Safe Operation Level Research Articles

Error state prediction of capacitor voltage transformer based on TimesNet and gate control unit

The stability and reliability of the error state of capacitor voltage transformer (CVT) are poor, which affects the fairness of electricity trade settlement and the safe operation level of power grid. However, the CVT error data is superimposed by different periodic information such as daily period, monthly period and quarterly period, which makes the prediction of transformer error state challenging. In this paper, a CVT error state prediction method based on TimesNet and gate control unit (GRU) is proposed. The TimesNet network is employed to capture the intraperiod-variation and interperiod-variation characteristics of the ratio difference data of a-phase, b-phase and c-phase, and the feature data and GRU model are employed to predict the output. The simulation results demonstrate that the mean square error (MSE) and mean absolute error (MAE) of the proposed model are 0.0002 and 0.0101, respectively, indicating that this model has lower prediction error and higher prediction accuracy.

Research on 750kV Reactor Vibration Based on Electromagnetic-mechanical Field Coupling Finite Element Model

The vibration signal characteristics of a 750kV shunt reactor with high voltage level and high vibration amplitude is one of the important indexes to evaluate the operating condition of the reactor. Since the high level of safe operation with Ultra-high voltage power equipment, it is challenging to collect long-term and extensive vibration signal data under safe operating conditions. This paper establishes the electromagnetic-mechanical field coupling finite element model (FEM) of a 750kV shunt reactor under a COMSOL open-source simulation environment. The resonance effect of magnetostriction of the iron core and the Maxwell forces between the iron core discs on the reactor structure is analyzed. The vibration distribution and typical frequency characteristics of each part of the 750kV shunt reactor are analyzed to provide a reference for the research of vibration fault diagnosis of Ultra-high shunt reactor.

“Designation of operational restrictions for harbour ships on inland waterways

The existing approaches to assignment of operational restrictions for inland vessels with regard to maritime areas, as well as for inland waterways, are analyzed in the paper. The methodology for assessing the feasibility of organizing the operation of inland and mixed river-sea-going ships in wave-sheltered waters in maritime areas is studied. The additional limitations regulated by the Guidance R.015-2006 of the Russian Classification Society for such vessels while exploiting in regimes of port navigation in sea regions are con-sidered. Research of peculiarities of wave formation on inland waterways has showed that in coastal areas the local winds and topography have significant influence. For limited water areas there are no up-to-date refer-ence data on long-term wave and wind characteristics. Executed analysis has shown that for the decision of a problem on definition of permissible conditions of ships operation on the protected water areas on internal waterways in a port navigation mode, the approach earlier used for the Guidance requires essential changes. A list of parameters to be taken into account when justifying the conditions of inland navigation vessels opera-tion in sheltered waters has been defined. Calculated dependence of an estimation of modes of the established wave in the limited water areas on which realization of a mode of port floating on inland waterways is possi-ble is offered. Ranges of calculation limits for ships of the classes under review are determined. The required level of safe operation of inland waterway vessels in the basins, the rank of which doesn't correspond to the class of the vessel, is substantiated. The study results are recommended for inclusion in the regulatory frame-work of the Russian Classification Society.

Study on the Characteristics, Harm, Mechanism and Prevention Measures of Corrosion at the Tower Foot of Transmission Line

The transmission line is the key medium and channel for power transmission from the power supply side to the power consumption side. As the infrastructure supporting the transmission line, the iron tower is crucial for the safe and stable operation of the grid. In recent years, the phenomenon of corrosion at the foot of power transmission towers has been expanding, which is a major hidden danger affecting the security of the power grid. Based on the actual situation, this paper summarizes the corrosion characteristics of the current transmission line tower foot and points out the harm and reaction mechanism of tower foot corrosion. According to the existing technical conditions, the corrosion prevention measures for the tower foot are proposed to eliminate the hidden danger of tower corrosion from the root and improve the safe operation level of transmission lines, which can be used for reference by relevant personnel.

Aspects of Design in Low Voltage Resilient Grids—Focus on Battery Sizing and U Level Control with P Regulation in Microgrids of Energy Communities

Energy communities and their resiliency are both relatively new subjects of interest that need deeper analysis. The concepts are emerging in the current trend of energy decarbonization, combined with unpredictable external factors, such as extreme weather, or nearby conflicts, such as wars. To be resilient against electrical network supply outages or heavy blackouts, energy communities need appropriate design of their electrical microgrids to maintain an acceptable level of activity in both normal and critical situations. The paper deals with aspects of the design of the electrical network used by energy communities, seen as microgrids designed to offer an acceptable level of safe operation and energy resilience. While electrical network resilience covers both the public network (main grid) and local microgrid of an energy community, the paper focuses on the safe operation and resilience related to the local microgrid as a distinct goal from the one of preserving the main grid’s functionality. The first section considers definitions of energy resilience and some of the existing preoccupations on the subject. A second section of the paper presents different aspects of the design of a microgrid, with the purpose of increasing its safety in operation and energy community resilience. The section addresses electrical network architectures, multiple roles of storage resources related to prosumers and to islanded microgrids with high-RES penetration, and other aspects such as the impact of electrification of heating through, e.g., heat pumps. The next sections present selected use cases, which develop some of these design aspects by using typical real data for the analysis and assessing solutions to address resilient microgrid challenges. The selected use cases consider simplified approaches for real-time and short-term storage needs and operational use in microgrids, maintaining voltage levels in a high-RES scenario by using battery P control, and optimization of storage resources to cope with the needs. Conclusions are given in a final section, which also presents future work for a presumed continuation with other use cases related to storage means, safe operation, and resilient design of energy communities microgrids.

Research and development of bunton structures of double-row rope-profile guides for movement of lifting cages

The paper studies the existing options of rigid reinforcement of vertical shafts, consisting of buntons and guides of various types, which ensure the movement of vehicles in the shaft reinforcement with double-row rope-profile guides. We have considered various layouts and structures of tiers for various number of vehicles moving in the shaft and their purpose (skips, cages, counterweights), and analyzed their advantages and disadvantages. On the basis of analysis and research, the structures of buntons for double-row rope-profile guides and the legs with grips have been developed that allow the guides to move up and down relative to the tier, to transfer horizontal dynamic forces in the frontal and lateral planes. Research, analysis, development and implementation of bunton structures for double-row rope-profile guides and implementation with connecting rods, frames, which provide greater reliability while maintaining all the necessary clearances (according to the Safety Rules) between the vehicles and the shaft lining, in the "vehicle-reinforcement" system. Using the results of these studies in the development of existing structures will achieve the following results: - increasing the safety level while observing the standard clearances in the elements of shaft reinforcement; - reducing capital costs due to a decrease in the metal consumption of the tier of shaft reinforcement; - reducing the labor intensity of maintenance and repair by reducing the number of buntons and their fastening elements; - reducing the effect of clogging and corrosion on the durability of rope-profile guides and buntons; - reducing the impact of shaft lining violation on the reinforcement; - increasing the reliability level of kinematic connection in the "guide-bunton" system; - providing standard clearances in the shaft section at a safe level; - ensuring a high reliability level and safe operation of the shaft reinforcement with rope-profile guides. The implementation of developed structures of double-row rope-profile guides of the vertical shaft reinforcement will lead to an increase in the level of safe operation, while reducing the metal consumption and the cost of maintenance and operation of the vertical shaft reinforcement.

Research on a Wireless Temperature Measuring Device Using Inductive Power

With the advancement of urban construction, more and more distribution network lines are changed from overhead lines to cable lines. Currently, the distribution network cable connection generally adopts the European or American cable elbow. If the temperature changes inside the cable elbow can be monitored in time, it will help to find the hidden fault of the cable elbow in time and improve the safe operation level of the power grid. In this paper, the online temperature measurement device of distribution network cable is discussed and researched, and a contact-type inductive wireless temperature measurement sensor suitable for the elbow joint of distribution network cable is designed. The sensor not only can accurately measure temperature, but also has the characteristics of a convenient communication network, safe and reliable information, and strong insulation ability, which is suitable for large-scale promotion and application.

Research on online monitoring system of fusion transmission line based on multi-source data

With the rapid development of China’s national economy, the length of transmission lines is increasing steadily, and the operating status of high-voltage transmission lines is directly related to the operational safety and efficiency of the entire power grid, but the sensors of transmission lines can only monitor one type of fault, and the fault analysis has limitations, which makes it impossible to comprehensively judge the operating status of transmission lines. This paper designs a transmission line online monitoring system based on multi-source data fusion, which adopts the improved Kalman filter algorithm. The data collected by the front-end system is fused, analyzed and shared in real time through the edge computing fusion terminal, so as to achieve a comprehensive judgment on the operation of transmission lines and improve the safe and stable operation level of transmission lines.

The Optimal Correcting the Power Value of a Nuclear Power Plant Power Unit Reactor in the Event of Equipment Failures

The paper considers the problem of adjusting the power of a nuclear power plant power unit reactor for those cases when equipment failure occurs. In such circumstances, sometimes it is sufficient to reduce the reactor power, while maintaining the probabilistic level of safe operation of the power unit. The rational number of the reactor power is determined by solving the problem of minimizing the risk criterion in the integral root mean square context. In order to demonstrate the efficiency of the proposed approach, a numerical example is considered. The approach outlined in the paper is focused on improving the power unit control in case of equipment failures.

Development and Application of Infrared Video Intelligent Diagnosis Device for Substation Equipment Based on Edge Calculation

In recent years, infrared detection technology is widely used in the field of state detection of power equipment. It can timely and effectively find equipment defects and avoid the further development of equipment defects. However, the conventional manual inspection has some problems, such as heavy workload, long time-consuming and low efficiency. Based on the research of infrared image intelligent detection technology of substation equipment based on deep learning algorithm and digital image lossless compression technology, a set of infrared video intelligent diagnosis device of substation equipment based on edge calculation is developed and applied in practice. The device realizes local real-time rapid processing and timely diagnosis of equipment defects, and the accuracy of defect identification is about 94.44%, which greatly improves the safe and stable operation level and power supply reliability of substation equipment.

Optimized Denoising Method for Weak Acoustic Emission Signal in Partial Discharge Detection

Acoustic emission (AE) technology can predict the occurrence of partial discharge (PD) faults, which is used to improve the safe operation level of gas-insulated switchgear (GIS) equipment. However, the strong noise interference from the production site is still the main factor affecting the identification accuracy. In this study, a simplified model is designed to approximate the accumulation of free metal particles on the surface of the GIS internal insulation structure, and white noise of various intensities is added to the collected PD-induced AE signals to simulate the background interference. The results prove that the proposed denoising method can achieve a better denoising effect in various signal-to-noise ratio (SNR) conditions. In particular, in the case of low SNR, the recognition accuracy of the accumulation degree of metal particles has been improved by more than 15%.

Dynamic stability analysis of power grid in high proportion new energy access scenario based on deep learning

The “carbon peaking and carbon neutralization” scheme formulated to solve the power energy shortage makes the new energy units incorporated into the power grid on a large scale. The randomness and volatility caused by the high proportion of new energy access have a certain impact on the dynamic stability of the power grid. Based on the dynamic stability theory, this paper applies the dual-stream CNN algorithm in the deep learning technology to model, takes the power of each node and line as the input and the key eigenvalue as the output, quickly identifies the main oscillation modes of the power system, makes a qualitative evaluation. Combined with the actual power grid analysis, the interval oscillation frequencies of the system are 0.57 Hz and 0.53 Hz respectively, which belong to strongly damped oscillation and can be quickly subsided after being excited. It can be concluded that the dual-stream CNN algorithm can provide reliable technical support for subsequent dispatching operation, and is conducive to improving the safe and stable operation level of power system.

PRESERVATION OF AUTHENTICITY AND ADAPTATION OF AN OBJECT OF CULTURAL HERITAGE - COMPROMISE OR CONFLICT

The issue of carrying out repair and restoration works of the cultural heritage object of the XIX century “Building of the Noble Assembly” in Simferopol and its adaptation to a new functional purpose with the preservation of authenticity is considered. As a rule, the original purpose of the building loses its relevance, the adaptation of the object to new functions is sometimes the only way to preserve the object of cultural heritage. Such objects need an integrated approach not only in assessing the technical condition, ensuring a suffi cient level of safe operation, but also in complex microclimatic studies to ensure a comfortable future use. Adaptation of a cultural heritage site with underestimation of microclimatic parameters leads to a confl ict of authenticity and comfort. The article presents the results of a survey of the 19th century cultural heritage site “The Building of the Noble Assembly” in Simferopol with an assessment of its technical condition. Recommendations have been developed for strengthening the load-bearing structures of the building, allowing for further safe operation, while maintaining its authenticity.

Power estimation method of low-voltage distributed photovoltaic generation based on similarity aggregation

Regarding to the issue that there is no automatic data acquisition for low-voltage distributed photovoltaic generation, a power estimation method for low-voltage distributed photovoltaic generation based on similarity aggregation is proposed in this paper. Firstly, based on the time series power curve data characteristics of middle-voltage distributed photovoltaic generation and L2 norm distance, a middle-voltage distributed photovoltaic aggregation model is established, and a solution method of middle-voltage distributed photovoltaic aggregation based on K-means clustering is proposed; Secondly, based on the aggregation results of middle-voltage distributed photovoltaic, a parameter calculation method for the power estimation of low-voltage distributed photovoltaic based on geographical distribution and electricity data is proposed; Thirdly, considering the time series data characteristics of distributed photovoltaic changing with date, a strategy to determine whether to re-calculate the middle-voltage distributed photovoltaic aggregation and the power estimation parameters according to the cumulative error is proposed. Finally case studies are accomplished and the effectiveness of the proposed method are verified. The aggregation of middle-voltage distributed photovoltaic and the power estimation of low-voltage distributed photovoltaic, which is helpful to master the overall power generation of regional distributed photovoltaic, realize the observability of low-voltage distributed photovoltaic power generation, improve the safe operation level of distribution network, and has important theoretical and practical significance for serving the orderly development of distributed photovoltaic generations.

Development of Safety Star Grading Program: A Star Rating System for Express Bus Operator in Malaysia


 
 
 In 2007, the Malaysian Institute of Road Safety Research (MIROS) with engagement from numerous stakeholders has come out with a Safety, Health and Environment Code of Practice (SHE COP). The main reason for the existence of this SHE COP is because of a drastic increase in the number of crashes within the five years involving commercial vehicles especially express buses. Subsequently, in 2010, SHE COP has been gazetted as Industrial Code of Practice for Transportation Sector (ICOP 2010) under the Occupational Safety and Health Act 1994 (OSHA 1994). This ICOP 2010 can be used as guidelines to improve safety management for fleet operators. However, it has limitations to disseminate information to the public on the level of safe operation by the operators for them to make a good decision. Through some focus group discussions, a review of ICOP 2010, and a pilot test, MIROS has developed a star rating system named as Safety Star Grading Program (SSG) to provide information to the public on the level of safety management and service performance of the express bus operators. This SSG rating criteria consist of 4 elements which are safety, health, service performance, and comfort. Under the safety element, there are six sub-elements which are policy, organization, planning and implementation, evaluation, and action. Overall, this SSG was developed by referring to the basic concept of a safety management system to provide public transportation users with information to make a better decision on choosing the safest operator.
 
 

Research on Power Equipment Fault Diagnosis Technology Based on Acoustic Signal

In recent years, with the continuous growth of China’s electricity load, the power industry has developed rapidly. Power transformer is the most important and expensive in transmission and distribution system of large-scale power equipment, which undertakes the important task of power transmission. With the development of power system towards ultra-high voltage, large power grid and intelligence, it is particularly important to improve the safe operation level of transformers. Once the power transformer accident occurs, the repair time is longer and the influence is more serious. To solve this problem, a new power equipment fault diagnosis technology based on acoustic signals is studied in this paper, which is used to accurately diagnose and analyse the running state of the transformer. The simulation results show that the fault diagnosis based on acoustic signal is more accurate and can effectively diagnose the fault of power equipment.

Optimization strategy of operation and maintenance based on econometric model

With the continuous development of power grid, the investment of equipment assets is increasing sharply during the 13th Five Year Plan Period. There is a growing need for equipment maintenance as the equipment ages and varies in different types from transmission to distribution equipment. Equipment is the base element of healthy power grid development. Therefore, it is important to raise the efficiency and quality of equipment status via operation and maintenance. To improve the effectiveness of equipment maintenance, reduce the maintenance cost, improve the safe operation level and power supply reliability of power grid, this paper uses econometric model of correlation analysis to build the correlation between daily overhaul, operation and maintenance and fault frequency and voltage qualification rate, so as to provide optimal decision for the development of operation, inspection and maintenance of power grid company.

GEOPHYSICAL STUDIES AND STRENGTHENING A LAYERED AND WATER-SATURATED SOIL MASS IN THE KYIV METRO CONDITIONS

Purpose. An urgent issue for shallow underground tunnels in difficult engineering and geological conditions is the determination of the physical and mechanical properties of soils not only during engineering surveys, but also when they are studied using geophysical methods for studying ground conditions. In addition, it is important to choose ways to improve the properties of soils by strengthening, especially in areas where their strength characteristics are reduced. This ensures the efficient operation of tunnels with the elimination of hazardous phenomena such as vibration creep of soils and deformations of the track and lining. Methodology. Using the existing provisions on geophysical research, in order to identify the weaknesses of the layered and water-saturated massif and justify ways to strengthen it, the basics of a comprehensive study and production implementation have been developed to increase the level of safe operation of metro tunnels. Findings. Geophysical studies were carried out to identify weaknesses in the soil stratum along the route of the running tunnels of the Syretsko-Pechersk line of the Kyiv metro (the left bank of the Dnipro) and it was established that in present conditions, to strengthen weak water-saturated and layered soils, it is necessary to use methods of mixing soils with binders that are injected under pressure. Originality. Based on the performed analytical studies, the dependence of the porosity of weak water-saturated soils on the ratio of the acceleration of vibrations to the acceleration of gravity at certain frequencies of the path vibration caused by the movement of metro trains was obtained, and the parameters of soil strengthening on the sides and the bottom of the rim of the running tunnels were determined. Practical value. The use of geophysical methods for determining weak spots in the soil massif allowed them to be strengthened in the existing shallow underground tunnels and reduce the risk of their dangerous operation.

HAZOP_LOPA-based operation process risk analysis and management research

At present, HAZOP analysis and LOPA analysis are widely used to analyze and control the risk of process flow, but few people manage HAZOP and LOPA for risk during operation. Through the research of HAZOP and LOPA analysis methods, combined with long-term work experience in the field, the author proposes to combine HAZOP and LOPA analysis methods into operational process safety risk analysis, and use the same subject expert team to identify the risks in the operation process. Control and control results also help to re-revise the operating procedures, conduct risk management and control from the operational level, and improve the completeness of safety evaluation. This paper introduces the basic method of HAZOP_LOPA joint analysis operation process, clarifies the analysis points, and lists the commonly used 8 types of guidance words. Finally, the risk of maintenance and maintenance operation of quick-open blind filter is analyzed by examples. The results show that Based on HAZOP_LOPA, operational risk analysis can quantitatively evaluate the reliability of existing protection measures, eliminate or reduce safety risks, and achieve safety risk review of operational procedures. This method improves the reliability of operating procedures and enhances the safe operation level of employees. It is of great significance.

Study on the Unified Data of Power Regulation System for Guizhou Power Grid

The grid structure of the Guizhou Power Grid is becoming more and more complex, and the deepening of regulatory integration has made the information and work of regulators more and more onerous. Combining artificial intelligence, big data technology and grid control business is an inevitable trend of development. In this paper, a unified data model of the power system is established based on the Guizhou power grid’s regulatory operation requirements. It can analyze the impact of big data on dispatching business and define the power business demand model in the big data environment. This model also integrates and manages the multi-source heterogeneous data of power grid business by reflecting data and relationships of power regulation business. The research results are of great significance to improve the level of safe and stable operation of the power grid, and to promote intelligent operation of regulation and control, and also lay a solid foundation for intelligent dispatch.