechanical faults such as contact fault, mechanism seizure, bolt loosening, spring fatigue and so on. In this study, vibration sensors were placed at four different locations in the HVCB system to detect four common mechanical faults using vibration signal. In our approach, a convolutional attention network (CANet) was introduced to extract features and determine which mechanical faults occur within a fixed period of time. The results indicate that the mechanical fault diagnosis accuracy rate is up to 94.2%, surpassing traditional methods that rely solely on vibration signals from a single location.

Ensembled methodology for the comtrade analysis regarding medium voltage side in wind park

Ensembled methodology for the comtrade analysis regarding medium voltage side in wind park