A Discussion on recent advances in heavy electrical plant - A review of the development of the vacuum interrupter

1973 ◽  
Vol 275 (1248) ◽  
pp. 121-129 ◽  
Keyword(s):  
Power Systems ◽  
Future Development ◽  
Reasonable Agreement ◽  
Theory And Practice ◽  
High Current ◽  
Physical Processes ◽  
Vacuum Interrupter ◽  
Advantages And Disadvantages ◽  
Recent Advances ◽  
Properties Of Materials

The basic physical processes occurring in vacuum arcs are described, and it is shown that reasonable agreement exists between theory and practice as to the interrupting ability to be expected of vacuum interrupters. Designs of interrupters and contacts for both low and high current applications are reviewed, together with the properties of materials required. The advantages and disadvantages of this method of circuit interruption in power systems are discussed, together with the present applications of these interrupters. Finally, an attempt is made to predict the pattern of future development of interrupters and of their applications.

POWER SHELL ELEMENTS: DYNAMIC MATHEMATICAL MODELS, POWER SYSTEMS (OVERVIEW)

2021 ◽  
pp. 31-39
Author(s):  
Pavel P. Chernus ◽  
A. K. Arbiev ◽  
Petr P. Chernus ◽  
P. A. Loshitskiy ◽  
V. T. Sharovatov
Keyword(s):  
Power Systems ◽  
Mathematical Models ◽  
Gas Flow ◽  
Transfer Functions ◽  
Theory And Practice ◽  
Design Stage ◽  
Shell Elements ◽  
Advantages And Disadvantages ◽  
Working Medium ◽  
Compressed Gas

This article is a review devoted to the theory and practice of the application of power shell elements (PSE) in pneumatic drives (PD). She makes acquaint the reader with the main provisions of the theory of PD, performed on the PSE. The review briefly presents materials on the development of dynamic mathematical models (DMM) of power units (PU) of shell PDs (SPD), based on the use of static characteristics of SPD, an assessment of the advantages and disadvantages of PU based on traditional pneumatic cylinders (PC) and PSE is given. The main attention in the review is paid to the solution of the problem of creating PU on PSE with the required quality indicators at the design stage, when it is necessary to take into account the properties of compressed gas. For this, an original methodology for the development of nonlinear DMMs for various typical variants of the midrange is proposed, the basis of which is a number of provisions of the theory of gas dynamics. Without invoking this theory, it is impossible to ta into account the properties of compressed gas (compressibility of the working medium, dependence on temperature and gas flow rate in the shell, the nature of the gas expansion processes), and, therefore, to reliably describe the state of unsteady gas processes inside the shell and develop a DMM of the PU, to a sufficient taking into account the mentioned properties. Since the topic of this review is intended mainly for engineers who develop SPD (theoreticians and practitioners), the review also contains materials on the linearization of the found nonlinear DMMs. As a result of linearization, nonlinear DMMs are transformed into transfer functions for displacement of the output coordinate and effort. The correctness of the linearization carried out is confirmed by the results of experiments. The review briefly discusses several options for pneumatic supply systems for SPD. Here, of particular interest for a specialist is the material on imparting invariance properties to SPDs to air intake from the atmosphere nd discharge of exhaust air into the atmosphere, which significantly expands the scope of SPDs and reduce their cost.

POWER SHELL ELEMENTS: DYNAMIC MATHEMATICAL MODELS, POWER SYSTEMS (OVERVIEW) Continuation

2021 ◽  
pp. 36-43
Author(s):  
Pavel P. Chernus ◽  
A. K. Arbiev ◽  
Petr P. Chernus ◽  
P. A. Loshitskiy ◽  
V. T. Sharovatov
Keyword(s):  
Power Systems ◽  
Mathematical Models ◽  
Gas Flow ◽  
Transfer Functions ◽  
Theory And Practice ◽  
Design Stage ◽  
Shell Elements ◽  
Advantages And Disadvantages ◽  
Working Medium ◽  
Compressed Gas

This article is a review devoted to the theory and practice of the application of power shell elements (PSE) in pneumatic drives (PD). She makes acquaint the reader with the main provisions of the theory of PD, performed on the PSE. The review briefly presents materials on the development of dynamic mathematical models (DMM) of power units (PU) of shell PDs (SPD), based on the use of static characteristics of SPD, an assessment of the advantages and disadvantages of PU based on traditional pneumatic cylinders (PC) and PSE is given. The main attention in the review is paid to the solution of the problem of creating PU on PSE with the required quality indicators at the design stage, when it is necessary to take into account the properties of compressed gas. For this, an original methodology for the development of nonlinear DMMs for various typical variants of the midrange is proposed, the basis of which is a number of provisions of the theory of gas dynamics. Without invoking this theory, it is impossible to take into account the properties of compressed gas (compressibility of the working medium, dependence on temperature and gas flow rate in the shell, the nature of the gas expansion processes), and, therefore, to reliably describe the state of unsteady gas processes inside the shell and develop a DMM of the PU, to a sufficient taking into account the mentioned properties. Since the topic of this review is intended mainly for engineers who develop SPD (theoreticians and practitioners), the review also contains materials on the linearization of the found nonlinear DMMs. As a result of linearization, nonlinear DMMs are transformed into transfer functions for displacement of the output coordinate and effort. The correctness of the linearization carried out is confirmed by the results of experiments. The review briefly discusses several options for pneumatic supply systems for SPD. Here, of particular interest for a specialist is the material on imparting invariance properties to SPDs to air intake from the atmosphere and discharge of exhaust air into the atmosphere, which significantly expands the scope of SPDs and reduce their cost.

Recent Advances in Reinforcement Learning for Traffic Signal Control

2021 ◽  
Vol 22 (2) ◽  
pp. 12-18 ◽  
Author(s):  
Hua Wei ◽  
Guanjie Zheng ◽  
Vikash Gayah ◽  
Zhenhui Li
Keyword(s):  
Reinforcement Learning ◽  
Real World ◽  
Intelligent Transportation Systems ◽  
Transportation Systems ◽  
Traffic Signal ◽  
Signal Control ◽  
Traffic Signal Control ◽  
Control Methods ◽  
Advantages And Disadvantages ◽  
Recent Advances

Traffic signal control is an important and challenging real-world problem that has recently received a large amount of interest from both transportation and computer science communities. In this survey, we focus on investigating the recent advances in using reinforcement learning (RL) techniques to solve the traffic signal control problem. We classify the known approaches based on the RL techniques they use and provide a review of existing models with analysis on their advantages and disadvantages. Moreover, we give an overview of the simulation environments and experimental settings that have been developed to evaluate the traffic signal control methods. Finally, we explore future directions in the area of RLbased traffic signal control methods. We hope this survey could provide insights to researchers dealing with real-world applications in intelligent transportation systems

scholarly journals A Review of Techniques for RSS-Based Radiometric Partial Discharge Localization

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 909
Author(s):  
David W. Upton ◽  
Keyur K. Mistry ◽  
Peter J. Mather ◽  
Zaharias D. Zaharis ◽  
Robert C. Atkinson ◽  
...  
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Partial Discharge ◽  
Specific Area ◽  
Electrical Insulation ◽  
Acoustic Detection ◽  
Advantages And Disadvantages ◽  
Initial Stage ◽  
Catastrophic Failures ◽  
Radiometric Detection

The lifespan assessment and maintenance planning of high-voltage power systems requires condition monitoring of all the operational equipment in a specific area. Electrical insulation of electrical apparatuses is prone to failure due to high electrical stresses, and thus it is a critical aspect that needs to be monitored. The ageing process of the electrical insulation in high voltage equipment may accelerate due to the occurrence of partial discharge (PD) that may in turn lead to catastrophic failures if the related defects are left untreated at an initial stage. Therefore, there is a requirement to monitor the PD levels so that an unexpected breakdown of high-voltage equipment is avoided. There are several ways of detecting PD, such as acoustic detection, optical detection, chemical detection, and radiometric detection. This paper focuses on reviewing techniques based on radiometric detection of PD, and more specifically, using received signal strength (RSS) for the localization of faults. This paper explores the advantages and disadvantages of radiometric techniques and presents an overview of a radiometric PD detection technique that uses a transistor reset integrator (TRI)-based wireless sensor network (WSN).

Integrating molecular and morphological approaches for characterizing parasite cryptic species: implications for parasitology

Parasitology ◽  
2011 ◽  
Vol 138 (13) ◽  
pp. 1688-1709 ◽  
Author(s):  
STEVEN A. NADLER ◽  
GERARDO PÉREZ-PONCE DE LEÓN
Keyword(s):  
Cryptic Species ◽  
Applied Research ◽  
Molecular Data ◽  
Theory And Practice ◽  
Parasitic Diseases ◽  
Advantages And Disadvantages ◽  
Research Programmes ◽  
Parasite Biodiversity ◽  
Operational Practices ◽  
Methodological Considerations

SUMMARYHerein we review theoretical and methodological considerations important for finding and delimiting cryptic species of parasites (species that are difficult to recognize using traditional systematic methods). Applications of molecular data in empirical investigations of cryptic species are discussed from an historical perspective, and we evaluate advantages and disadvantages of approaches that have been used to date. Developments concerning the theory and practice of species delimitation are emphasized because theory is critical to interpretation of data. The advantages and disadvantages of different molecular methodologies, including the number and kind of loci, are discussed relative to tree-based approaches for detecting and delimiting cryptic species. We conclude by discussing some implications that cryptic species have for research programmes in parasitology, emphasizing that careful attention to the theory and operational practices involved in finding, delimiting, and describing new species (including cryptic species) is essential, not only for fully characterizing parasite biodiversity and broader aspects of comparative biology such as systematics, evolution, ecology and biogeography, but to applied research efforts that strive to improve development and understanding of epidemiology, diagnostics, control and potential eradication of parasitic diseases.

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