Bus Bar Research Articles

Reduced-scale experimental study of the temperature field and smoke development of the bus bar corridor fire in the underground hydraulic machinery plant

While fire once occurs in a long tunnel, both heat and toxic smoke will be continuously released and become the fatal factors threatening the indoor occupants. This paper mainly studied the characteristics of smoke in the reduced-scale (1:12) corridor model under the natural filling condition. The temperature distribution of the fire-induced smoke and the smoke layer height are tested. The test data are used to access the temperature field for different heat release rates (HRRs) without ventilation in the corridor. The maximum smoke temperatures under the ceiling are all lower than 200°C for HRR less than 1500kW. The smoke temperature stratifies vertically. The stratification can be described by the exponential fit. Besides the temperature field, the smoke layer height is also recorded. Smoke sinks quickly after the ignition. 60 percent of the space has been filled of smoke by the dimensionless time of 300. Then the smoke slows down gradually. In order to achieve more results with different working conditions, full-scale numerical simulation is conducted. There is a good agreement between the reduced-scale experimental and predicted results for the temperature and the smoke layer height, respectively. These provide the basic data of fire scenario in the bus bar corridor. It also affords to predict the smoke development in other underground corridors.

24kV급 배전반의 외함재질과 두께에 따른 Bus bar와 외함의 전자기 손실특성 분석

This paper deals with the electromagnetic loss characteristics of enclosures for a 24kV high voltage switchgear by using a finite element method (FEM). A study on the electromagnetic characteristics of enclosures for a high voltage switchgear should be conducted to minimize the size and the temperature rising of a switchgear. Generally, the enclosures made by stainless steel are used to minimize the eddy current loss caused by the transporting current in Bus bars due to its non-magnetic characteristics although the price of stainless steel is expensive compared with other metal for enclosures. Therefore, a switchgear made by stainless steel enclosures could be fabricated as a small size and are applied to a switchgear in urban substations. On the contrary, the switchgear enclosures made by steel could be fabricated with relatively cheap manufacturing price. However, the temperature easily rises due to the transporting current in Bus bars because steel is a ferromagnetic material. Therefore, the size of a switchgear made by steel enclosures is relatively massive and installed in rural substations. In this paper, the electromagnetic losses in the enclosures of a switchgear according to various enclosure thicknesses are calculated and compared with each other. Especially, we proposed a hybrid type enclosures for a switchgear made by stainless steel (top and bottom enclosure) and steel (left and right enclosure). It is concluded that the cost electromagnetic performance of applying the hybrid type enclosure is favorable to develop a high voltage switchgear.

Rogowski Coil for Current and On-Temperature Monitoring Overhead Transmission Lines

This letter describes the development of a rogowski coil current and on-chip temperature sensor for evaluating the sag of conductors in high voltage transmission line. A rogowski coil has a air core instead of an iron core. The measurement show excellent linearity with practical no saturation problems. In addition, the rogowski rate highly for electrical isolation from the bus bar, and is light weight with low material cost. The uses reliably proven universal serial bus technology to energize the electronic circuitry. The data collected together with sag information will provide support for the development of an algorithm for estimation conductor sag values.

SSPC Active Control Strategy by Optimal Trajectory of the Current for Onboard System Applications

There is a clear trend to increase the use of electrical systems in aircrafts, leading to a growing demand for electrical power in the aircraft. This increasing power consumption has resulted in increasing dc voltage levels, to reduce energy losses and the size of wiring, as a result of the reduced current levels. However, traditional protections such as circuit breakers are not adequate for the protection of the new systems in high dc voltage, and consequently, it is necessary to introduce new technologies in the field of protection devices. One of these is the solid-state power controller (SSPC), which combines the functions of connecting loads to the bus bars and protecting electrical installations against overload and short circuits. On the other hand, within these electrical systems, the connection of certain loads, such as highly capacitive ones (dc-dc, inverters, etc.), implies the need to develop new control strategies to improve the connection process by SSPCs. This paper presents and analyzes a new advanced control strategy that optimizes the performance during the connection of highly capacitive loads using SSPCs.

The Stability of the Second-Order Model of the Damping Single Maching Infinite Bus Bar System

This paper studies the stability of the second-order model of the damping single machine infinite bus bar system,by constructing a suitable Lyapunov function method,and discuss the stability of the equilibrium point,then obtains the attractive area.

Air-Cooled Full-SiC High Power Density Inverter Unit

A 70 kVA/L air-cooled full-SiC three-phase inverter unit including power semiconductor modules, power capacitors, bus bars, gate drive circuits, a PWM wave generator and blower fans has been fabricated as a prototype for EV-use. SiC JFETs and SBDs of 1200 V were used. It has generated three-phase alternative power of 25 kVA to drive a 15 kW-class induction motor with only 190 W of dissipation. The module's temperature was at most 90 ºC.

Transient Temperature and Heat Flux Measurement in Ultrasonic Joining of Battery Tabs Using Thin-Film Microsensors

Process physics understanding, real time monitoring, and control of various manufacturing processes, such as battery manufacturing, are crucial for product quality assurance. While ultrasonic welding has been used for joining batteries in electric vehicles (EVs), the welding physics, and process attributes, such as the heat generation and heat flow during the joining process, is still not well understood leading to time-consuming trial-and-error based process optimization. This study is to investigate thermal phenomena (i.e., transient temperature and heat flux) by using micro thin-film thermocouples (TFTC) and thin-film thermopile (TFTP) arrays (referred to as microsensors in this paper) at the very vicinity of the ultrasonic welding spot during joining of three-layered battery tabs and Cu buss bars (i.e., battery interconnect) as in General Motors's (GM) Chevy Volt. Microsensors were first fabricated on the buss bars. A series of experiments were then conducted to investigate the dynamic heat generation during the welding process. Experimental results showed that TFTCs enabled the sensing of transient temperatures with much higher spatial and temporal resolutions than conventional thermocouples. It was further found that the TFTPs were more sensitive to the transient heat generation process during welding than TFTCs. More significantly, the heat flux change rate was found to be able to provide better insight for the process. It provided evidence indicating that the ultrasonic welding process involves three distinct stages, i.e., friction heating, plastic work, and diffusion bonding stages. The heat flux change rate thus has significant potential to identify the in-situ welding quality, in the context of welding process monitoring, and control of ultrasonic welding process. The weld samples were examined using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) to study the material interactions at the bonding interface as a function of weld time and have successfully validated the proposed three-stage welding theory.

Research on Function Real-Time of Substation Automation System Based on IEC61850

The function real-time of substation automation system based on IEC61850 depends on the distribution mode of logical nodes, the processing speed of logical nodes and the communication delay between logical nodes.The realization principles of functions free distribution are introduced based on IEC61850, take bus protection function and distributed interlock function examples, the functions are deposed into the connection diagram of logical nodes and their communication events are introduced in great detail. The simulation models of D2 substation which has unified network or two-tier network are established with OPNET. The communication events of bus bar protection function and distributed interlock function are simulated and analyzed based on this mode. The rationality of distribution mode of systems functions is quantitative analyzed which provide guidance to improve the real-time performance of systems functions and network structure.

3상 3선식 Plug-In MCCB의 인장력 및 접촉저항 평가에 관한 연구

The purpose of this paper is to evaluate the performance of a Plug-In MCCB developed for rapid power supply restoration when the MCCB is installed in a power system and to verify its reliability. Since the developed 3 <TEX>${\Phi}$</TEX> 3 W Plug-In MCCB can be installed on and removed from a bus bar by one touch using a plug housed at the rear, it can be replaced in a short period of time. Therefore, it can quickly respond to the normalization of a power system. When the Plug-In MCCBB is installed on a bus bar, the resistance between each phase and plug was measured to be 0.46 <TEX>$m{\Omega}$</TEX> in average. When the Plug-In MCCB is installed, the tension in the vertical direction was measured to be 112.78 N in average, which is greater than the tension of 50 N specified in the related regulation. The withstanding voltage tests performed 5 times repeatedly by applying 6 kV to the developed Plug-In MCCB for 60 seconds shows good withstanding voltage characteristics. In addition, both the general waterproof test using a water injection method and the insulation resistance analysis using a Mega meter showed good waterproof and insulation characteristics.

전기자동차 LDC 시스템의 전도 방출에 관한 고주파 모델링 연구

본 논문에서는 고주파 회로 모델링을 이용하여 전기자동차의 LDC로부터 방출되는 전도성 전자파 잡음을 시스템-레벨에서 분석하였다. 관련 전도 방출의 주요 원인은 LDC에서 사용하는 펄스폭 변조 방식의 100 kHz 스위칭 동작에 기인하며, 이러한 전도 방출은 공통-임피던스 결합 및 유도성 결합을 통해 AM/FM 주파수 대역에서의 무선주파수 간섭을 유발한다. 이러한 문제를 분석하기 위해 LDC를 구성하고 있는 MOSFET과 고압 커패시터, 고전압 케이블과 버스 바에 대한 기본 회로는 물론, 각 부분에서 존재하는 기생 성분 및 비선형 특성을 해석하여 LDC 전체를 포함한 시스템-레벨의 고주파 등가회로 모델을 제안하였다. 이러한 모델을 이용하여 시뮬레이션과 측정을 비교하여 유사성을 검증하였다. 향후 이러한 접근 방법이 전기자동차의 전자파 적합성 설계에 효과적으로 사용될 수 있을 것으로 기대한다. In this paper, conducted emission from the LDC(Low-Side DC/DC Converter) of a HEV/EV was analyzed using high-frequency circuit modeling in system-level approach. The conducted emission by PWM process(100 kHz; Switching Frequency) can cause RFI(Radio-Frequency Interference) problems in the AM/FM frequency range. In order to mitigate this conducted emission, a high-frequency equivalent circuit model is proposed by analyzing the fundamental circuits, parasitic components in their parts and connections and non-linear characteristics of MOSFETs, high-power capacitors, inverters, motors, high-power cables, and bus bars which are composed of the LDC. Using these circuit models, results of both simulation and measurement were compared and similarities between them were verified. We are looking forward that this approach can be effectively used in the EMC design of HEV/EV.

Double-Arc Interpolation and Simulation of Free Curve Based on Keller

The free curve as bus bar has increasing number of application in the field of modern machining .While the Keller was not perfect which was found in more and more production practice, in particular doesnt draw and machining of freeform curves. In this paper apply stretching step method to get key nodes, then make use of the double-arc method to approach the free curve, using Visual Basic to preparation of the supporting software, to generate DXF file that can be recognized by Keller, and then achieve the purpose that increasing the ability of free surface processing.

INCOMING AND OUTGOING CT READINGS BASED AI TECHNIQUES FOR BUS BAR DIFFERENTIAL PROTECTION FAULTS ANALYSIS

The application of artificial intelligent approaches was introduced recently in protection of distribution networks. In this paper, the application of Adaptive Neuron Fuzzy Inference System (ANFIS) as well as artificial Neural Network (ANN) for protection of bus bars will be illustrated. The objective of this paper is firstly, to detect the fault occurrence on bus bar, secondly location of the fault. The fault detection and location are firstly trained using ANN and ANFIS techniques and then they are tested in diversity of system conditions with respect to the fault types, inception instant, resistance and pre fault conditions. The fault detection and location units used current magnitude difference change at fault and Pre-fault conditions for incoming and outgoing CTs. The fault location unit in this paper is to detect if the fault occurs internally on the bus bar or externally. The protection system selection depends on the time as the system should take the correct action at fault condition, sending correct tripping signal for internal fault conditions and prevent the mal-operation due to external fault conditions. On other hand, the fault clearing time is very important issue to avoid more damage to power system equipments. From the simulation, it is found that the proposed system success to detect the fault and clarify the fault location at different fault cases within a short detection time than obtained in the previous work.

An Artificial Neural Network Recognition Method for Single-Phase Earth Fault of Ultra-High Voltage Power Grid

Fault diagnosis is very important to make the system return to normal operation quickly after an accident. This paper diagnoses the specific component failure and failure area when the real-time motion information of inputting protection and switch transferred to a trained artificial neural network model by building an artificial neural network diagnosis model of components such as transmission line, bus bar and transformer, training the artificial neural network through taking the failure rule which is found by the historic fault data as a training sample. This method has obvious advantages in the accuracy and speed of diagnosis compared with the previous artificial neural network and overcomes the shortcomings of the incompletion of training samples and not well dealing with the heuristic knowledge.

Preparation of Copper Electrical Engineering Alloy Strip with High Service Properties

Output is organized for industrial batches of electrical engineering strip with improved service properties, i.e., copper bus bars of rectangular section (σ u determination is simplified and surface quality evaluation after bend testing is improved), commutator copper-cadmium strip of trapezoidal section (hardness increased, strip camber reduced, bulges and scratches absent from basic profile), and commutator coppersilver strip (electrical conductivity increased and stable mechanical properties achieved).

Performance assessment and optimization of the ITER toroidal field coil joints

The ITER toroidal field (TF) system features eighteen coils that will provide the magnetic field necessary to confine the plasma. Each winding pack is composed of seven double pancakes (DP) connected through praying hands joints. Shaking hands joints are used to interface the terminals of the conductor with the feeder and inter-coil U-shaped bus bars. The feasibility of operating plasma scenarios depends on the ability of the magnets to retain sufficient temperature and current margins. In this respect, the joints represent a possible critical region due to the combination of steady state Joule heating in the resistance of the joint and coupling losses and currents in ramped operation. The temperature and current margins of both DP and terminal joints are analysed during the 15 and 17 MA plasma scenarios. The effect on the joint performance of feasible optimization solutions, such as rotation of the terminal joints and sole RRR increase, is explored. The characterization of the TF coil joints is completed by the estimation of the coupling loss time constant for different inter-strand and strand-to-joint resistance values. The study is carried out with the code JackPot-ACDC, allowing the analysis of lap-type joints with a strand-level detail.

Consideration and research of high voltage insulation strategy for ITER Feeder busbar joint

The ITER Feeder busbar joint is an important component which connects different sections of busbar which run from the high temperature superconducting current leads to the magnet terminals. High voltage insulated bus bar sections will be assembled onto the feeder support structure (called the containment duct), and the joints between sections will be made in situ. The high voltage insulation over the joint is the final step to complete the insulation of the whole bus bar system, and its quality is key to achieving the required electrical performance of the system. The final joint has a complex external configuration with an irregular structure in places, which makes it difficult for the application of the insulation. The limited access in the Feeder and the complex joint external structure make the implementation of the joint insulation hard to solve. The Feeder group at ASIPP has carried out significant R&D for the joint insulation, involving research on the selection of materials, the design of the insulation structure, the curing technology and the quality inspection method. After many rounds of manufacturing and testing, the insulation strategy for the Feeder joint will focus on the so-called “wet-winding” technology. Despite the fact that this process has some intrinsic disadvantages, it is more appropriate for the joint structure compared to other methods. The sub-suppliers to ASIPP have chosen this impregnation method for the feeder qualification activities based on guidance from ASIPP. This paper describes the research procedure of the ITER Feeder busbar joint insulation, summarizes the activities on the joint insulation structure design, describes the trials of the impregnation method, and describes the pre-qualification tests. Even for the preferable “wet-winding” process, some improvements have been applied due to recommendations from ITER IO experts. For example, both the use of a vacuum bag during the process and investigation using non-destructive tests (NDT) have been implemented.

Testing Results for the Cable Core of a 360 m/10 kA HTS DC Power Cable Used in the Electrolytic Aluminum Industry

IEE has installed a 360-m-long high-temperature superconducting (HTS) dc power cable at the self-supply power plant of Zhongfu Industrial Co., Ltd. in Gongyi, Henan. The cable connects a 19.5 MVA/1.5 kA silicon-controlled rectifier, which connects with a 110 kV/1 kV transformer, to the bus bar of an electrolytic aluminum cell. It is designed to carry 10 kA current and the voltage is 1300 V. The HTS dc power cable core consists of five conductor layers wound with the spliced Bi-2223 wires with the length of 40 km. The cable core has five layers and 23 HTS wires in each layer with the outer diameter of 45 mm. As the items in this project, testing of 4 to 5 m length prototype cables, including a 5 m prototype cable fabricated before the 360 m power cable and a 4 m prototype cable intercepted from the 360 m HTS power cable, is conducted. These prototypes are used to assess the design program, fabrication process, and performance of the 360 m/10 kA HTS power cable including steady state operation at the 10 kA design current and overcurrent fault capability. The critical current of the 5 and 4 m HTS power cable reach 14.3 kA and 13.8 kA at 77 K, 1 μV/cm, respectively. In this paper, the design parameters and fabrication of the 360 m/10 kA HTS dc power cable conducted by IEE are presented. The cable system, installation process and the summary of the results from the testing of 4 and 5 m prototype cables are described. In addition, details of the initial cool-down process and energizing are presented.

Numerical modelling and experimental validation of a low concentrating photovoltaic system

Concentrator solar cells need to be designed optimally depending on the concentrating photovoltaic (CPV) system, application and operating conditions to ensure the best system performance. The important factors while designing include concentration ratio, cell material properties, expected operating temperature, cell shape, bus bar configuration, number of fingers their size and spacing. The irradiation incident on the solar cell while being concentrated experiences several losses caused by the different physical phenomena’s occurring in the system. A particular issue for CPV technology is the non-uniformity of the incident flux on the solar cell which tends to cause hot spots, current mismatch and reduce the overall efficiency of the system. Understanding of this effect and designing the cell while considering these issues, would help in improving the overall performance of the system. This study focuses on modelling a low concentrating photovoltaic system used for building integration, optimising the cell metallisation and analysing the effects of temperature on the overall output of the system. The optical analysis of the concentrator is carried out using ray tracing and finite element methods to determine electrical and thermal performance under operating conditions. Furthermore, an analysis is made to understand the effects of non-uniformity on the output of the device. About 0.5% absolute drop in solar cell efficiency was observed due to non-uniformity at 5o incident angle. A relative drop of 1.85% was observed in the fill factor due to non-uniformity of the flux distribution. A maximum cell temperature of 349.5K was observed across the cell in both uniform and non-uniform conditions under an incident solar radiation of 1000W/m2 which further reduced the performance of the solar cell. The solar cell design was also analysed by varying the number of fingers and the optimum grid design reported. A small prototype concentrator based on the design proposed was made using polyurethane and tested experimentally with the optimized solar cell design. On comparing the results obtained using the experimental data a good agreement in the system output could be seen. The difference in the overall system output was seen to be of the order of 11% which could be due to several losses occurring in the prototype which were not accounted in the model.

Status of series production and test of the HTS current leads for Wendelstein 7-X

The Karlsruhe Institute of Technology (KIT) is responsible for design, production and test of the High Temperature Superconductor (HTS) current leads for the stellarator Wendelstein 7-X (W7-X). In total 14 current leads with a maximum current of 18.2kA are required. Special feature is the upside-down orientation of the current leads because of the location of the power supplies in the basement of the experimental area of W7-X. One further important requirement is the Paschen tight electrical insulation of current leads and the connection to the bus bar system. Due to some very specific manufacturing steps, budget and time restrictions, it has been mutually decided between the project partners to manufacture most of the components in house, except the HTS stacks which have been produced and delivered by industry. As the semi-finished parts were manufactured in the central workshop of KIT, the assembly of the current leads was performed in the ITEP (Institute for Technical Physics). The final acceptance test of the current leads is performed at KIT, using a dedicated test cryostat assembled beside and connected to the main vacuum vessel of the TOSKA facility. The paper describes the status of the manufacturing of the current leads. In addition attention is given to specific problems that occurred during the manufacturing and testing.

Effect of Cooling the Cathode Tab Bus Bar on the Thermal Characteristics of Lithium-Ion Prismatic Cells under Various Discharge Rates of Constant Current

not Available.