High-voltage Facilities Research Articles

Power Monitoring System Based on 4G Network Wireless Transmission

Abstract In order to solve the problems faced by high-voltage power facilities in the monitoring process, after comprehensively considering the characteristics of high-voltage transmission lines, regional environment, and other factors, a data monitoring system based on the perception layer of the Internet of Things is established. The system uses advanced IoT(Internet of Things) sensing technology, networking technology, and transmission technology to network data sub-nodes such as tower settlement, line galloping, and meteorology for information transmission. After the transmitted sensor information is fused and further processed, the overall judgment and early warning of the disaster area are formed.

부분방전 진단을 위한 초음파 계측 및 딥러닝기법의 응용

This paper presents an innovative diagnosis method for partial discharge which may damage the components of a high-voltage electrical equipment and cause power outbreak. Instead of using the conventional direct-attachment method, it is convenient to measure the arc noise produced by partial discharge from a safe distance. Then, the source signal is converted to a phase-resolved graph learned through the convolutional neural network. The proposed deep-learning scheme, after learning different phase-resolved graphs obtained from three types of partial discharges and environmental noises measured in the actual laboratory, exhibited a prediction accuracy of more than 94 % for the test samples. Therefore, if this technique is embedded on an ultrasonic camera, then a non-specialist like a gas inspector can easily diagnose the high-voltage facilities distributed over a broad area.

Teslametar za merenje magnetnog polja u visoko naponskim objektima

This paper presents a low-cost three-axis teslameter capable of measuring magnetic field intensity in industrial environments and high voltage facilities. It is based on an MFS-3A three-axis magnetic field sensor, and it can measure magnetic flux density up to ±5 mT in all three axes, with accuracy better than ±0.5% and excellent temperature stability. The proposed teslameter was calibrated using a state-of-the-art reference instrument, Helmholtz coil and temperature chamber. The paper describes the development and the calibration of the proposed teslameter. The obtained results are presented as well.

Pregled metoda za eliminisanje uticaja sistemske smetnje u aktivnom visokonaponskom postrojenju

In this paper, practical and conceptual problems related to the way of suppressing or eliminating the influence of interference (at a frequency of 50 Hz) in an active high-voltage power facility are discussed. The problem is relevant in the context of measuring the safety characteristics of the grounding system: grounding system impedance, touch voltage and step voltage. The paper gives an evolutionary overview of title methods. The review focuses on the characteristic problems and shortcomings of individual methods. Also, the basic characteristics of the author's FSM (Frequency Shift Method) method, which guarantees precise control of interference, are elaborated. In this sense, the FSM method is the basis for accurate and economical measurement of the safety characteristics of the grounding system.

A Method for Calculating of Нeating Closed High-Current Electric Contacts by Pulsed Currents

We propose an original method for numerical calculation of heating of high-current electric contacts in the closed state by pulsed currents with a duration comparable with the period of the industrial-frequency current. Such regimes are typical of current-carrying systems of high-voltage electric facilities during switching high-power loads, during failure in electric transmission lines, and in testing devices for stability to short-circuit current. In constructing the solution, we assume that the time dependences of the current and voltage across the contacts are known. We have developed an iteration procedure for solving a series of thermoelectric problems, which makes it possible to calculate the temperature distribution in contacts and to trace its variation by selecting the size of contact spots in each time interval. We have tested this method by comparing the results of calculation with experimental data obtained for cylindrical copper contacts heated to melting by pulsed currents in a wide range of contact pressure forces. The current actions are selected so that melting occurs during extremely short time (first quarter of the period).

The influence of stray inductance of storage capacitor and load capacitance on transients in high voltage facil-ities with pulse transformers

High voltage facilities based on gaining of voltage pulses by means of applying various types of pulse transformers are widely used in various engineering applications. Such high voltage facilities can be used for the elaboration of particle accelerators and in practice of forming pulses of high voltage for the purposes of electrical equipment testing. Technical characteristics of such high voltage facilities are significantly influenced by the technical characteristics of applied pulse transformer and, therefore, by the parameters of applied equivalent scheme of pulse transformer. Requirements to the obtained time dependencies of formed voltage pulses that arise in practice of testing high voltage insulation by applying pulses of high voltage demand to take into consideration the influence of parasitic parameters of equivalent scheme. This paper presents the results of consideration of the influence of parasitic inductances of storage capacitor and capacitance of tested object on currents in primary and secondary windings of pulse transformer. The influence of stray inductance on time dependence of voltage on load capacitance of tested object of control, as well as on time dependence of voltage on capacitance of storage capacitor is also considered. According to the results of carried out simulations, the inevitable parasitic inductance of tested object has more significant effect on time dependence of voltage on load capacitance than the parasitic inductance of storage capacitor.

Increasing the Electric Strength of a Vacuum-Insulated Tandem Accelerator

The electric strength of ceramic insulators was tested at a dedicated high-voltage vacuum facility and the electric strength of a vacuum-insulated tandem accelerator with redesigned feedthrough insulators was studied. Based on the results of the investigations and the upgrade the voltage in the accelerator was increased from 1.00 to 1.15 MV; the operating mode was achieved without high-voltage breakdowns.

Data acquisition system for capacitive energy storages

Failures in capacitive energy storages result in destruction of faulty elements and other expensive components. Recovery of such failures requires long-term and expensive works to replace and to restore elements of the capacitive energy storage. Diagnostic hardware of the capacitive energy storages makes it possible to limit the consequences of such failures, to reduce the frequency of their occurrence, as well as to monitor the equipment and transmit information on functioning of the pulse current sources to the facility. The operation of data acquisition system in high voltage facilities is accompanied by the electromagnetic interference, and it is therefore necessary to provide the optical fiber transmission lines, the isolation of the diagnostics hardware components and galvanic isolation of their power supply.

Separation of Partial Discharge Sources Measured in the High-Frequency Range with HFCT Sensors Using PRPD-teff Patterns.

During the last two decades, on-line partial discharge (PD) measurements have been proven as a very efficient test to evaluate the insulation condition of high-voltage (HV) installations in service. Among the different PD-measuring techniques, the non-conventional electromagnetic methods are the most used due to their effectiveness and versatility. However, there are two main difficulties to overcome in on-line PD measurements when these methods are applied: the ambient electric noise and the simultaneous presence of various types of PD or pulse-shaped signals in the HV facility to be evaluated. A practical and effective method is presented to separate and identify PD sources acting simultaneously in HV systems under test. This method enables testers to carry out a first accurate diagnosis of the installation while performing the measurements in situ with non-invasive high-frequency current transformers (HFCT) used as sensors. The data acquisition in real-time reduces the time of postprocessing by an expert. This method was implemented in a Matlab application named PRPD-time tool, which consists of the analysis of the Phase-Resolved Partial Discharge (PRPD) pattern in combination with two types of interactive graphic representations. These graphical depictions are obtained including a feature parameter, effective time (teff), related to the duration of single measured pulses as a third axis incorporated in a classical PRPD representation, named the PRPD-teff pattern. The resulting interactive diagrams are complementary and allow the pulse source separation of pulses and clustering. The effectiveness of the proposed method and the developed Matlab application for separating PD sources is demonstrated with a practical laboratory experiment where various PD sources and pulse-type noise interferences were simultaneously measured.

TRANSFER FUNCTION CENTERED PID TUNING IN CASCADED MULTILEVEL INVERTERS BASED ON PSO TECHNIQUE

Harmonic elimination in multilevel inverters nowadays a worthy talk in industries because of its high power and high voltage facilities. THD of the multilevel inverter should be reduced and a fundamental voltage component has been maintained. In this paper a new massive technique presented in the minimization of harmonics by calculating the transfer function of the eleven level cascaded multilevel inverter. The stability of the system also measured using Root locus, Bode analysis and assured the stability. Particle swam optimization (PSO) technique used to tune the parameters such as KP,KI,KD in closed loop control system. The optimization technique presented for a same DC sources. The software used in the paper is MATLAB Tool package. The transfer function and PID parameters were calculated by MATLAB software.

Electrical and Optical Characteristics of Si-Nanoparticle Films Deposited onto Substrates by High-Voltage Electrospraying from Ethanol Sols

The optical and electrical characteristics of films consisting of nanocrystalline silicon (nc-Si) deposited onto substrates by the high-voltage electrospraying of nc-Si sols in ethanol are investigated. It is found that the interaction of ethanol droplets carrying Si nanoparticles with a corona-discharge electric field leads to the polymerization of ethanol and the formation of a polymer layer on the Si-nanoparticle surface. A high-voltage facility for depositing the films using an additional focusing electrode allows one to change the geometry of the electric field and intensity in the region of the ethanol droplet flow. As a result, nc-Si films with qualitatively different properties of the polymer on the nanoparticle surface are formed, specifically, nc-Si_A and nc-Si_B, obtained without a focusing electrode and with it, respectively. Upon annealing at temperatures of up to 400°С, the optical band gap Eg of the nc-Si_A films increases from ~1.9 to ~2.2 eV, while the Eg value of the nc-Si_B films remains constant and amounts to 1.85 eV. The constant Eg value of the nc-Si_B films is explained by the properties of the polymer on the Si-nanoparticle surface and the more effective blocking of oxygen penetration from the surrounding environment upon annealing at temperatures of up to 400°C than in the case of a polymer in nc-Si_A films. The temperature dependences of the dark and photoinduced conductivity of nc-Si_A films are approximated with good accuracy by two activation-type exponential functions and the dark activation energies are ~0.75 and 0.1 eV, respectively. The conductivity of the nc-Si_A films noticeably decreases under irradiation of the samples at wavelengths of 460–470 nm. The temperature dependences of the conductivity of the nc-Si_B films are approximated with good accuracy by exponential functions with activation energies of 0.73 (in the dark) and 0.59 eV (under photoexcitation). In contrast to the case of nc-Si_A films, the photoconductivity of nc-Si_B films grows more than fourfold relative to the dark conductivity under analogous illumination. The nc-Si_B films are photoactive and sandwich-like Al/nc-Si_B/Al structures can generate a voltage. The dark conductivity and photoconductivity of the nc-Si_A films in the voltage range of V > 2 V are determined by the two-center Poole–Frenkel effect; the concentration of the centers affecting the Poole–Frenkel conductivity is ~3 × 1017 cm–3. In nc-Si_B films in the voltage range of 2–5 V, electron transport is determined by space-charge-limited currents and, at high voltages, by the two-center Poole–Frenkel effect. The concentration of traps contributing to the space-charge-limited currents is ~4 × 1016 cm–3. The concentration of Poole–Frenkel centers affecting the conductivity decreases according to the activation law with an activation energy of 0.7 eV from 3 × 1016 to 2 × 1014 cm–3 with a decrease in temperature from 120°C to 40°C.

Study on Design and Operation of High Voltage Facility for Power Quality Improvement

Study on Design and Operation of High Voltage Facility for Power Quality Improvement

Analysis of Reactive Energy Measurement Methods Under Non-Sinusoidal Conditions

The different methods of measuring the reactive power and energy for billing electricity consumers connected to medium and high voltage systems, presents different results in non-sinusoidal conditions. The purpose of the paper is to point out the imperfections of each method accepted by the legislation on measuring precisely the power absorbed by consumers. In this sense, the present work addresses the effect of the harmonic distortion of voltage and current in the measurement of reactive energy, considering the different existing measurement methods. Initially, the paper presents an analytical study covering modeling and computational implementations of each method available for the measurement of reactive energy. In addition, calibration tests were carried out considering different meter devices. Finally, considering a meter specifically developed in the context of the present work, a measurement campaign was applied in different medium and high voltage facilities in order to perform a practical comparison between the different reactive energy measurement methods. The results showed the need for a unification of reactive energy measurements methods in order to achieve isonomy in the billing process of electricity consumers.

Calculation of Low-Frequency Magnetic Field Distribution of a Transformer Station in Stationary State

This paper describes one way of assessment of exposure level to electromagnetic fields of secondary electronic equipment or personnel in or close to high-voltage facilities. Assessment of fulfilling criteria regarding allowable values of magnetic flux, according regulations, was gained by numerical calculation and experimental measurement, considering geometrical configuration of high-voltage facility elements. Correct identification of electromagnetic disturbances of transmission lines has for a result optimal geometrical disposition of electronic equipment inside a high-voltage facility. Comparing a calculation results and results of experimental measuring on particular example of high-voltage facility, can lead to a conclusion that expensive measuring can be avoided, through standardization of a mathematical model and through numerical calculation of low-frequency magnetic field distribution even in conditions of the most complex geometry. Having in mind a number of locations where interaction between high-voltage facility and electronic equipment and personnel exists, a clear intention of authors, for reducing expenses of recording interaction level, is visible.

Sliding-mode control of single input multiple output DC-DC converter.

Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

A literature analysis of power frequency electric field testing data

To analyze the literature on power frequency electric field testing data and to propose views and suggestions for current testing. The literature on power frequency electric field testing data published in the previous years was searched to identify 306 articles involving 193 valid testing data. Mann-Whitney test and Wilcoxon W test were used for analyzing the testing data. The classification of data was carried out according to one quarter of occupational exposure limit (1.25 kV/m), one half of the exposure limit (2.5 kV/m), and the exposure limit (5 kV/m). The structure of testing data showed a significant difference between the non-power facility group and the power facility group (P<0.05). As occupational hazard factors, the radiation exposure from power frequency electric field is extensive. However, the power frequency electric field testing data in actual workplaces except high-voltage power facilities are far less than the occupational exposure limit with little harmfulness. There is a phenomenon of excessive testing at present.

Energy transfer in the high-voltage electron cooler for the COSY synchrotron ring

An electron cooler produced by the Budker Institute of Nuclear Physics was put into operation at the COSY synchrotron (Julich, Germany) in 2013. This electron cooler has been designed for suppressing the effect of beam scattering by an internal target at energies as high as the maximum proton beam energy of 3 GeV. As the electron cooler was developed, many complicated electrotechnical problems were solved. One of these problems was the transfer of the electric power to many electronic consumers kept at a high electric potential. Several practical methods for solving this problem are described. These variants were analyzed and tested while designing the cooler construction. The final decision is based on the principle of operation of the cascade transformer containing 33 sections connected in series. The described design solutions can be used not only for future electron coolers in projects NICA-JINR (Dubna, Russia), FAIR (Germany), and MEIC (United States), but also for other high-voltage facilities requiring power transfer to devices held at a high potential. After decommissioning of the electron cooler at Fermilab (United States), the described facility has become the highest-voltage electron cooler worldwide.

Power Quality Experimental Analysis on Rural Home Grid-Connected PV Systems

Microgeneration is the small-scale generation of heat or electric power or both, by individuals or buildings to meet their own needs. Recently, microgeneration is being regarded as a means to decentralize the power production of renewable energies, reducing the impacts on the grid caused by unexpected energy demands. Given the increase in microgeneration facilities, determining the quantity of energy produced and the power quality assumes growing importance in low, medium, or high voltage facilities. This paper presents a power quality analysis of two different facilities with photovoltaic generation localized in a rural area of Portugal, describing the voltage and frequency behaviour, the harmonic contents, and the total harmonic distortion. Statistical data are presented regarding the number of voltage events and occurrence of dips and swells in both facilities as a percentage of rated voltage. We conclude that some PV systems can severely affect voltage quality, forcing the grid to work at and even above the maximum voltage standard limit.

발전소용 4.16 kV급 차단기에서 감전사고 사례 분석

This paper describes electric shock accidents on a 4.16 kV class circuit breaker for power plant. Electric shock accidents mostly involve damage of human life, in comparison with electrical fire, rate of human death tend to be higher in electric shock accidents. Specially, in a high voltage facilities rate of human death comprised about 43.7% by electric shock accidents. If electric shock accidents happen in a 4.16 kV class circuit breaker for power plant, then the power plant discontinue power production. Electric shock accidents in a power plant have a great ripple effect such as an electric power shortage. In this paper, we analyzed electric shock accidents on a 4.16 kV class circuit breaker for power plant. From the analysis results, we confirmed a cause of electric shock accidents on a 4.16 kV class circuit breaker, it happened by defect of interlock equipment or occurrence of breakdown between first feeder contactor and shielding plate. In order to reduce electric shock accidents on a 4.16 kV class circuit breaker, the power plant should consider improvement of interlock equipment and insulation of feeder contactor in circuit breaker.

Health problems from radiation of high-voltage facilities

Aims: The aim of this study was to survey the health problems caused by exposure to high-voltage facility radiation. Materials and Methods: Sampling included workers exposed to electromagnetic fields at high-voltage facilities. The strength of the electric and magnetic fields was determined by a field meter. A questionnaire was used to evaluate the prevalence of subjective and psychological symptoms. Statistical descriptive used and data analyzed by a Student's t-tests. Results: This study indicates that increased symptoms among the exposed workers including depression, anxiety, hostility, paranoia, inter-sensitivity, and obsession-compulsion. Some of the self-reported symptoms were, headache (53.5%), fatigue (35.6%), difficulties in concentration (32.5%), vertigo/dizziness (30.4%), attention disorders (28.8%), nervousness (28.1%), and palpitations (14.7%). A significant relationship was observed between the exposure to the electromagnetic field and psychological symptoms (P < 0.05). Conclusion: Radiation of high-voltage facilities probably increased the risk of mental disorders and intensified them in susceptible workers, especially depression. This finding confirmed the results obtained in provocative studies that indicated an increase in the risk of psychological symptoms, which was put forth by several investigators Observation of occupational health and other control measures play an important role in decreasing the symptoms.