Bus Bar Research Articles

Simultaneous fault detection and diagnosis in electric power system using hybrid method

Simultaneous fault is one of the challenging issues. Faults are the major hurdles in power system designing and protection .Simultaneous fault is the combination of faults indicates that that two or more faults which occur at the same time.The main objective of simultaneous fault detection, classification and location is satisfy accelerates line restoration, maintains system, stability, repairs the fault, decreases the restoration time and increases the system reliability.This paper presents an approach for analysis, detection, classification and location for simultaneous faults in bus bar and transmission line. Two port network is adapted for analysis , voltage and current measurement method is adapted in the fault detection, neural network in the fault classification and location for different types of fault and places were to estimation accurately fault location by analyzing the data available after the beginning of disturbance.All programs were written in MATLAB environment. The programs were test on IEEE- 11 bus bar network. The results clarified that the voltage and current measurement method and impedance method is very effective for simultaneous fault detection, classification and location.

Circuit implementation of power converter for high-speed switching operations

Recently, high di/dt and dv/dt switching operations of power converter circuits has been discussed for realizing a high-efficiency power converter circuit. In this case, parasitic inductances of the bus bar between a DC capacitor and power devices may cause issues of overshoot voltage and electromagnetic interference(EMI) noise. Therefore, it is necessary to design the bus bar geometry while considering the minimization and optimization of the parasitic inductance of bus bar. This paper discusses a relationship between bus bar geometry and switching characteristics. In addition, the bus bar analysis is based on the PEEC method, and the bus bar geometry is designed by considering the stray inductance with using an inductance-map method. Moreover, this paper also presents a design procedure of acceptable stray inductance based on a standardization method. It should be noted that the stray inductance is designed not for minimization, but optimization, and it is shown not as an absolute value(H), but as a percentage value(%). Finally, the oscillation waveforms under turn-off operation will be discussed depending on the bus bar geometry.

Allocation of Blame After A Safety Incident

Background A significant body of evidence has accrued concerning how people form perceptions and allocate responsibility (e.g., Karlovac & Darley, 1988; Pennington & Hastie, 1986). Human factors researchers have extended this line of research by examining how people allocate blame in product liability cases involving injury or death. Collec-tively, these studies have investigated how perceptions of blame are assigned in a broad range of contexts and to an array of potentially blameworthy entities, including manu-facturers, retailers, consumers, employers and employees, to name but a few. The present study builds on previous research in this area by systematically varying information pertaining to a realistic, but fictitious, incident in which a worker (depicted as experienced vs. inexperienced) is killed when his hand comes into contact with an energized bus bar while feeding electrical wiring into a ground-based electrical pedestal. We systematically manipulated quality of the warning (an actual warning on a commercial product vs. a re-de-signed alternative) and the fatally injured worker’s on-the-job experience (less than one month vs. 4 years). Previous research has shown that quality of warning interacts with efforts on the part of various potentially blameworthy enti-ties (e.g., manufacturers, distributors, employers)to do their part in disseminating warning materials down the chain to end users (Kalsher, Viale & Williams, 2003). We manipu-lated the worker’s level of experience to determine its im-pact on the relative ratio of blame attributed to the manu-facturer and the fatally injured worker. We predicted the “experienced” worker would receive greater blame than the “inexperienced” worker, independent of warning quality. Results and Discussion Overall, participants apportioned most of the blame to the electrician ( M=58.60, SD = 26.07), who was depicted as having failed in his duty to secure protective covers over the energized bus bars. The manufacturer received the next highest percentage of blame ( M=19.87, SD=24.33), fol-lowed by the decedent ( M=14.60, SD=20.02) and job fore-man ( M=14.00, SD=16.70). Manufacturer blame was entered as the dependent vari-able in a 2 (warning: original, re-designed) by 2 (worker experience: under one month, four years) ANOVA. The model was significant, F(3,182)=4.73, p<0.01, eta-squared = 0.07. The effect of warning quality on blame allocated to the manufacturer was significant, F(1,182)=13.35, p<0.001, eta-squared = 0.07, indicating that manufacturers received significantly less blame ( M=13.86, SD=20.47) for the accident given the (better) re-designed warning than they did in the original (poor) warning condition ( M=26.71, SD=26.58). Neither the effect of worker experience nor the interaction of experience and warning condition were sig-nificant ( ps>0.10). The ANOVA described above was replicated using blame apportioned to the decedent as the dependent variable. The model was not significant ( p>0.10), indicating that neither warning quality nor level of experience influenced the amount of blame apportioned to the fatally injured worker. These findings offer the following insights. Contrary to our predictions, the worker’s level of experience did not influence allocations of blame, including to the manufac-turer. Warning quality, however, did influence how blame was apportioned, in particular to the manufacturer. Conse-quently, these findings add to the growing body of evidence suggesting that safety sells. Specifically, evaluators con-sistently assign less blame to manufacturers when they are perceived as adequately warning about their products’ re-sidual hazards.

New Challenges for Tabbing and Stringing Liquid Fluxes

Liquid fluxes are used with tabbing ribbon to form a solder connection with the metallization paste of solar cell. Flux dissolves the oxides present on the surface of the tabbing ribbon as well as the silver bus bar on the top and bottom of the solar cell. With recent advances in automated tabbing and stringing machines, flux performance has increasingly becoming crucial and demanding. This paper reviews the new challenges that have emerged for liquid PV (photovoltaic) fluxes.Several existing issues and challenges are identified and discussed. The challenges were categorized into three main parts i.e. process, material and reliability. Each section is discussed at length and strategy to overcome the problems is proposed. More emphasis is given on pollution and peel strength related issues and approach to formulate next generation liquid fluxes. The analysis indicates that soldering fluxes with enough activity (under class “L” per IPC standard) and ultra fast wetting time are probably the best suit as next generation fluxes.

Study and identification of short-circuit currents at the Complex Distribution Network SIDER-EL Hadjar (ex ArceloMittal-Algerie)

Because of an upcoming the modernization of the electricity distribution network in the SIDER EL-HADJAR steel complex, a new calculation of the short-circuit current must be taken into account. The objectives pursued in this article, is to determine the precise values of the currents of maximum and minimum fault by each start 225kV, 63kV and 15kV of the distribution network to ensure the reliability of the existing system, on the other hand is to validate the sizing of the 63kV bus bar follows the increase of the load of the transformer station P4 by replacing the 70MVA transformer with a 120MVA transformer and comparing the results to the old computation. The calculation of short-circuit currents is a key step in qualifying the equipment to withstand the thermal and electromagnetic effects. So it was question of appreciating the reliability of numerical computation of the currents of short-circuits which requires modeling and simulations with software NEPLAN V5.

THE USE OF WIND-HYDROGEN UNINTERRUPTED POWER SUPPLY PLANT IN DIFFERENT CLIMATIC CONDITIONS

The paper presents the project of the autonomous power complex on the basis of wind-power plant and hydrogen module with a capacity in 3 kW with further replication to 50 kW and shows the possibilities of operation of the present plant in different climatic conditions of Russia: Siberia, the Far East, the Northern Caucasus, Krasnodar territory, and also for universal use in climatic zones of the Arctic and Antarctic, deserts of Africa and the isolated islands with typical destructive sea salt fogs.This paper carries out the study, comprehensive analysis and comparison of known types and classes of wind plants, as a result of which the authors have developed an innovative multi-tier scalable vertically-axial wind power plant. This unit is used as the main power source, the uninterrupted part of which is based on a cyclically operating hydrogen module, contains an electrolytic cell, a fuel cell system and a hydrogen storage device with a communication and control system. The components of the power plant developed by the authors’ team operate at a single DC voltage and can be connected to a common bus bar with an increase of power in this complex. Flexible control algorithms allow optimizing the operation of the power complex to reduce the start-stop frequency, thereby increasing both the service life and time intervals between maintenance. Remote control provides monitoring and management of electricity output processes and hydrogen storage with the help of Internet technologies in long-term modes.The study has shown that this equipment is long-lived, reliable and environmentally friendly, and the system is modular and flexible because it is easily scaled under consumer’s control including the personal power consumption and small business. Moreover, the developed power plant is accessible in purchase, mounting and operation for remote energy consumers as far as the assessed value of equipment is correlating with the cost of power line installation and the operation of equipment does not require large engineering and technological skills.

A scalable life cycle inventory of an automotive power electronic inverter unit\u2014part I: design and composition

PurposeA scalable life cycle inventory (LCI) model, which provides mass composition and manufacturing data for a power electronic inverter unit intended for controlling electric vehicle propulsion motors, was developed. The purpose is to fill existing data gaps for life cycle assessment (LCA) of electric vehicles. The model comprises new and easy-to-use data with sufficient level of detail to enable proper component scaling and more in-depth analysis of inverter units. It represents a stand-alone three-phase inverter with insulated gate bipolar transistors (IGBTs), typical in electric vehicles. This article (part I) explains the modeling of the inverter design including the principles for scaling, exemplifies results, and evaluates the models’ mass estimations.MethodsData for the design of power electronic inverter units was compiled from material content declarations, textbooks, technology benchmarking literature, experts in industry, and product descriptions. Detailed technical documentation for two electrically and electronically complete inverter units were used as a baseline and were supplemented with data for casings, connectors, and bus bars suitable for automotive applications. Data, theory, and design rules were combined to establish a complete model, which calculates the mass of all subparts from an input of nominal power and DC system voltage. The validity of the mass estimates was evaluated through comparison with data for real automotive inverter units.Results and discussionThe results of the LCI model exemplifies how the composition of the inverter unit varies within the model range of 20–200 kW and 250–700 V, from small passenger car applications up to distribution trucks or city buses. The models’ mass estimations deviate up to 14% from the specified mass for ten examples of real inverter units. Despite the many challenges of creating a generic model of a vehicle powertrain part, including expected variability in design, all results of the model validation fall within the targeted goal for accuracy.ConclusionsThe LCI model combines different principles for the scaling of subparts into one model that capture important design implications of different power demands and voltage ratings. The model can be used for a generic estimation of the mass and material composition of a power electronic inverter unit controlling electric propulsion motors, for LCA, when specific data is lacking.

A Breakthrough in Plating for Solar Cell Metallization

Today’s world PV market is dominated by standard crystalline solar cells (so-called Al-BSF cells) and part of the market is shifting to PERC solar cells. The shift is obtained by introducing three additional process steps to the standard process (rear side cleaning, passivation and laser opening), and allows a gain of typically 1% absolute in efficiency. Next generation c-Si technologies should feature higher voltage solar cells with higher efficiency and less processing steps in the manufacturing, allowing for further cost reduction, both at the PV panel level and for the final cost of solar electricity. AMPERE, H2020 funded project, (http://www.ampere-h2020.eu/) focuses on technologies with such a potential and capitalizes on the high tech investments made in Europe over the last decade for establishing advanced manufacturing processes for crystalline silicon heterojunction (SHJ) solar cells and modules. A main cost factor in such cell processing, as expected, was found to be the silver based metallization. Estimating a silver paste consumption of 200mg, for a bifacial SHJ cell, and a silver paste cost conservatively estimated at 800 USD/kg for low-temperature paste, in a 23% efficiency cell, the silver cost will be around 3.0c$/Wp accounting for almost the 20% of the total industrial cost of the SHJ bifacial cell. Silver should be replaced on a large-scale basis by a more cost-effective material. Copper (Cu) is the intended substitute. The expected introduction of Cu into mass production is delayed mainly due to the big progress in screen printing and also due to some technical issues in reliability, adhesion that have to be resolved as also appropriate equipment and processes need to be available with the appropriate footprint and productivity. Comparing the state art of PV industrial plating a breakthrough plating process for SHJ copper metallization will be presented. Selective processing technique based on dynamic liquid drop/meniscus (DLD/DLM) allows metallization of solar cell fingers and bus bars without using any kind of lithography [1]. Figure 1.A presents the 2D view of how the DLD works. The system is composed, in a principle implementation, by an internal jetting outlet where a liquid flow is forced, and an external recalling inlet where by a depression the liquid is recalled back into the system. The input channel, confined by rigid wall (i.e. solid material), pumps a constant liquid flux that, depending on the input nozzle dimension, fixes the velocity of the liquid exiting the input channel. Due to a lower pressure in the surrounding of output channel, the airflow (gas) sustains the liquid (figure 1.A: black arrows in the red liquid) forming the DLD. The dynamic characteristics is due to the constantly refreshment of the liquid, during time, inside the drop. As the substrate gets in contact with the DLD, a DLM is formed, as shown in figure 1.B. Such technique allows to touch the surface of a solar cell only in specific defined positions and to perform electrochemical plating treatments in a localized manner. In DLM speed of liquid is in the meter per second range, like in a jet-plating technique, allowing to have fast deposition rate of metals. Due to the fast speed of liquid flow, the plating rate of copper is in the range of micron per seconds. In figure 1.C is shown an 100 micron width meniscus formed on glass substrate and the direction of movement of the DLM is indicated by the arrow. The ongoing result of EU Horizon2020 AMPERE project relative to copper metallization on ITO with fingers down to less than 60 micron width will be presented showing how by special reduction technique of ITO plus a thin barrier layer of nickel (figure 1.E and 1.D shows SEM cross-section of ITO reduced with thin layer of plated Ni), is possible without damaging the solar cell life time, obtain very good specific contact resistance (i.e. < 0.3mΩcm2) with 10 micron of copper and good adhesion (i.e. >2N/mm). Moreover, due to the fast plating condition, it will be shown that the equipment footprint can be interestingly reduced down to less than 18sqm for a 100MW line managing very low amounts of chemical. Due to its unique characteristics, DLD/DLM technique thanks to speed of processing, localized processing, small footprint and reduced chemical consumption, will represents a breakthrough in the market of plating for the solar cell applications. [1] M. Balucani, et al.; “New Selective Processing Technique for Solar Cells”, Energy Procedia (2013) 43, 54-65 Figure 1

Deposition and characterization of ITO thin film over glass for defogger application and for solar photovoltaics

Indium thin oxide (ITO) films have been used in solar cell applications as top conducting layers for many years. These films possess very good transmission and a low sheet resistance thus making them ideal candidate material for top conducting layers in thin film and HIT solar cells. In the present work, ITO films have been deposited over soda lime glass substrates for use as defogger applications, and for use as front contact electrode in HIT type solar cells as well. ITO deposition is done using pulsed DC sputtering technique inside a vacuum chamber with large size ITO sputtering target of 15 inches by 5 inches. Silver bus bars are printed at the two edges of glass using thick film screen printing technique and the firing of thick film is done in a belt furnace. The deposited ITO thin film characterization is done by using XRD, SEM and 4 probe sheet resistance measurement techniques. The transmission spectra is analyzed for optical transmission properties.

Mechanical and wear properties of friction stir welded dissimilar AA6101-T6 and AA1350 alloys: Effect of offset distance and number of passes

AA6101-T6 and AA1350 aluminum alloys have wide-spread applications in electrical industries, especially in bus bar conductors. Hence, joining of these two alloys is inevitable. Main invention of friction stir welding is joining lightweight structures. We investigated the impact of number of passes and changes in location of tool from retreating side to advancing side on the welding properties of AA6101-T6 and AA1350 alloys. For analyzing the welding properties, tensile, bending, wear, micro hardness and microstructural tests were carried out. We found that double pass and offset distance in advancing side exhibits better welding properties, whereas single pass and offset distance in retreating side exhibit poor welding properties. From the analysis of variance (ANOVA), we also determined that offset distance is the most influencing welding parameter than the number of passes.

A Fast Bus Bar Protection Based on Fault Superimposed Current Polarity Comparison

In order to avoid problems caused by data synchronization of distributed bus bar protection and current transformer (CT) transient saturation, a novel fast bus bar protection was proposed based on fault superimposed current polarity comparison. The bus protection takes the pre-fault voltage and pre-fault current as the new reference for polarity comparison, and it utilizes the relationship between the pre-fault current and superimposed current to identify the fault direction. For internal faults to bas bur, the polarities of the branches connected to the faulted bus bar are identical, for external faults, the polarities are not exactly same. The time window length of fast bus bar protection is very short, and the relay is also immune to the CT transient saturation. The theoretical analysis and PSCAD/EMTDC simulation tests show that the bus protection operates reliably and rapidly, and that its performance is immune to the influences of various fault types, fault path resistance and fault inception angle.

The algorithm with synchronized voltage inputs for islanding detection of synchronous generators

This paper presents a new algorithm for the islanding detection of synchronous generators. The algorithm uses synchronized phase voltages measured in all three phases on the main grid side and at the bus bars of the generator as input signals. Synchronized voltage measurement was performed using synchronized measurement technology (SMT). The algorithm based on digital phase comparison is the measured voltages and, based on the Islanding Detection Index (IDI), detects the occurrence of islanding operation. The algorithm testing was performed on the model of a radial distribution grid with two synchronous generators. The radial distribution grid is modeled in the MATLAB/Simulink software package. The test results show the good properties of the proposed algorithm.

Investigation on Overvoltage caused by Connecting Shunt Reactors with Vacuum Circuit Breakers in Offshore Wind Farms

Nowadays, the transient overvoltage occurs in offshore wind farms has aroused widespread concern. To improve the existing offshore wind farm model’s accuracy in high frequency conditions, this paper proposes a high frequency model of the vacuum circuit breaker as well as a shunt reactor model considering the influence of stray capacitance. After that, a model of a typical offshore wind farm is constructed for the purpose to analyze the overvoltage occurring at bus bars and wind turbine transformers in the process of connecting a shunt reactor. Simulations show that connecting a shunt reactor in offshore wind farms cause overvoltage of high peak and high steepness compared than with those in onshore wind farms.

Hot‐Pressed Hybrid Electrodes Comprising Silver Nanowires and Conductive Polymers for Mechanically Robust, All‐Doctor‐Bladed Semitransparent Organic Solar Cells

AbstractFuture low‐cost, high‐throughput production of organic solar cells in roll‐to‐roll printing processes calls for all‐solution‐processable device architectures. Mechanical flexibility and robustness are mandatory to roll the solar foils during printing and to eventually comply with certain end‐user requirements. Here, we report on semitransparent organic solar cells, comprising top and bottom silver nanowire (AgNW) electrodes that were embedded into conductive poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). The devices exhibited excellent robustness in bending experiments with radii of 5 and 2.5 mm as well as upon folding. To avoid short circuits from nanowires that could stick out of the bottom electrodes, the PEDOT:PSS:AgNW layers were flattened by hot‐pressing after deposition. All solar cells were fabricated in air by doctor blading and exhibited a clear (haze‐free) transparency due to the absence of bus bars. On photoactive areas of 0.5 cm2, power conversion efficiencies of 3.8 % were obtained.

Implementation and Performance of a Current Sensor for a Laminated Bus Bar

This paper proposes a current sensor embedded in a laminated bus bar. The proposed sensor is based on the Rogowski coil principle; the sensor can detect the magnetic flux corresponding to a derivative waveform of the current in a laminated bus bar. The electrical stray elements of the sensor depend on its geometry. The magnetic flux generated by the bus bar depends on the current repartition which is a function of the equivalent frequency during current transients. Both phenomena are discussed using partial element equivalent circuit-based software. Thanks to these investigations, the sensor is designed to measure switching waveforms. It is confirmed that the verification of the proposed current sensor embedded in a laminated bus bar can perform the measurement of a switching waveform using a buck converter circuit rated at 50 V and 8 A.

Measurement of Switching Waveforms with a Current Sensor for a Laminated Bus Bar

Measurement of Switching Waveforms with a Current Sensor for a Laminated Bus Bar

A Rogowski Digital Integrator With Comb Filter Signal Processing System

In this paper, a new type of Rogowski digital integrator signal processing system has been developed for the dc test platform which located in the Institute of Plasma Physics. This signal processing system is mainly composed of the dual-coil subtraction structure and the digital signal filtering processing method that comb filter combined with high-pass filter (HPF) and low-pass filter (LPF). Trigger noise comes from the converter; it can be coupled to the integrator through distributive capacitance between dc bus bar and Rogowski coil; it will affect the integrator seriously; for example, the amplifier in integrator will be saturation, and the integrator cannot work, burrs lying in integration result. The dual-coil subtraction structure can attenuate the trigger noise significantly from hardware perspective and is convenient for the integrator to take a high gain without saturation. The comb filter combined with HPF and LPF can attenuate the trigger noise further and smooth the integration result. The experiment indicates that the approach proposed in this paper can reduce the impact of trigger noise on the integrator and improve the measurement accuracy.

Seismic Response Analysis of Silo-Stock-Foundation Interaction System

To analyze the response law of silo-stock-foundation interaction system under seismic load, a dynamic equation of this interaction system was established. Furthermore, the dynamic characteristics of the silo-stock- oundation interaction system under different storage conditions were studied through numerical analysis. The displacement at the silo top was much greater than that at the silo bottom, while the vibration trend of the upper and lower silos on the same bus bar was similar. The acceleration response, displacement and stress response of the structure increased with the increase of the input seismic wave. Furthermore, the direction time responses of several typical silo parts were consistent. With increase in storage material, the acceleration peak of the silo and bulk material increased and then decreased. This indicates that the relative motion of the storage material and silo had a damping effect on the silo system. The maximum circumferential strain and equivalent stress of silos with different storage capacities were recorded at the variable section of silos (the top of funnel). The effective stress beneath foundations near silos was obviously higher than that far away from silos. These results can provide a reliable theoretical basis and reference values for mitigating silo structural failures under seismic load.

Embedded Design in Synchronization of Alternator Automation

In this paper, a new method for automatic synchronization of alternator has been developed without the necessity of manual interpretation. Any Alternator can be connected automatically to the infinite bus bar with this developed control unit. The phase voltage, phase angle, phase sequence and frequency of the incoming alternator is compared with the reference infinite bus bar with the help of various sensing modules and interpreted by microcontrollers. If the conditions are observed to be optimistic then automated synchronization is done with a prior indication. The system is entirely automated and works entirely on LabVIEW environment. This synchronization technique is cost-effective, reliable, fast and precise to be used for measurement, control, monitoring and parallel operation of alternator. This research is made to overcome the drawbacks of manual methods of alternator synchronization.

Disconnector switching induced transient voltage and radiated fields in a 1100 kV gas insulated substation

Very fast transient overvoltages (VFTO) generated in a gas insulated substation (GIS) during disconnector switching operations are one of the major concerns in insulation design of the GIS. Such over voltages can cause malfunctioning of the protection and control circuits in addition to initiating faults inside the gas insulated bus ducts especially in the presence of metallic particles. In this paper, VFTOs have been estimated at various locations using EMTP in a 1100kV rated GIS during disconnector switching operations. For the substation studied, the maximum computed overvoltage is 1.76p.u without considering the trapped charge on the bus bar and it reaches 2.54p.u with a trapped charge of −1p.u. Major frequency components in the computed VFTO lie in the range of 800kHz to 15MHz. Studies on mitigation of VFTO by the use of damping resistors in the disconnector showed that a resistance close to 500Ω gives the best results. For the bus sections with trapped charge, increasing the resistance value above 500Ω results in a negative peaking of VFTO. Transient radiated fields through the bushings of the GIS are also studied for electro magnetic compatibility (EMC) design of the substation.