Electrical Cabinet Research Articles

Evaluating the applicability of seismic retrofit of an electric cabinet in a power plant

The aim of this study was to find a way to improve earthquake resistance performance more effectively through various reinforcement methods between a cabinet bottom and concrete slab, which is a vulnerable connection in the event of earthquake. In order to improve the earthquake resistance performance of an electric cabinet, methods such as installing a vibration isolation device, increasing the number of connecting bolts between the cabinet bottom panel and base channel, welding a steel grid to the cabinet bottom panel, and so on, were considered and, in order to compare the performance in each case, a three-axis shaking table test was performed. As a result of comparing the seismic performance of each case according to the acceleration response, it was found that the reduction of seismic force was best when applying the vibration isolation device. However, there is a disadvantage in that the spatial and temporal limitations are large and the unit price is high for application in the field. For this reason, it is predicted that the method of ensuring the higher rigidity of an electric cabinet by increasing the number of connecting bolts, as proved through this study, would be a more economical and realistic seismic performance method in field applications.

Effect of the Condition of In-cabinet Equipment in Single door Electrical Cabinet on Seismic Performance

Effect of the Condition of In-cabinet Equipment in Single door Electrical Cabinet on Seismic Performance

State recognition system based on convolutional neural network

Identifying the operating status of the switchgear of the electrical cabinet is of great significance to the safety of the substation. Currently, nonintelligent inspections are used, usually manual inspections, to monitor the switch status, which wastes manpower. More serious is that the shortcomings of non-intelligent inspections are false and missed detections, which can seriously damage the power system. Therefore, to reduce manpower and improve detection accuracy, an intelligent switch detection method based on image recognition is proposed in this paper. Firstly, the identification system of the protection board switch is explained. Secondly, the convolutional neural network model is designed, and a data set is made to train the network model parameters. Finally, the switch pictures in the substation are selected as the data set, and the pictures are identified in the experimental part. The experimental results prove that the method can accurately locate the switch area and switch recognition, which proves the feasibility of the proposed method.

Innovative Technology for Production of Electrical Cabinets Using Laminated Conductors

Electrical cabinets are assembled manually to a great extent. The existing wiring technology of electrical cabinets is a big consumer of plastic materials used for the wire ducts which make up a large portion of the cabinet volume. Also, the current electrical cabinet production requires a lot of human labor. This paper proposes a new laminated conductor technology used for connecting electrical cabinet components. The approach is based on alternately stacking conductive and insulating layers. The primary advantage of the new technology is the possibility of accomplishing a fully automated production by using laminated conductors of rectangular cross sections for interconnecting the components. Additional benefits are reduced size; and a simplified use and installation. Both thermal and mechanical simulation analyses were carried out in the study. The final product of this technological development and its application is a prototype, which was evaluated experimentally for its electrical and mechanical functionality. Thermal conditions were also tested. The tests that were performed in this study include also mechanical testing on the bolts in the circuit block and electrical current tests. The experimental results justify the application of the proposed technology.

Asymmetric HMMs for Online Ball-Bearing Health Assessments

The degradation of critical components inside large industrial assets, such as ball-bearings, has a negative impact on production facilities, reducing the availability of assets due to an unexpectedly high failure rate. Machine learning-based monitoring systems can estimate the remaining useful life (RUL) of ball bearings, reducing the downtime by early failure detection. However, traditional approaches for predictive systems require run-to-failure (RTF) data as training data, which in real scenarios can be scarce and expensive to obtain as the expected useful life could be measured in years. Therefore, to overcome the need of RTF, we propose a new methodology based on online novelty detection and asymmetrical hidden Markov models (As-HMMs) to work out the health assessment. This new methodology does not require previous RTF data and can adapt to natural degradation of mechanical components over time in data-stream and online environments. As the system is designed to work online within the electrical cabinet of machines, it has to be deployed using embedded electronics. Therefore, a performance analysis of As-HMM is presented to detect the strengths and critical points of the algorithm. To validate our approach, we use real life ball-bearing data sets and compare our methodology with other methodologies where no RTF data are needed and check the advantages in RUL prediction and health monitoring. As a result, we showcase a complete end-to-end solution from the sensor to actionable insights regarding RUL estimation toward maintenance application in real industrial environments.

Drying Kinetic of Oven and Cabinet Dried Red Date Fruit

This study was carried out to evaluate the effect of pre-treatment technique (blanching) and temperature on the drying characteristics of the red date variety. Thin layer drying experiments were conducted at varying drying temperatures of 50, 60 and 70 °C using electrical laboratory oven and cabinet dryer with a constant air velocity of 1.4 m/s. Other sets of samples were blanched at 50 °C for 2-, 5- and 10-minutes before being dried at varying drying temperatures of 50, 60 and 70 °C respectively under the same drying conditions. The drying process took place mainly in the falling rate period indicating that the mechanism that governed moisture movement in the samples was diffusion. The drying curve showed that blanched red date fruits had higher drying rate than the un-blanched samples. The result is useful for farmers, researchers, and the processing industry in designing a reliable machine for processing red date fruit which will boost the small and medium scale production of the fruit in Nigeria.

A study on the load characteristics of the anchorage according to the natural frequency change of the electric cabinet in a power plant

Due to the recent earthquakes in Korea, many cases of damage to anchorage of the electric cabinet in the power plant have been reported. Accordingly, for the purpose of reviewing the seismic safety, a study on the load characteristics transmitted to the anchorage during an earthquake is proceeding. It was investigated that the load transmitted to the anchorage also changes according to the change in the natural frequency of the cabinet. However, in the case of cabinets used in the actual field, it is necessary to prove the results of previous studies under more diverse conditions because they are composed of various stiffness. In this study, a structure replacing a cabinet was manufactured and the load transmitted to the anchorage under various conditions was analyzed through an experimental and analytical approach. As a result of this study, it was confirmed that the load transmitted to the anchorage increases as the natural frequency of the structure increases, and a correlation equation between the natural frequency of the structure and the transmission load of the anchorage was derived. Using the correlation equation proposed in this study is expected to help identify the load delivered to the cabinet anchorage under an earthquake.

Numerical and experimental investigation on heat transfer of multi-heat sources mounted on a fined radiator within embedded heat pipes in an electronic cabinet

In this paper, a finned heat sink for thermal management inside electrical cabinets was proposed to address the heat dissipation problem of some electronic equipment which are high heat flux and compact structure. The cooling system is mainly composed of four identical radiators, eight water-charged wickless L-shape heat pipes are embedded at the bottom of each radiator, and hollow fins are used in the condensation section of the heat pipes to enhance heat transfer. A thermal resistance network model of the heat pipe electric cabinet based on the superposition method was conceived. At the first part, experiments are conducted to measure the temperature of the heat source and the air in the air-flow passage. Transient and steady-state studies were carried out under different heating powers at the ambient temperature of 30 °C–35 °C. The maximum temperature difference between each heat source under forced convection is only 3.2 °C, which is more uniform than 10.36 °C in natural convection. The second part proposed a three-dimensional numerical model to further evaluate the heat transfer performance of the heat sink. The distribution characteristics of temperature field and flow field inside the cabinet are obtained by numerical calculation, and the variation of Ra number with height is further calculated. Taking the continuous junction temperature lower than 85 °C as the condition that the components in the cabinet can operate safely, the limit heat dissipation of the cooling device through natural convection can reach 763 W.

Estimating Seismic Demands of a Single-Door Electrical Cabinet System Based on the Performance Limit-State of Concrete Shear Wall Structures

The electrical cabinet systems in power plants are critical non-structural components to maintaining sustainable operation and preventing unexpected accidents during extreme events. This system consists of various electrical equipment such as relays, circuit breakers, and switches enclosed by a steel cabinet for the protection of the equipment. The cabinet systems are installed in and protected by structures so that the cabinet’s behavior is totally dependent on the behavior of the structures when subjected to an earthquake. Therefore, it is essential to qualify the seismic performance of the cabinet system considering the effect of the primary structure where the electrical cabinet system is mounted. In addition, with the implementation of ASCE-43 design standards for nuclear facilities, facility design allowing nonlinear behavior has gained greater attention in nuclear power plants, and research on how the response of the cabinet varies according to allowable damage levels of structures is needed. In this study, Finite Element (FE) models of a single-door electrical cabinet and concrete shear wall structure validated through experimental data are used for a decoupled analysis to estimate the seismic demands of the electrical cabinet. Three different earthquake loadings, referred to as EQ#13, #17, and #19, used in the SMART-2013 project are selected to obtain floor responses of the concrete structure, and the loadings lead to different levels of damage (minor, moderate, and major damage, respectively) to the structure. Finally, the floor responses based on levels of the damage to the primary structure are applied to the electrical cabinet system as input loadings for the decoupled analysis. Thus, this study presents the effects of the cabinet elevation and performance limit-state for concrete shear wall structures on the response of the electrical cabinet, and it shows that while the difference in seismic demands is not significant in the minor and moderate damage states, a meaningful difference occurs in the degree of the major damage state.

Evaluation of Structural and Functional Behavior of Battery Charger for Low/High-Frequency Motions in NPP

Earthquake damage to electrical systems degrades their performances and disrupts their normal functioning. Furthermore, it disrupts nuclear power plant (NPP) operations. NPPs in South Korea have been designed based on the Regulatory Guide 1.60 (RG 1.60) design spectra; however, the Gyeongju earthquakes in South Korea were of high frequency, with magnitudes of 5.1 and 5.8. Therefore, the seismic performances of electrical systems (high-frequency sensitive) must be evaluated to consider low- and high-frequency motions. In this study, to ensure the operation of NPPs in South Korea, the seismic performance and dynamic characteristics of the battery charger (BC) in the electrical subsystem were evaluated experimentally. Seismic tests of the BC were performed to consider low frequencies, high frequencies and a combination of both. The dynamic characteristics of the inside and outside of the cabinet, depending on the input motions, were evaluated and compared based on the tests. Moreover, the acceptance criteria for relay contact chatter were evaluated using the measured output signal during the seismic tests. From seismic test results, the peak acceleration of CRS at the top location (A6) was 1.31 times larger than that of UHS and 1.51 times than that of RG 1.60 and it increased rapidly with increasing PGA levels. Contact chatter was not observed under a peak acceleration of 3.4 g on the installed relay of the panel; however, the relay chatter for more than 2 ms dropped below the reference voltage 46 times. The major components of the electric cabinet were significantly affected by high-frequency motion.

Experimental Investigations of a Passive Cooling System Based on the Gravity Loop Heat Pipe Principle for an Electrical Cabinet

This paper deals with the experimental research and verification of a passive cooling system operating on the principle of a loop gravity heat pipe designed for cooling electrical cabinets. This type of cooling works automatically by changing the state of the working substance and thus saves energy consumption. Since the designed cooling system ensures heat transfer from the interior cabinet to the outdoor space, where the heat can naturally dissipate to the surroundings, it is dustproof. The heat pipe consists of an innovative evaporator concept designed to minimize liquid and vapour phase interference in the refrigeration circuit. The aim of the research was to experimentally determine the limit performance parameters of the refrigeration system for different volumes of working medium in the evaporator and decrease heat loss in the cabinet interior. The designed device was verified experimentally and by mathematical calculations as well. The greatest benefit of the work is that the cooling device was able to ensure temperature conditions inside the electrical enclosure at a heat load of 2000 W under 60 °C, 1500 W under 55 °C, 1000 W under 50 °C, 750 W under 45 °C and 500 W under 40 °C.

Design of Fully Intelligent Quality Error Prevention System for Tobacco Production Line Based on Configuration Software and PLC Program

Aiming at the problems of wrong brand, mixed batch and wrong transmission of electronic parameter information in the production of cut tobacco of different brands in the tobacco industry, a fully intelligent quality error prevention system based on WinCC configuration software and PLC distributed control program is designed. The information of the production and manufacturing execution system in the general control room and the brand, batch and other information stored in the PLC of the bottom electric control cabinet is compared and verified instead of manual self-inspection. If the information is consistent, production is allowed. Otherwise, the equipment locks itself and sends alarm feedback. The design and application of the system realize the automatic error prevention of process equipment and the implementation accuracy of production control parameters, to ensure that the production process meets the requirements of process technology, effectively avoid major quality accidents, and finally guarantee the product quality.

Extension of Established Modern Physics Simulation for the Training of Robotic Electrical Cabinet Assembly

High-performance physics simulation environments are an excellent option to simulate robot-based assembly processes for training faster-than-real-time and providing the necessary data. However, since established physics engines are rigid multi-body simulators at their core, they cannot simulate the deformation process during the assembly of control cabinet terminals. Thus, appropriate extensions of the simulation are necessary. This paper introduces and evaluates extensions incorporating physical joining models to simulate the snap-fit assembly in electrical cabinets. The presented results showed that the extensions can provide input data of high accuracy for the joining models. In this way, they empower the generation of valid training data for snap-fit assembly from standard rigid body simulations.

Final design of the Fiber-Optic Current Sensor bundle in the ITER buildings

The Fiber-Optic Current Sensor (FOCS) will be used in ITER to measure the total plasma current using Faraday effect. Sensing spun fibers will be placed around the Vacuum Vessel (VV) on a poloidal loop in two different VV sectors. To link the loop fibers with the reading instruments, placed several tens of meters away in electrical cabinets, a fiber bundle link is needed. This fiber bundle would start from the tokamak building port-cell, cross several rooms and end in the ITER diagnostics building. The design of such bundle needs to fulfil the unique requirements of ITER buildings, some of them related to safety, such as non-propagation of smoke and fire, as well as maximum allowable leak rate, between two separate rooms. To this regard, the FOCS fiber bundle is classified as a Safety-Relevant (SR) component. To fulfil these requirements, and at the same time achieve a good design using as many Commercial Off The Shelf (COTS) components as possible, the fiber bundle design entailed a complete qualification procedure, aimed at benchmarking the use of the selected components against the required constraints. This paper presents the final design and qualification of the FOCS fiber bundle, from the applicable requirements to the final technical solution, benchmarked through careful qualification tests. Being the first work addressing qualification of safety-relevant fiber bundles in ITER buildings, this work is also considered to be relevant for current and future diagnostics in ITER using similar components.

Heat Flow Field Analysis on Cooling System of Electrical Control Switch Cabinet

The failure rate of distribution system at all levels can be reduced effectively by exploring the change law of temperature rise of electrical control switch cabinet (ECSC), and optimizing the design concept of the cooling system. These efforts can significantly promote the coordinated development of grids at all levels. However, the existing studies rarely discuss the temperature rise law under external factors or non-rated conditions. The factors affecting temperature rise have not been fully considered, not to mention the correlations between these factors. Likewise, few scholars have tried to optimize the design of the cooling system. Therefore, this paper carries out a heat flow field analysis on the cooling system of ECSC. Firstly, the design idea of ECSC cooling system was explained, and the design steps of ECSC cooling were presented. Secondly, a mathematical model was established for the motion of ECSC thermal fluid, based on the laws of conservation of mass, momentum, and energy. Thirdly, a turbulence model and a porous media model were constructed for ECSC heat flow field analysis, after fully considering multiple factors: the compressibility of the fluid, the construction of a special yet feasible problem, the precision requirement, the computing capacity, and the time limit. Finally, the uniformity of the flow field was measured by parameters like mean speed, coefficient of speed fluctuation, and cloud map of speed, the results of ECSC heat flow field analysis were obtained, and useful suggestions were provided for structural optimization.

Seismic Fragility of Electrical Cabinet at Anchor System based on Concrete Material Uncertainties

Seismic Fragility of Electrical Cabinet at Anchor System based on Concrete Material Uncertainties

Metallurgical analyses on Al-Mg alloy pop rivets used in the electric cabinet

One of the rivets connecting the frame and cover plate was broken unexpected in use. To analyze the fracture mode of this Al-Mg alloy pop rivet and prevent the similar events, scanning electron microscopy observation and chemical composition tests were carried out. Fatigue tests were performed to further find out the cause of failure of the Al-Mg alloy pop rivets. The failed rivets showed obvious fatigue fracture characteristics, whereas no corrosive medium could be tracked. The fatigue limit of Al-Mg alloy pop rivets was about 400 N. The stress concentration generated during riveting process and the maximum external forces beyond fatigue limit of aluminum rivets led to the initiation of plastic deformation zone. The low content of Mn and the possible existence of crevice between rivet core and rivet body may promote the initiation of plastic deformation zone. Under the action of continuous external load, the fatigue crack continued to expand, and finally caused the fracture of pop rivet. The effect of corrosive medium on cracking can be eliminated.

Effect of Boundary Conditions on Seismic Response of Electrical Equipment subjected to High-Frequency Ground Motions

The updated ground motion hazard in Central and Eastern United States contains high frequency motions. Such motions do not cause structural damage. However, safety-related electrical equipment are sensitive to high-frequency accelerations. Seismic qualification of electrical equipment requires an in-cabinet response spectrum (ICRS) which depends on the dynamic response of electrical cabinets and buildings. A linear analysis to generate ICRS can give excessively high spectral accelerations. Cabinet models with geometric nonlinearities such as a gap in the connection with building floor show that high-frequency accelerations may not propagate to the electrical equipment. Unlike linear analysis, results from nonlinear analysis of a building-cabinet model with a gap show a periodic pattern of secondary peaks and valleys at higher frequencies. In this research, the unique observation of secondary peaks is explained through fundamental principles by considering the sliding response of a cabinet representation with gap subjected to harmonic excitation. It is observed that a periodic pattern of peaks and valleys exist due to a significantly large contribution from transient response, due to localized impacts at the gap in cabinet base, and its interaction with the steady-state response.

PERBEDAAN KADAR ANTOSIANIN UBI UNGU SEGAR DAN TEPUNG UBI UNGU VARIETAS LOKAL DAN ANTIN 3 PADA BEBERAPA ALAT PENGERINGAN

Background: Purple sweet potato is one of the local Asian food ingredients known as "people's food". Purple sweet potato is rich in anthocyanins which function as antioxidants and immunonutrients. In addition to being widely used as food or traditional snacks, purple sweet potato can be used as a functional food ingredient rich in anthocyanins. For example, purple sweet potato flour can be used as an essential ingredient for processed foods.Objectives: To analyze differences in anthocyanin levels in fresh purple sweet potato local varieties of Gunung Kawi and Antin 3 and purple sweet potato flour with different drying tools.Methods: This research consist of two research stages. The first phase analyzes differences in anthocyanin content in fresh purple sweet potatoes local varieties of Gunung Kawi and Antin 3 with a RAL research design (Completely Randomized Design) 3 repetitions. Then, the second stage of the research used a one-shot case study with 3 treatment groups: drying with an electric oven, cabinet dryer, and food dehydrator. Anthocyanin levels were tested using the UV-Vis spectrophotometry method. Differences in fresh purple sweet potato anthocyanins were analyzed using an independent t-test. Meanwhile, the different anthocyanin levels of purple sweet potato flour were analyzed using one-way ANOVA.Results: The first stage of the study showed that the anthocyanin content of fresh purple sweet potato Antin 3 was seven times higher than that of Gunung Kawi (53.94±25.6 v.s 7.59±2.4 mg/100 g) with p=0.036. The second stage of the study, showed no statistically significant difference in anthocyanin levels (p = 0.066) in 3 different drying equipment.Conclusion: Antin 3 purple sweet potato variety is purple sweet potato with the highest anthocyanin content. The purple sweet potato flour was dried with 3 different drying tools, resulting in anthocyanin levels that were not significantly different.Keywords: Anthocyanin; Gunung Kawi local purple sweet potato; Antin 3 purple sweet potato; Purple sweet potato flour; Drying equipment

Seismic response of electrical cabinets considering primary-secondary structure interaction with contact nonlinearity of anchors

ABSTRACT Seismic assessment of safety-related equipment in a Nuclear Power Plant (NPP) is more demanding compared to general structures owing to their role in the safe operation and shutdown of the plant. In-cabinet response spectra (ICRS) is thereby generated to qualify the performance of the sensitive devices installed in a cabinet. This study presents the effect of post-installed anchor interaction on the seismic response of an electrical cabinet to drive the ICRS considering primary-secondary interaction (PSSI). Nonlinear hysteretic shear behavior of the anchor connection and its interaction with the floor was considered. An equivalent numerical model was developed to imitate the nonlinear behavior of the anchor bolt. The numerical behavior of anchor was validated using the recent available experimental results. A parametric study for the coupled and uncoupled condition was also considered. The seismic response manifests the nonlinear interaction of anchor bolt that is significant to be considered. The response amplification in a coupled system with anchors nonlinearity is more significant than the floor response spectra (FRS) method and the fixed boundary condition. Moreover, for tuned and nearly tuned primary-secondary systems under the linear and nonlinear connection is also addressed.