Search Results (30)

Electrical cabinet fire scenarios constitute a significant risk within nuclear facilities, emphasizing the need to mitigate uncertainties in risk evaluations. Owing to the disparate nature of electrical cabinet parameters, only a few factors have been experimentally explored and statistically analyzed to assess their impact on peak HRR. In this study, we conducted both a cabinet parameter study and a combustible configuration study to systematically evaluate their influence on peak HRR and time-to-peak HRR. A series of 51 simulation matrices were created using statistical experiment design (SED) and ANOVA to quantify the influence of cabinet volume, combustible surface area, vent area, ignition characteristics, and burning behavior (e.g., HRRPUA and duration). A computational fluid dynamics (CFD) model, specifically a Fire Dynamics Simulator (FDS), was used to model the ignition source and flame spread inside of the electrical cabinet that influence peak HRR. The most impactful parameters influencing peak HRR and time-to-peak HRR were identified. The findings revealed that the configuration of combustibles and the placement of the ignition source play a pivotal role in determining the peak HRR. A partition screening analysis was conducted to identify the conditions under which the ventilation area becomes a more significant parameter. Additionally, a comparison between experimental results and numerical simulations demonstrated good agreement, further validating the predictive capability of the model. Full article

Given the critical role of electrical cabinets in the post-earthquake recovery and emergency response of nuclear power plants (NPPs), a comprehensive assessment of their seismic performance is essential to ensure operational safety. This study analyzed seismic behavior by fabricating an electrical cabinet model based on the dynamic characteristics and field surveys of equipment installed in a Korean-type NPP. A shaking table test with simultaneous tri-axial excitation was conducted, incrementally increasing the seismic motion until damage was observed. A numerical model was then developed based on the experimental results, followed by a seismic response analysis and comparison of results. The findings verified that assuming fixed anchorage conditions in the numerical model may significantly overestimate seismic performance, as it fails to account for the nonlinear behavior of the anchorage system, as well as the superposition between global and local modes caused by cabinet rocking and impact under strong seismic loading. Furthermore, damage and impact at the anchorage amplified acceleration responses, significantly affecting the high-frequency range and the vertical behavior, leading to substantial amplification of the in-cabinet response spectrum. Full article

With the development of society and the advancement of technology, the application of electricity in modern life has become increasingly widespread. However, the risk of electrical fires has also significantly increased. This paper thoroughly investigates the causes, classifications, and challenges of electrical fires in special environments, and summarizes advanced detection and extinguishing technologies. The study reveals that the causes of electrical fires are complex and diverse, including equipment aging, improper installation, short circuits, and overloading. In special environments such as submarines, surface vessels, and aircraft, the risk of electrical fires is higher due to limited space, dense equipment, and difficult rescue operations. This paper also provides a detailed analysis of various types of electrical fires, including cable fires, electrical cabinet fires, transformer fires, battery fires, data center fires, and residential fires, and discusses their characteristics and prevention and control technologies. In terms of detection technology, this paper summarizes the progress of technologies such as arc detection, video detection, and infrared thermography, and emphasizes the importance of selecting appropriate technologies based on specific environments. Regarding extinguishing technologies, this paper discusses various means of extinguishing, such as foam extinguishing agents, dry powder extinguishing agents, and fine water mist technology, and highlights their advantages, disadvantages, and applicable scenarios. Finally, this paper identifies the limitations in the current field of electrical fire prevention and control, emphasizes the importance of interdisciplinary research and the development of advanced risk assessment models, and outlines future research directions. Full article

The rise of new energy technologies has accelerated progress towards sustainable development, and many companies are beginning to invest in renewable resource-related facilities. Electric bicycles have always been an important mode of green transportation; however, they also have problems such as slow charging, difficult charging, and that burning and short circuiting may occur during charging. Electric bicycle battery exchange cabinets effectively solve these problems by exchanging low batteries with full batteries instead of charging. However, current battery exchange cabinets face the problems of insufficient construction and unreasonable site selection. Therefore, this paper proposes a location selection model for electric bicycle battery exchange cabinets based on point demand theory, aiming to maximize rider satisfaction and the service capacity of exchange cabinets. The immune algorithm is introduced to solve the location model; however, the traditional immune algorithm has some problems such as poor stability and slow convergence. In this paper, the mutation process of the traditional immune algorithm is improved by introducing multi-point mutation, guided mutation, and local search. Finally, based on the data of electric bicycle riders in Shanghai, we verify that the location model based on point demand theory performs well on two objective functions of rider satisfaction and battery exchange cabinet service capability. We also expand the application of point demand theory to location models. Then, by conducting experiments with different parameter groups, through sensitivity analysis and convergence analysis, we verified that the improved immune algorithm performs better than the traditional immune algorithm in its accuracy, search accuracy, stability, and convergence. Full article

Utilizing panel quantile regression on an unbalanced dataset for 30 European countries from 2008 to 2018, this article seeks to investigate how the age of cabinet members influences e-waste recycling rates in European countries, alongside other relevant factors. Prior research has overlooked the age of cabinet members as a determinant of e-waste recycling. By addressing this gap, this study introduces a novel factor that could impact e-waste recycling rates. Thus, this study provides insights into how the demographic characteristics of parliament members, particularly the age of cabinet members, impact environmental improvement, as indicated by e-waste recycling rates. Estimation results indicate the existence of a nonlinear relationship (i.e., an inverted U-shaped environmental Kuznets curve) between the age of cabinet members and the e-waste recycling rate, rather than a linear relationship. The calculated average turning point age is 49.087, indicating that the e-waste recycling rate increases as the age of cabinet members rises until reaching 49.087, after which the e-waste recycling rate declines. Overall, this study underscores the importance of the demographic characteristics of parliament members, particularly the age of cabinet members, in shaping e-waste recycling policies and environmental sustainability efforts. It emphasizes that the age of cabinet members and generational perspectives can influence their awareness, understanding, and commitment to addressing contemporary challenges such as e-waste. Full article

Considering the widespread presence of switching devices on the power grid (including renewable energy system inverters), network distortion is more prominent. To maximize network efficiency, our goal is to minimize these distortions. Measuring the voltage and current total harmonic distortion (THD) using power meters and other specific equipment, and assessing power factor and peak currents, represents a crucial step in creating an efficient and stable smart grid. In this paper, we propose a power meter capable for measuring both standard electrical parameters and power quality parameters such as the voltage and current total harmonic distortion factors. The resulting device is compact and DIN-rail-mountable, occupying only three modules in an electrical cabinet. It integrates both wired and wireless communication interfaces and multiple communication protocols, such as Modbus RTU/TCP and MQTT. A microSD card can be used to store the device configuration parameters and to record the measured values in case of network fault events, the device’s continuous operation being ensured by the integrated backup battery in this situations. The device was calibrated and tested against three industrial power meters: Siemens SENTRON PAC4200, Janitza UMG-96RM, and Phoenix Contact EEM-MA400, obtaining an overall average measurement error of only 1.22%. Full article

To further improve the fuel economy of hybrid tractors, an energy management strategy based on model predictive control (MPC) solved by dynamic programming (DP) is proposed, taking into account the various typical operating conditions of tractors. A coupled dynamics model was constructed for a series diesel–electric hybrid tractor under three typical working conditions: plowing, rotary tillage, and transportation. Using DP to solve for the globally optimal SOC change trajectory under each operating condition of the tractor as the SOC constraint for MPC, we designed an energy management strategy based on DP-MPC. Finally, a hardware-in-the-loop (HIL) test platform was built using components such as Matlab/Simulink, NI-Veristand, PowerCal, HIL test cabinet, and vehicle controller. The designed energy management strategy was then tested using the HIL test platform. The test results show that, compared with the energy management strategy based on power following, the DP-MPC-based energy management strategy reduces fuel consumption by approximately 7.97%, 13.06%, and 11.03%, respectively, under the three operating conditions of plowing, rotary tillage, and transportation. This achieves fuel-saving performances of approximately 91.34%, 94.87%, and 96.69% compared to global dynamic programming. The test results verify the effectiveness of the proposed strategy. This research can provide an important reference for the design of energy management strategies for hybrid tractors. Full article

This study investigates the airflow and thermal management of a compact electric energy storage system by using computational fluid dynamic (CFD) simulation. A porous medium model for predicting the flow resistance performance of the battery modules in a battery cabinet is developed. By studying the influence of rack shapes, the effects of heat exchanger arrangements and other parameters on the airflow and battery thermal distribution are analyzed. When applying a larger bottom air channel, the inlet flow uniformity of each battery cabin in the cabinet increases by 5%. Meanwhile, temperature standard deviation decreases by 0.18 while raising the flow rate from 3 m/s to 8 m/s, indicating better temperature uniformity in the battery cabin. When the charge–discharge ratio reaches 0.5 C, the temperature deviation of the entire cabinet significantly increases, reaching 8 K. Furthermore, a rack-level thermal management scheme is proposed to effectively reduce the thermal deviation of the container electric energy storage system and improve the overall temperature uniformity. Results reveal that the rack-level thermal management of the wavy cabinet in the electric storage container can effectively improve the thermal uniformity of the distributed battery cabin, and the overall thermal deviation is controlled within 1.0 K. Full article

Despite the continuous advancement of intelligent power substations, the terminal block components within equipment cabinet inspection work still often require loads of personnel. The repetitive documentary works not only lack efficiency but are also susceptible to inaccuracies introduced by substation personnel. To resolve the problem of lengthy, time-consuming inspections, a terminal block component detection and identification method is presented in this paper. The identification method is a multi-stage system that incorporates a streamlined version of You Only Look Once version 7 (YOLOv7), a fusion of YOLOv7 and differential binarization (DB), and the utilization of PaddleOCR. Firstly, the YOLOv7 Area-Oriented (YOLOv7-AO) model is developed to precisely locate the complete region of terminal blocks within substation scene images. The compact area extraction model rapidly cuts out the valid proportion of the input image. Furthermore, the DB segmentation head is integrated into the YOLOv7 model to effectively handle the densely arranged, irregularly shaped block components. To detect all the components within a target electrical cabinet of substation equipment, the YOLOv7 model with a differential binarization attention head (YOLOv7-DBAH) is proposed, integrating spatial and channel attention mechanisms. Finally, a general OCR algorithm is applied to the cropped-out instances after image distortion to match and record the component’s identity information. The experimental results show that the YOLOv7-AO model reaches high detection accuracy with good portability, gaining 4.45 times faster running speed. Moreover, the terminal block component detection results show that the YOLOv7-DBAH model achieves the highest evaluation metrics, increasing the F1-score from 0.83 to 0.89 and boosting the precision to over 0.91. The proposed method achieves the goal of terminal block component identification and can be applied in practical situations. Full article

This study utilizes a simplified two-dimensional time-dependent computational fluid dynamic (CFD) model to compare the performance of single- and two-layer air curtains in an open-type multi-deck refrigerated display cabinet. Two layers of air curtain generate a more effective invisible barrier from ambient air impact that can reduce electrical energy consumption and maintain a uniform temperature distribution within the cabinet. The CFD model of a refrigerated display cabinet was validated by the experimental data. The results showed a two-layer air curtain advantage over a single air curtain. Electrical energy consumption decreased by 18.5%, and the average temperature of the test products decreased from 5.75 °C to 5.17 °C. The results obtained are important for cabinet design to improve the quality of product storage and reduce energy consumption. Full article

Since the insulation performance of air is not as good as that of $S{F}_6$ and other gases, it is necessary to conduct an in-depth study on the insulation characteristics of the fuse tube in order to meet the requirements of normal breaking and to design a structural improvement scheme for a 12 kV environmental protection cabinet fuse tube that is suitable for using air as the insulating medium. In this study, the insulation performance of the fuse tube before improvement was studied, and the electric-field distribution of the 12 kV fuse tube placed in the air-insulated switchgear was analyzed. The results showed that the electric-field was heavily concentrated in the air gap of the fuse tube plug and around the ground rod. In this study, the structure of the fuse tube was specifically designed. By spraying conductive paint on the intersection surface of different media, equipotentiality was achieved, and a reasonable metal shielding structure was added to the site where the field intensity was concentrated so as to improve the distribution of the electric-field and avoid the breakdown caused by the concentration of field intensity. Through several improved designs, the maximum electric-field strength of the fuse tube of an environmental protection cabinet can be effectively reduced, and the insulation requirements of relevant standards can be met. A partial discharge test for the improved fuse tube was carried out, and the local discharge quantity of the improved fuse tube met the industry requirements, which verified the rationality of the fuse-tube-improvement scheme. Full article

The article presents in detail the construction of a low-cost, portable online PD monitoring system based on the acoustic emission (AE) technique. A highly sensitive piezoelectric transducer was used as the PD detector, whose frequency response characteristics were optimized to the frequency of AE waves generated by discharges in oil–paper insulation. The popular and inexpensive Teensy 3.2 development board featuring a 32-bit MK20DX256 microcontroller with the ARM Cortex-M4 core was used to count the AE pulses. The advantage of the system is its small dimensions and weight, easy and quick installation on the transformer tank, storage of measurement data on a memory card, battery power supply, and immediate readiness for operation without the need to configure. This system may contribute to promoting the idea of short-term (several days or weeks) PD monitoring, especially in developing countries where, with the dynamically growing demand for electricity, the need for inexpensive transformer diagnostics systems is also increasing. Another area of application is medium-power transformers (up to 100 MVA), where temporary PD monitoring using complex measurement systems requiring additional infrastructure (e.g., control cabinet, cable ducts for power supply, and data transmission) and qualified staff is economically unjustified. Full article

Tilapia farming is the predominant aquaculture activity, with 4623 aquaculture farms in Mexico alone. It is relevant to apply technological alternatives to mitigate production costs, mainly those associated with supporting energy savings for aeration and water pumping in aquaculture farms. There is limited information confirming the feasibility of implementing photovoltaic systems connected to the grid (On grid-PV) in aquaculture farms. The working hypothesis proposed for the development of the work was that On Grid PV systems in Tilapia aquaculture farms in Mexico are technically feasible, economically viable and environmentally acceptable. Therefore, the objective of this research is to design a grid-connected photovoltaic system for rural Tilapia aquaculture farms in Mexico and analyze it with a feasibility assessment through technical, economic and environmental variables, as part of the link between academia and the productive sector. Methodologically, the On Grid-PV design was carried out in an aquaculture farm in Veracruz, Mexico, as a case study. It was developed in two stages: the field phase (1), where a non-participant observation guide and a survey with open questions were applied to perform the energy diagnosis, and the cabinet phase (2) where the calculation of the economic and environmental variables was carried out with the clean energy management software Retscreen expert, the engineering design was based on the Mexican Official Standard for electrical installations, and Sunny Design 5.22.5 was used to calculate and analyze the electrical parameters of the On Grid PV. The results revealed an investment cost of USD 30,062.61, the cost per KWp was of 1.36 USD/Watt, and the economic indicators were the net present value (USD 41,517.44), internal rate of return (38.2%) and cost–benefit ratio (5.6). Thus, the capital investment is recovered in 4.7 years thanks to the savings obtained by generating 2429 kW/h per month. As for the environment, it is estimated that 11,221 kg of CO2 equivalent would be released into the atmosphere without the On Grid-PV. In conclusion, the hypothesis is accepted and it is confirmed that On Grid-PV installations for Tilapia farms are technically feasible, economically viable and environmentally acceptable; their implementation would imply the possibility for aquaculture farms to produce Tilapia at a lower production cost and minimized environmental impact in terms of energy. It is recommended that aquaculture farmers in Mexico and the world implement this eco-technology that supports the sustainable development of aquaculture. Full article

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. Full article

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. Full article