Electrical Cabinet Research Articles

Computational Fluid Dynamics Modeling of Fire and Human Evacuation for Nuclear Applications

Abstract The nuclear industry has seen an increased use of computational fluid dynamics (CFD) technology as a high-fidelity tool for design-basis and beyond-design-basis accident simulations. Among its applications, CFD modeling of fire and smoke propagation in confined zones (e.g., a main control room (MCR)) is a promising approach, since detailed experimental investigation under various accident scenarios would be difficult. Egress analysis considering human behaviors is of significant importance to an effective accident mitigation strategy, and high-fidelity analysis tools now encompass these parameters in the simulation and design of emergency evacuations. In this study, the fire and smoke propagation in a MCR is modeled using the large eddy simulations (LES) code fire dynamics simulator (FDS), along with an evacuation module, EVAC to simulate the emergency egress under an electrical cabinet fire scenario. The FDS results presented in this paper constitute the first step at Canadian Nuclear Laboratories (CNL) in advancing the CFD modeling of fire and evacuation for nuclear applications.

Robotic hand-arm system for on-orbit servicing missions in Tiangong-2 Space Laboratory

PurposeThe purpose of this study is to develop a robotic hand–arm system for on-orbit servicing missions at the Tiangong-2 (TG-2) Space Laboratory.Design/methodology/approachThe hand–arm system is mainly composed of a lightweight arm, a dexterous hand, an electrical cabinet, a global camera, a hand–eye camera and some human–machine interfaces. The 6-DOF lightweight arm and the 15-DOF dexterous hand adopt the modular design philosophy that greatly reduces the design cycle and cost. To reduce the computational burden on the central controller and simplify system maintenance, an electrical system which has a hierarchical structure is introduced.FindingsThe prototypical operating experiments completed in TG-2 space laboratory demonstrate the performance of the hand–arm system and lay foundations for the future applications of space manipulators.Originality/valueThe main contributions of this paper are as follows a robotic hand–arm system which can perform on-orbit servicing missions such as grasping the electric drill, screwing the bolt, unscrewing J599 electrical connector has been developed; a variable time step motion plan method is proposed to adjust the trajectories of the lightweight arm to reduce or eliminate the collision force; and a dexterous hand uses the coordinated grasp control based on the object Cartesian stiffness to realize stable grasp. To solve the kinematic mapping from the cyber glove commands to the dexterous hand, a fingertip-position-based method is proposed to acquire precise solutions.

Fire development in multi‐compartment facilities: PRISME 2 project

Fire development in multi‐compartment facilities: PRISME 2 project

Experimental study of smoke effects on energized electrical cabinets located nearby a lubricant oil pool fire

SummaryThis paper presents an experimental study of smoke exposure effects on potential malfunction of three electrical cabinets located nearby an oil pool fire. This study was performed as part of the PRISME‐2 international OECD project. Lubricant oil was used as fire source, and three real energized electrical cabinets were used as targets exposed to smoke in the adjacent room to the fire room. The main fire properties, as well as the fire consequences, such as gas temperatures and smoke concentrations in the rooms, and the cabinets are presented in detail. The heat release rate was thus assessed at around 500 kW for nearly all the fire duration, and maximum gas temperatures reached 300°C in the fire room, and 120°C in the adjacent room. Moreover, the maximum gas temperatures and soot mass concentrations inside the cabinets ranged from 90 to 120°C and from 0.3 to 1 g/m3, respectively. Nevertheless, continuous electrical monitoring of the three cabinets did not highlight malfunction. After the experiment, monitoring test of the cabinets was conducted to investigate the potential effects. The isolation resistance of electrical circuits on the most severe smoke exposed cabinet reduced during the monitoring test. It seemed the soot deposition have caused it.

A Full-Solid-State Humidity Pump for Localized Humidity Control

Summary Humidity management is essential and widely needed in various fields. Traditional moisture removal technologies are mostly based on cooling condensation or desiccant dehumidification. These methods come with inherent defects of energy efficiency and are bulky and complex for small-space humidity-control applications. Here, we demonstrate a full-solid-state humidity pump using the advantages of commercial thermoelectric coolers and silica gel materials. Silica gel is coated on the surface of heat sinks to minimize contact thermal resistance between the material and heat source while maintaining enough heat and mass transfer area between the desiccant and the air. The humidity pump device exhibits 0.61 g W−1 h−1 humidity transfer efficiency, corresponding to a humidity transfer rate of 28.38 g h−1. The proposed device neither uses refrigerant nor introduces liquid water. It opens up the possibility of use in localized humidity control applications with higher efficiency and a wider ambient temperature range than traditional technologies.

진동대 시험을 이용한 전기캐비닛 앵커의 거동특성 분석

In this study, a shaking table test was performed to analyze the anchor behavior with or without rocking in the base plate of an electric cabinet. Two cabinets, differentiated by whether their base plates were anchored or fixed, were mounted simultaneously on a shaking table to enable a comparison of their behavior when subjected to seismic motion. Three seismic waves were used in this experiment to facilitate temporal history and resonance search. Results indicated that the impact load occurred due to mutual collision with the local mode of the cabinets’ internal components. Moreover, in the case of a single-door cabinet with a bolt fastening, it was observed that rocking mode occurred due to upliftment of the base plate. To address this problem the cabinet was tested again after being reinforced and the results achieved before and after the reinforcement procedure were discussed.

Techno Economic Modelling of Dried Black Potato (Plectranthus rotundifolius)

The techno economic modeling of dried black potato (Plectranthus rotundifolius) was studied by employing electrical cabinet oven. The parameters investigated were including parameter obtained from analysis of capital budgeting, breakeven point and financial ratio of rentability. The obtained payback period was 2 years 11 months by investing 53.000.000 rupiah for machinery and 10.000.000 rupiah for start-up cost as initial capital. By assuming 10 years of dried black potato production, the value of net present value was equal to 1.207.982.611 rupiah. The value of gross profit margin and net profit margin were 0.97 and 0.87, respectively. Regarding to the positive value of net present value, the lower payback period value, and the high value of internal rate of return (74.47%) and also the profitability index (20.17), the modeling of techno economic was positively recommending the commercial application of dried black potato by using electrical cabinet oven.

Automated Product Boundary Defect Detection Based on Image Moment Feature Anomaly

Electric distribution cabinets are critical components in the power distribution pipeline. Surface defect detection plays an important role in the production process. It not only guarantees product quality but also affects the brand reputation. In particular, the boundaries of metallic cabinets are more vulnerable to be damaged than other surface areas. Thus, boundary defect detection is a bottleneck problem that needs to be solved. To deal with this issue, a method based on image moment feature anomaly is developed to detect the defects on cabinet surfaces. The boundary edges from an image of the produced cabinet are first extracted using a hybrid of edge detection and boundary skeleton extraction. Then, the boundary areas are divided into small and identical size image blocks. A Gaussian distribution model of normal image blocks without defects is established. Finally, the anomaly features of image blocks with defects are extracted to identify the defect image blocks based on the Gaussian distribution model and a segmentation threshold. Two experiments are carried out. One is to determine the optimal illumination intensity for image acquisition and the optimal threshold of defect detection. The other is to evaluate the performance of the defect detection method. This developed approach can be applied in the non-destructive and effective inspection of electric distribution cabinets and provides a feasible solution for metallic product quality assurance.

Fragility assessment for electric cabinet in nuclear power plant using response surface methodology

Abstract An approach for collapse risk assessment is proposed to evaluate the vulnerability of electric cabinet in nuclear power plants. The lognormal approaches, namely maximum likelihood estimation and linear regression, are introduced to establish the fragility curves. These two fragility analyses are applied for the numerical models of cabinets considering various boundary conditions, which are expressed by representing restrained and anchored models at the base. The models have been built and verified using the system identification (SI) technique. The fundamental frequency of the electric cabinet is sensitive because of many attached devices. To bypass this complex problem, the average spectral acceleration ( S a ¯ ) in the range of period that cover the first mode period is chosen as an intensity measure on the fragility function. The nonlinear time history analyses for cabinet are conducted using a suite of 40 ground motions. The obtained curves with different approaches are compared, and the variability of risk assessment is evaluated for restrained and anchored models. The fragility curves obtained for anchored model are found to be closer each other, compared to the fragility curves for restrained model. It is also found that the support boundary conditions played a significant role in acceleration response of cabinet.

Technological Improvements of Grain Preparation for Milling in Small Enterprises

Introduction. In small enterprises with simplified technological process of graded milling, preparations, which involve cleaning, peeling and moistening grain, play an essential role for ensuaring high quality of graded flour. Modern equipment for the low-productive mills implies only dry cleaning of grains in an abrasive machine with their further cold conditioning. The equipment designed for graded milling with deep multiple cleaning, washing and hydrothermal treatment is not possible. It significantly increases the cost of flour. The aim of the study is to increase both qualitative and quantitative indicators of graded flour in small enterprises through peeling and drying of grains before milling. Materials and Methods. The quality analyses of grain processing according to such indicators as ash content (whiteness), moisture, quantity of fractured grains were carried out according to State Standards of the Russian Federation and the methods established in science and practice. The degree of peeling was determined by the whiteness indicator with a photoelectric whitener SKIB-M (GOST 26361-2013 “Flour. Test method for whiteness”). Grain moisture was determined according to GOST 13586.5-2015 by the drying cabinet DEC-3M (drying electrical cabinet, model type 3M). The number of fractured grains was determined according to GOST 30483-97. Results. The research result revealed the dependence of grain processing on the technical aids. А combined peeling–drying machine was developed on this principle. The authors have developed rational operations of grain processing, which increase the whiteness of the received flour on average 4–7 conventional units. The standard instrument for whiteness definition has been studied and set. According to the given results optimal operating parameters for grain processing before milling have been developed: machine productivity (Q = 700 kg/h); the period of grain processing (t = 72 s.); optimum moisture content (from the point of view of obtained flour whiteness) of grains received for milling (W = 14 %); radiant power (P = 1 000 W). Conclusions. The research proved the fact that peeling of grains is one of the most effective ways of increasing the grade of end products of small enterprises with simplified technological process of graded milling. The efficiency of peeling seeds of wheat with humidity higher than 16 % decreases that speaks for the need to dry grains. The authors of the article introduce the equipment and technology for grain processing before graded milling, which provide grain peeling and, if necessary, drying. The operating parameters of the peeling-drying machine for preparation of grains for milling have been determined. The developed technology provide, if necessary, drying the remoistened grain to necessary standards that gives the chance to produce high-quality flour from the grains processed hydrothermally without processing moisture conditions required. The machine productivity in the mode of drying should be connected with the power of microwave infrared radiation, and its time and power should be limited to a maximum permissible grain temperature, which does not exceed 60 ºС. Keywords: peeling, whiteness, moisture, drying, preparation of grain for grinding For citation: Anisimov A. V., Rudik F. Ya., Zagorodskih B. P. Technological Improvements of Grain Preparation for Milling in Small Enterprises. Vestnik Mordovskogo universiteta = Mordovia University Bulletin. 2018; 28(4):603–623. DOI: https://doi.org/10.15507/0236-2910.028.201804.603-623 Acknowledgments: The study was conducted as part of an agreement with the Foundation for Assistance to Development of Small Enterprises in Scientific and Technical Sphere (No. 180GS1 / 6784, 25 December 2014) under the “START-1” program together with “Healthy Food” LLC.

Fire spread from an open‐doors electrical cabinet to neighboring targets in a confined and mechanically ventilated facility

SummaryElectrical cabinet fire is one of the main fire hazards in nuclear power plants. As part of the OECD PRISME‐2 programme, four fire tests were carried out to investigate the fire spread from an open‐doors electrical cabinet to overhead cable trays and adjacent cabinets in a confined and mechanically ventilated facility. These tests, named CFS‐5 to CFS‐7 and CORE‐6, used same both cabinet (fire source) and three overhead cable trays. The trays were filled with a halogenated flame‐retardant cable‐type for CFS‐5 and one halogen‐free for the three other tests. Moreover, fire dampers were used for CFS‐7 test while CORE‐6 test implemented two additional cabinets adjacent to the fire source. Measurements such as flame and gas temperature, gas concentration, mass loss rate, and heat release rate were performed for investigating the fire spread. Cabinet fire spread to the cable trays for CFS‐5 and CFS‐6 tests. Three fast and short cable tray fires were shown for CFS‐5, while a slow and long cable tray fire was highlighted for CFS‐6. In contrast, the fire dampers shutdown for CFS‐7 test prevented ignition of the overhead cables. Furthermore, for CORE‐6 test, cabinet fire spread to the adjacent cabinets, but the upper cables were not ignited.

ANALYSIS OF EXISTING AND JUSTIFICATION OF APPLYING NEW AUTOMATIC SYSTEM FOR FIRE-AND-EXPLOSION PREVENTION AT VESSELS, SHIPS, OFFSHORE OIL PLATFORM

Introduction. A brief analysis of catastrophic fires and explosions on the offshore oil platform, ships and vessels is performed. It’s shown the relevance of the qualitative improvement of marine fire equipment. Analysis of modern fire fighting systems on vessels, ships: sprinkler, deluge, gas and pneumatic-impulse fire extinguishing systems is carried out. It’s substantiated new equipment for upgrading existing systems — subsystems of multi-module pulse, vortex combined quenching for the protection of ships, vessels, tankers, offshore oil platforms. The choice of the arrangement of modules based on the results of polygon tests is described. There are created systems of modules for the upper decks, engine rooms, holds, corridors, gangways, sections, electrical cabinets, etc.The modules create gas-water squalls, gas-powder vortices that extinguish all fires and continuous fires in all or part of the compartment and deck in seconds. The participation of pilot modules in operations for eliminating the consequences of disasters in hard-to-reach zones of collapses, with high levels of radioactive and toxic contamination in emergency locations is described.Description and analysis of experiments. The recommendations on the use of multi-barrel modules based on the analysis of experiments on the creation of fine-dispersed water squalls for extinguishing developed fires of classes A, B, C, F, the inhibition of explosive vapor-air clouds, the deposition and detoxification of gas-air clouds of ammonia and chlorine are substantiated and developed. The localization and liquidation of oil and oil products are described. The possibility of reducing the cost of liquidation of 1 sq m of bottling from $ 20-40 to $ 1-3 is shown, and reducing the time for liquidation of bottles to 5-10 times, which in a more multiple degree will reduce material and environmental losses from oil bottling.Conclusion. The advantages of introducing new technology and techniques for eliminating the consequences of accidents at sea and preventing their development into a catastrophe are summarized.

Condition monitoring and fault diagnosis of electric submersible pump based on wellhead electrical parameters and production parameters

ABSTRACTElectric submersible pump (ESP) has become an important mechanical oil equipment in the digital oil field, and it is necessary to perform the condition monitoring and fault diagnosis on the ESP system. An on-line technique is proposed based on the electric parameters and production parameters. To realize the fault diagnosis of the ESP in the ground, the algorithms are designed by feature extraction, and the algorithms combine the electric parameters in the electric cabinet with the production parameters, which are separated by a newly designed gas–liquid two-phase flow meter. Meanwhile, electrical parameters are the main ones and production parameters are the auxiliary ones. The parameter features are extracted from different faults by digital signal processing, and the study accurately monitors nine typical operating conditions of the faults. Importantly, the method enormously reduces the impact on the sensors in the down hole, and the test data show that the method has the advantages of low cost and high efficiency.

Development of a Low Cost Power Meter Based on A Digital Signal Controller

AbstractThe monitoring of power quality is a central topic for both household electrical and industrial equipment. Typically, the lacks of quality in a power system (both a public mains and an industrial power supply network) involve interruptions and deviations of the actual supply signals from the nominal characteristics, with potential annoying effects in electrical power systems and problems in industrial and communication apparatus. In this paper, the design and implementation of a measuring system based on a high-performance microcontroller that carries out the power quality analysis of the mains is presented. The system measures the fundamental parameters related to the system under monitoring, that can be a single or a three phase network. The proposed measurement instrument is mainly based on the Microchip PIC32MZ2048ECH100 Digital Signal Controller (DSC) and the Texas Instruments ADS8558 A/D converters (ADCs). Starting from voltage and current sampled values, simultaneously acquired by the converters, the DSC calculates the following parameters: frequency; RMS voltage; RMS current; phase shift; active power; reactive power; apparent power; THD. The measured parameters are also externally transmitted via a serial link. In the paper a prototype of the proposed instrument is described. It is linked to a PC and results shown on a LabVIEW based user interface, reporting also results from lab tests during the metrological characterization phase. Its main features (cost effectiveness, reduced dimensions and low power consumption) make it suitable for installation into existing electric cabinet of civil and commercial users. The continuous and real-time monitoring capability, managed both locally or remotely, is one of the most interesting features.

Seismic fragility analysis with artificial neural networks: Application to nuclear power plant equipment

The fragility curve is defined as the conditional probability of failure of a structure, or its critical components, at given values of seismic intensity measures (IMs). The conditional probability of failure is usually computed adopting a log-normal assumption to reduce the computational cost. In this paper, an artificial neural network (ANN) is constructed to improve the computational efficiency for the calculation of structural outputs. The following aspects are addressed in this paper: (a) Implementation of an efficient algorithm to select IMs as inputs of the ANN. The most relevant IMs are selected with a forward selection approach based on semi-partial correlation coefficients; (b) quantification and investigation of the ANN prediction uncertainty computed with the delta method. It consists of an aleatory component from the simplification of the seismic inputs and an epistemic model uncertainty from the limited size of the training data. The aleatory component is integrated in the computation of fragility curves, whereas the epistemic component provides the confidence intervals; (c) computation of fragility curves with Monte Carlo method and verification of the validity of the log-normal assumption. This methodology is applied to estimate the probability of failure of an electrical cabinet in a reactor building studied in the framework of the KARISMA benchmark.

Electricity meter sensitivity and precision measurements and research on influencing factors for the meter measurements

Methodology, equipment, precision, immunity to electromagnetic emissions and reliable measurement results are important questions for electrical energy measurements. Widely used smart energy meters show good results under laboratory tests and in ordinary applications, but are not very suitable for industrial digital electrical energy supply environment. A different method and inexpensive equipment are used to overcome the above mentioned. The measured power balance between 15 robotized manufacturing cell measurement points (only power losses not measured are the ones in cables) varies in a range of 1,8% (measurement data rate- 20ms), despite the high level of electromagnetic emissions inside and outside of electric cabinets created by power converters.

PLC Electric Control System of CNC Machine Tool

This paper studied the design of PLC electrical control system of CNC machine tool. The design program of the electrical control system is established according to the requirements. The parameters of all electrical components are determined through calculation of electric load for selection of electrical equipment and wires. Then the design of power supply and distribution of the electrical control system is described in detail, and the design of the electrical control system of main equipment is studied. This paper focuses on the design of spindle, feed axis and module. In addition, this paper summarized the design of the electrical control cabinet, wiring, installation and commissioning of electrical equipment, inspection of the machining effect after installation and the control system. The entire CNC machine tool electrical control system is designed.

Computational Analysis of Fire Dynamics Inside a Wind Turbine

Wind turbines are generally considered cost-effective, reliable and sustainable energy sources. Fires are not common in wind turbines, but a significant number of fires occur every year due to the large number of turbines installed. Wind turbine fires are difficult to extinguish hence significant damage is expected. Due to the unmanned operation, the probability of a turbine being occupied during a fire is very low. However, operators can do several tasks every week, and hence be exposed to a certain risk. Moreover, there is a general lack of information about how a fire develops inside a wind turbine and the subsequent evolution of the tenability conditions during the time required for an eventual evacuation. Gamesa has been working on fire safety since 2013, using CFD fire modelling to provide insights on wind turbine fire development for the design of emergency procedures. The paper describes a fire hazard analysis performed in a Gamesa’s 2.5 MW turbine. A CFD simulation is carried out to estimate the effects during the first minutes of a typical wind turbine fire in an electrical cabinet. Results show that average oxygen concentration at the nacelle remains above 19.5% during the first 10 min; temperature remains below 60°C for 12 min if measured at 1.5 m; and visibility is on average assured at heights lower than 1.5 m, with values above 5 m during the first 8 min in worse locations, implying no danger for personnel. The potential of this type of analysis to design safer wind turbines under performance-based approaches is clearly demonstrated.

Simulation Research on Temperature Rise of Meter Cabinet Using ANSYS

Meter cabinet was the abbreviation of electric energy meter cabinet, and it was a kind of device for measuring electric energy. In the long-term use of the metering cabinet often occurs the problem of excessive temperature. In order to improve the temperature rise of the meter cabinet, the temperature field was simulated and analyzed. Using the simulation software ANSYS Workbench can simulate the temperature field of the conductor of the meter cabinet. By changing different conductor materials and temperature simulation of the contact position of the conductor, the distribution of temperature was analyzed. According to the maximum of the distribution of the Joule heat and the highest temperature distribution, the best scheme was choose. In addition, the simulation of the eddy current field was carried out on the panel of the meter cabinet, after comparing and analyzing the simulation results and selecting the best panel material.

An optical sensor for hydrogen sulfide detection in open path using WMS-2f/1f technique

An optical hydrogen sulfide (H2S) sensor based on wavelength modulation spectroscopy with the second harmonic (2f) corrected by the first harmonic (1f) signal (WMS-2f/1f) is developed using a distributed feedback (DFB) laser emitting at 1.578 μm and a homemade gas cell with 1-m-long optical path length. The novel sensor is constructed by an electrical cabinet and an optical reflecting and receiving end. The DFB laser is employed for targeting a strong H2S line at 6 336.62 cm-1 in the fundamental absorption band of H2S. The sensor performance, including the minimum detection limit and the stability, can be improved by reducing the laser intensity drift and common mode noise by means of the WMS-2f/1f technique. The experimental results indicate that the linearity and response time of the sensor are 0.999 26 and 6 s (in concentration range of 15.2—45.6 mg/m3), respectively. The maximum relative deviation for continuous detection (60 min) of 30.4 mg/m3 H2S is 0.48% and the minimum detection limit obtained by Allan variance is 79 μg/m3 with optimal integration time of 32 s. The optical H2S sensor can be applied to environmental monitoring and industrial production, and it has significance for real-time online detection in many fields.