Automatic Shutdown Research Articles

Methodology for determining the technical condition of the pulse power supply unit in dynamic mode

Since the power supply unit is an integral part of any electronic device, to ensure high quality and reliability of its operation, it is necessary to periodically check its operational characteristics and the structural solutions used in it. The lack or untimely verification procedures jeopardizes the functioning of the entire device and leaves the user vulnerable to the likely onset of sudden failures and subsequent potentially unpleasant situations. It should be borne in mind that the element base (workmanship) of the power supply units does not differ from the quality of the element base of the entire device, while this unit is an intermediary between the power supply network (parameters of the characteristics and state of the power supply network) and the main device (technical condition and adequacy of the user when using it). Therefore, the durability of the main equipment depends on the efficiency and correctness of the functioning of the power supply, the stability of its parameters. In case of a critical state of the equipment, the power supply unit itself contains a fuse (automatic emergency shutdown system), while the operation of the fuse does not allow to determine the cause (source) of the critical state (network - power supply unit - main equipment - violation of operating rules). Replacing the fuse, or replacing the power supply does not guarantee the final solution to the problem of technical diagnostics. Given the ever-increasing complexity and high cost of modern electronic devices (including those with elements of artificial intelligence), the issue of timely diagnosis of potential power supply malfunctions is critically important. Therefore, the development of scientifically sound approaches to determining the technical condition of power supplies and localizing its faults is an urgent task

Active disturbance rejection control of pressurizer pressure during startup process in a pressurized water reactor nuclear power plant

To cope with the participation of power plant peak shaving and realize the diversification of nuclear energy applications including cogeneration, desalination, etc. The application of automatic procedure startup and shutdown system (APS) is an important research direction to improve the safety, economy and flexibility of pressurized water reactor (PWR) nuclear power plant (NPP). But it is difficult to realize automatic control of pressurizer pressure in the PWR NPP startup condition with drastic changes and disturbances. To solve this problem, an active disturbance rejection control (ADRC) algorithm was proposed for the pressure control of the pressurizer. The controller parameters were tuned based on a two-step tuning scheme. Its control performance and disturbance rejection ability were studied and compared with proportional-integral-derivative (PID) controller under different operation conditions. The simulation results showed that the designed controller with fixed parameters can outperform the PID controller with specific optimized parameters on setpoint tracking and disturbance rejection. This study is of great significance for realizing the automatic control of pressurizer pressure in the startup process, and can provide reference for the design of the automatic control system during PWR startup. The controller was applied in typical startup process and achieved satisfactory control performance.

Метод оценки критериев оптимизации системы электробезопасности в инфраструктуре села

The article provides an analysis of the state of energy availability and equipment of electric installations for infrastructure facilities in rural settlements. The main type of technogenic hazards is marked – the electrical hazard that occurs in emergency modes of operation of electrical installations. The conditions for solving the safety problem and choosing the optimal variant of the electrical safety system are given. The indicators of the technical efficiency of the electrical safety system are determined, characterized by the likelihood of electrical injury to a person and the likelihood of a fire in electrical installations at facilities. The choice of the most appropriate options for the use of electrical protection equipment, providing for the joint use of automatic switches and protective shutdown devices, was made as a result of comparing the likelihood of electrical injury and fire with a normalized risk level of electrical and fire safety. A method for optimizing the electrical safety system is considered according to two particular criteria representing the average values of the probabilities of electrical injury and fire with the equivalence of their values. The task of optimizing the security system is indicated, which consists in constructing a vector criterion of optimality and converting it into a scalar criterion using the "assignment" method to obtain a normalized partial criterion. The normalized private criteria of electrical and fire safety are determined using a scalar criterion for the selection of electrical protection options for an agricultural facility. An algorithm for evaluating the effectiveness of the electrical safety system in dangerous situations of electrical injuries has been built. The description of the construction of an algorithm for modeling the state of fire safety of the system in the event of fires in electrical installations is given. A comprehensive assessment of the normalized criterion for optimizing the electrical safety system was obtained according to two normalized criteria for electrical and fire safety and the choice of optimal electrical protection options at the studied facility. Keywords: TECHNOGENIC HAZARD, ELECTRICAL INSTALLATION, ACCIDENT, ELECTRICAL INJURY, TECHNICAL EFFICIENCY, EVALUATION CRITERIA, OPTIMIZATION OF ELECTRICAL SAFETY SYSTEM, ELECTRICAL PROTECTION

Research on Fixed-Slope On-Chip Soft-Start Method Applied to Buck DC–DC Converter

A fixed-slope soft-start method applicable to Buck converters for on-chip integration is proposed to address the issue of varying power stresses (device voltage, current stress) during start-up with different output voltages. The main mechanism involves combining feedback coefficient sampling with a fixed-slope reference voltage to achieve a slow rise in the reference voltage by equating the soft-start charging current to a pulse current through the on-chip integration of a small capacitor. This allows for fixed-slope start-ups for different set output voltages. Spike elimination techniques are employed to address charging current spikes caused by pulse periods, enhancing precise control over the soft-start time. By replacing the traditional resistor divider network with a capacitive divider network in the soft-start method, DC power consumption is minimized. Upon completion of the soft start, a smooth transition to a steady-state operation occurs, with the automatic shutdown of the soft-start module reducing static power consumption. A specific circuit design and layout verification based on 0.18 μm high-voltage BCD technology demonstrates that the proposed method maintains a fixed-slope start-up of approximately 5 mV/μs within the chip’s output range of 0.9 V to 4 V, with a slope control accuracy of up to 98%. The soft-start circuit effectively eliminates surge currents generated during start-up under full load conditions of 3 A and no-load conditions of 0 A, reducing the overall surge current by 44% and enabling a stable voltage rise and the smooth transition to a steady-state operation.

Factory Worker Alcohol Detector with Automatic Machine Shutdown

Factories are machine critical industries. Factories run on two major resources, machines and labour. Machines need to be operated carefully since one mistake may lead to injuries or loss of life and business. Large industrial machines that run on high power are even critical since a mistake in operating it may lead to huge losses. Here we propose an automated system to detect alcohol consumption of factory workers and machine shutdown with alerting system. Consumption of alcohol affects the mental state of person. A person operating heavy machines under the influence of alcohol is likely to hurt himself as well as the machine. So, we use a microcontroller-based circuit that consists of alcohol sensor interfaced with it. Also, we have an LCD display. The entire system is powered by a 12V supply. The alcohol sensor is constantly running to check if worker is drunk. The alcohol sensor can sense the alcohol level and outputs a voltage according to the alcohol sensed. The microcontroller interfaced to it reads the value and if it is found to be above permissible range it goes into alerting mode. Once it enters alerting mode the microcontroller stops machine operated by the worker and displays the status of alcohol alert on LCD display. Also, it sounds a buzzer to indicate the same. It now shuts down the motor used to demonstrate as the machine

Control system for suction valves within gas compressors skids located in potentially explosive zones

The paper presents the implementation of a feedback loop controller for the suction valves used within the gas compressors skids manufactured by Romanian Research and Development Institute for Gas Turbines COMOTI. These compressors are installed at beneficiaries, in potentially explosive environments (e.g., gas extraction and transportation applications). The proposed solution addresses the problems observed due to the high suction pressures of screw compressors, which may occur at start-up or during operation, leading to failed start-ups or emergency shutdowns. An automatic sequence implemented in the control software and displayed on the operating panel, could assist the operator during high suction pressures (above 1.2 bar). These pressure conditions normally lead to alarm limits and to performing an automatic shutdown sequence for protecting the compressor. The paper herein discusses the implementation of a start-up sequence in the programmable logic controller’s software, which can be applied without critical interventions on the compressor packages, only through minor control software modifications which can safely extend the inlet pressure range and the exploitation of the compressors. Thus, since no hardware modifications are required, we also ensure maintaining the ATEX certifications of equipment and assemblies.

Quantitative risk assessment of China's first liquid hydrogen refueling station.

Hydrogen refueling stations (HRSs) are among the most important infrastructures for fuel cell vehicles. However, the safety issue of HRSs has become a key constraint to the wide application and development of hydrogen energy. This article presents a quantitative risk assessment of the first liquid HRS (LHRS) in China and conducts a comprehensive assessment in terms of both individual (IR) and societal risks (SRs). The results showed that both the IRs and SRs related to the LHRS exceeded the risk acceptance criteria. The rupture of the flexible hose of the dispenser and the leak from the compressor are the main contributors to these risks. On the other hand, implementing appropriate mitigation measures on the level of the LHRS dispenser and compressor, including the addition of breakaway couplings in the flexible hose of the dispenser, the installation of hydrogen detection sensors, the arrangement of automatic and manual emergency shutdown buttons, and the elevation of the compressor, is capable of reducing the risk of the LHRS to be within the risk acceptance criteria.

Amorphous Silicon Thin-Film Solar Cells on Fabrics as Large-Scale Detectors for Textile Personal Protective Equipment in Active Laser Safety.

Laser safety is starting to play an increasingly important role, especially when the laser is used as a tool. Passive laser safety systems quickly reach their limits and, in some cases, provide inadequate protection. To counteract this, various active systems have been developed. Flexible and especially textile-protective materials pose a special challenge. The market still lacks personal protective equipment (PPE) for active laser safety. Covering these materials with solar cells as large-area optical detectors offers a promising possibility. In this work, an active laser protection fabric with amorphous silicon solar cells is presented as a large-scale sensor for continuous wave and pulsed lasers (down to ns). First, the fabric and the solar cells were examined separately for irradiation behavior and damage. Laser irradiation was performed at wavelengths of 245, 355, 532, and 808 nm. The solar cell sensors were then applied directly to the laser protection fabric. The damage and destruction behavior of the active laser protection system was investigated. The results show that the basic safety function of the solar cell is still preserved when the locally damaged or destroyed area is irradiated again. A simple automatic shutdown system was used to demonstrate active laser protection within 50 ms.

Study on Coal Mine Safety Monitoring and Alerting System Using IOT

Abstract: A coal mine safety monitoring and alerting system using IoT can help improve safety in coal mines by providing realtime monitoring and alerting of hazardous conditions. The system can use various sensors and devices to monitor parameters such as gas concentration, temperature, humidity. The data from these sensors can be collected, processed, and analyzed using an IoT platform to provide insights into the condition of the mine. The system can also incorporate a range of alerting mechanisms to notify mine workers and supervisors of any hazardous conditions For example, the system can use audio and visual alarms, mobile notifications, and even automatic shutdown of machinery in case of danger. The system utilizes various sensors and devices to monitor parameters such as gas concentration, temperature, humidity, and collects, processes, and analyzes the data using an IoT platform. The system aims to reduce the risk of accidents and injuries to mine workers, increase productivity, and reduce downtime.

A Critical Review of Fire Tests and Safety Systems in Road Tunnels: Limitations and Open Points

Fire tests are used to determine whether fire protection products meet the minimum performance criteria set out in codes and legislation, as well as to certify these products. Experimental large-scale fires are used to test the performance of safety systems in tunnels, which are confined environments with a high probability of accidents and significant consequences due to the evolution of the event and whether there is the capability of counteracting it by safety measures. In this study, we conducted a systematic literature review following PRISMA guidelines. We searched the Scopus and Web of Science databases for publications from 2013 to 2022, resulting in a selection of 72 articles. An analysis was conducted on the following main topics: tunnel fires, fire characteristics (measured variables, spread, and smoke), model-scale tests, automatic shutdown systems, and ventilation solutions. One of the most important contributions of this study is the suggestion that fire tests represent an effective method not only to prevent fire events in tunnels but also to ensure the resilience of the infrastructure. Based on this state-of-the-art literature review, future tunnels could be designed by linking new smart technology and artificial intelligence to create interactive and high-performing safety systems.

Hydrogen hazards and gas detection—Electrolyzer case study

AbstractHydrogen is a strong candidate for fueling the green energy transition. Hydrogen, like all stores of potential energy, can be dangerous if not handled properly. The most common, and rapidly growing, source of green hydrogen is electrolysis of water. Electrolyzers split the water molecule into hydrogen and oxygen molecules. Hydrogen is flammable while oxygen is an oxidizer. If hydrogen escapes, a hazardous condition can be generated, which may have significant safety consequences. As a result, a commonly employed safeguard is a gas detection system with automatic shutdowns. This paper presents an overview of the hazards of hydrogen generation through electrolysis, and then presents a case study of the design of a gas detection system for an electrolyzer facility. The design of the gas detection system included using gas detection mapping approaches recommended by ISA TR 84.00.07 for placement of the required detectors along with recommendations by IEC 61511 for the design of the associated automatic shutdown of the electrolyzer and return to a safe state.

Basics of safety and organization of the workplace during the operation and repair of compressors at the enterprises of ATP

For many decades, any organization involved in the operation and maintenance of vehicles cannot imagine its activities without compressor units. Compressors are used in all sectors of the national economy, and are valued for their reliability, high efficiency, long service life. The scope of the equipment is very wide, without it the work of any large industrial enterprise is indispensable. Compressors are used in mechanical engineering, metallurgy, oil and gas industry, car services, construction and other industries. Each compressor unit is equipped with an emergency protection system that provides: automatic shutdown of the compressor; sound and light alarm. According to the requirements of the Rules, all compressor units are equipped with instrumentation: pressure gauges for measuring pressure, thermometers or other sensors for measuring temperature. The compressor is placed in a separate room, which should not be connected with the premises where explosive and chemically hazardous industries are located. In the premises of compressor units, it is not allowed to place equipment and equipment that are technologically and structurally not related to compressors.

Fault analysis and troubleshooting of nitrogen supply system for a ship’s nitrogen generator

This paper introduces the working principle and system work flow of the marine nitrogen generator. Emphasis is laid on the air pretreatment subsystem, nitrogen membrane separation subsystem and automatic control system of the nitrogen generator. In view of the automatic alarm shutdown fault of a ship’s nitrogen generator in the course of operation, the reason is analyzed, and it is found that the refrigeration device fault of the nitrogen generator leads to the excessive air temperature before the film inlet group, thus causing the failure shutdown. Finally, the fault location and troubleshooting are carried out.

Development and application of unplanned automatic shutdown fault tree model of nuclear power plant

In order to improve the operation performance of nuclear power plants, this paper introduces a modeling method of unplanned automatic shutdown of nuclear power units based on Fault Tree Analysis, and takes the shutdown signal of steam generator water level low-low as an example, analyzes the development process and application scenarios of unplanned automatic shutdown fault tree in detail. The results show that this method solves the huge and complex problems in the fault tree model of unplanned automatic shutdown in nuclear power units, and can be used to comprehensively and systematically identify the components that affect unit power generation. At the same time, combined with quantitative data, it can monitor the risk of unit power generation, and achieve targeted and efficient improvement of equipment reliability management level and power generation performance level.

Design of Hydraulic System of Microcomputer Governor for Small Turbine

Taking a power station as an example and according to the technical and performance requirements of the turbine governor in small rural hydropower stations, a hydraulic station with high oil pressure is designed by adopting a highly reliable general PLC as the control device and using standardized hydraulic components; Taking into account requirements for regulating performance under the conditions of automatic regulation, manual regulation and emergency shutdown, and the reliability requirements, the hydraulic control circuit with automatic adjustment, manual adjustment and emergency stop is designed to avoid possible problems of hydraulic system by taking effective measures. The product based on the design have been developed and put into production to meet the requirements of industry standard and its application with good effect can be further promoted.

Comparison of Deep Reinforcement Learning and PID Controllers for Automatic Cold Shutdown Operation

Many industries apply traditional controllers to automate manual control. In recent years, artificial intelligence controllers applied with deep-learning techniques have been suggested as advanced controllers that can achieve goals from many industrial domains, such as humans. Deep reinforcement learning (DRL) is a powerful method for these controllers to learn how to achieve their specific operational goals. As DRL controllers learn through sampling from a target system, they can overcome the limitations of traditional controllers, such as proportional-integral-derivative (PID) controllers. In nuclear power plants (NPPs), automatic systems can manage components during full-power operation. In contrast, startup and shutdown operations are less automated and are typically performed by operators. This study suggests DRL-based and PID-based controllers for cold shutdown operations, which are a part of startup operations. By comparing the suggested controllers, this study aims to verify that learning-based controllers can overcome the limitations of traditional controllers and achieve operational goals with minimal manipulation. First, to identify the required components, operational goals, and inputs/outputs of operations, this study analyzed the general operating procedures for cold shutdown operations. Then, PID- and DRL-based controllers are designed. The PID-based controller consists of PID controllers that are well-tuned using the Ziegler–Nichols rule. The DRL-based controller with long short-term memory (LSTM) is trained with a soft actor-critic algorithm that can reduce the training time by using distributed prioritized experience replay and distributed learning. The LSTM can process a plant time-series data to generate control signals. Subsequently, the suggested controllers were validated using an NPP simulator during the cold shutdown operation. Finally, this study discusses the operational performance by comparing PID- and DRL-based controllers.

Troubleshooting and Improvement of Mechanical Overspeed Shutdown of Diesel Generator

This paper introduced the components and functions of control components of a ship automatic power station, with an analysis of the control principle of such station. The fault treatment method and troubleshooting process are elaborated based on mechanical overspeed automatic shutdown fault of the generator. Finally, in view of the problem of 4K6 relay, appropriate improvement measures are proposed.

НЕОБХОДИМОСТЬ ВНЕДРЕНИЯ ЭНЕРГОНЕЗАВИСИМЫХ СИСТЕМ ОТКЛЮЧЕНИЯ ГАЗО-, ВОДО- И ЭЛЕКТРОСНАБЖЕНИЯ В СЕЙСМООПАСНЫХ ЗОНАХ

The article is devoted to the analysis of problems in the occurrence of difficult to predict natural emergencies. The issues related to the use of the system of automatic shutdown of gas, water and power supply at industrial enterprises and residential premises are considered. It has been established that the automatic shutdown system should have the smallest time delay. Particular attention should also be paid to autonomy and energy independence. The analysis showed that during an earthquake, a system using a “gravitational energy accumulator” can be used, which will allow obtaining the shortest time delay, and such a system does not require any additional energy consumption, special control and maintenance.

ENERGY SAVING AS AN INDICATOR OF ENERGY EFFICIENT PRODUCTION

The increase in utility prices in Russia occurs every year. In modern society, as well as in the production sector, saving are the main indicator of successful development. (Research purpose) The research purpose is analyzing an automated system for the technical accounting of energy resources, which is designed to help the enterprise redistribute the load from the main time, when the price is high, to the night, when the price is lower. (Materials and methods) Manufacturing enterprises are trying to reduce their energy costs, monitor all saving innovations and use them in their activities. (Results and discussion) The companies try to use: strict requirements for control over the lighting in the entire building, automatic shutdown devices, constantly updates the equipment. Enterprises mainly use the same technologies to save electricity. Some enterprises use direct savings of electric energy, which leads to a reduction in costs due to equipment; installation of such equipment can only be carried out with available energy consumption data. In order to get these data, a special automated information and measurement system is used. (Conclusions) The choice of each electric motor should be individual, only if the specified parameters are met and the goals for saving electricity are realized, an entrepreneur can count on leading positions in a competitive market. The automated information and measurement system opens up a number of advantages for saving electrical energy.

Poboljšanje standardizovane procedure za verifikaciju kvaliteta niskonaponskih električnih instalacija

Periodic verification of the quality of low-voltage electrical installations is very important from the point of view of safety of people in the building from electric shock and initial fire caused by failures of low-voltage electrical installations (usually poor electrical contact). The standardized procedure for verifying the quality of electrical installations by electrical measurements involves checking which can determine with certainty only whether the protection system by automatic shutdown of the power supply in case of failure is effective or not. However, this check can only detect some poor electrical contacts in the circuit that are potential causes of fire. The paper provides an overview of research results conducted within the project of the Ministry of Education, Science and Technological Development of the Republic of Serbia (project record number 36018), on the basis of which the correction of the existing procedure of periodical verification of the quality of electrical installations is proposed. The proposed correction, which was developed based on the experience gained by performing periodical verification of the quality of electrical installations in the field, as well as analysis of measurement results obtained experimentally in laboratory conditions, allows poor electrical contacts to be detected in a timely manner.