scholarly journals Investigation of an Insulator Flashunder in an 150 kV OTL of the Power System of Crete

2019 ◽  
Vol 9 (5) ◽  
pp. 4851-4858
Author(s):  
D. Pylarinos ◽  
I. Pellas
Keyword(s):  
Power Systems ◽  
Transmission Lines ◽  
Low Weight ◽  
Brittle Fractures ◽  
Flow Through ◽  
Core Rod ◽  
Ceramic Insulators ◽  
Phase Conductors ◽  
And Coping ◽  
First Time

Overhead Transmission Lines (OTLs) are used in Power Systems to carry High Voltage between substations, usually over long distances. Faults in OTLs are bound to happen and thus locating and coping with them is an important aspect of OTL’s operation and maintenance. These faults may be of temporary or permanent nature, with certain types of faults progressing over time from the first category to the second. Local weather may also have a direct effect on the occurrence of faults resulting to puzzling events. A special category, often complex in nature, is insulator faults. Insulators are used in OTLs to support phase conductors while not allowing current to flow through the tower’s body to the ground. Traditional ceramic insulators used materials such as porcelain and glass as insulation, but in the last decades composite insulators with two insulating parts (a glass core/rod and a rubber housing), have also known great use mainly due to their low weight and their capability to withstand pollution. However, they are subjected to certain faults unique to them, such as flashunders. Flashunder is a term commonly used lately to describe faults that are related to the rod/housing interface of composite insulators. Such faults are rather difficult to locate as the electrical discharge does not create an easily visible trace (as in the case of flashovers) or a permanent mechanical fault (as in the case of brittle fractures). Such a fault occurred for the first time in the Transmission System of Crete in 2019 and this paper follows and discusses the incident and the experience gained.

scholarly journals Global experience of HVDC composite insulators in outdoor and indoor environment

2020 ◽  
Vol 59 (1) ◽  
pp. 606-618
Author(s):  
Mohammad Akbar ◽  
Basharat Mehmood
Keyword(s):  
High Voltage ◽  
Direct Current ◽  
Transmission Lines ◽  
Power Transmission ◽  
Green Energy ◽  
Attractive Alternative ◽  
Hvdc Transmission ◽  
Ceramic Insulators ◽  
High Power Transmission ◽  
Aging Performance

AbstractHigh-voltage direct current (HVDC) transmission is known as green-energy transfer technology and has recently become an attractive alternative of high-voltage alternating current (HVAC) due to its high-power transmission capability and lower power loss. Use of composite insulators on direct current (DC) transmission lines experienced rapid growth in recent years due to their high hydrophobicity and better performance in contaminated environment than conventional ceramic insulators. During their service operation on DC lines, insulators are prone to more accumulation of contaminants due to unidirectional electric field. The contaminants under wet conditions allow leakage current to flow on the insulator surface. Being organic in nature, polymeric insulators have a tendency to age under the combined effects of electrical and environmental stresses. To fully understand the long-term aging performance of DC composite insulators, a detailed survey was considered necessary. Towards that end, this paper critically summarizes worldwide experience of aging performance of composite insulators in the field as well as in laboratory conditions.

scholarly journals A Method for Autonomous Navigation and Positioning of UAV Based on Electric Field Array Detection

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1146 ◽  
Author(s):  
Yincheng Li ◽  
Wenbin Zhang ◽  
Peng Li ◽  
Youhuan Ning ◽  
Chunguang Suo
Keyword(s):  
Mathematical Model ◽  
Power Systems ◽  
Transmission Lines ◽  
Autonomous Navigation ◽  
Strength Distribution ◽  
Field Source ◽  
Navigation Algorithm ◽  
Safety Warning ◽  
Positioning Algorithm ◽  
Navigation Equipment

At present, the method of using unmanned aerial vehicles (UAVs) with traditional navigation equipment for inspection of overhead transmission lines has the limitations of expensive sensors, difficult data processing, and vulnerable to weather and environmental factors, which cannot ensure the safety of UAV and power systems. Therefore, this paper establishes a mathematical model of spatial distribution of transmission lines to study the field strength distribution information around transmission lines. Based on this, research the navigation and positioning algorithm. The data collected by the positioning system are input into the mathematical model to complete the identification, positioning, and safety distance diagnosis of the field source. The detected data and processing results can provide reference for UAV obstacle avoidance navigation and safety warning. The experimental results show that the positioning effect of the positioning navigation algorithm is obvious, and the positioning error is within the range of use error and has good usability and application value.

Assessment of technical condition of high-voltage overhead power transmission lines at the stage of their ageing

2021 ◽  
Vol 14 (2) ◽  
pp. 100-107
Author(s):  
E. M. Farhadzadeh ◽  
A. Z. Muradalyiev ◽  
S. A. Muradalyiev ◽  
A. A. Nazarov
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Transmission ◽  
Operational Reliability ◽  
Technical Condition ◽  
Weak Links ◽  
Power Transmission Lines ◽  
Nonlinear Growth ◽  
Overhead Power Transmission Lines

The organization of operation, maintenance and repair of the basic technological facilities of electric power systems (EPS), which are beyond their designed service life (hereinafter referred to as ageing facilities, or AFs) is one of the problems that determine the energy security of many countries, including economically developed nations. The principal cause of insufficient overall performance of AFs is the traditional focus of the EPS management on economic efficiency and the insufficient attention to reliability and safety of AFs. The tendency to nonlinear growth in the frequency of occurrence of unacceptable consequences in the EPS requires ensuring the operational reliability and safety of AFs. The averaged estimates of reliability and safety used at designing power facilities are not suitable for characterization of overall operational performance. Among the basic and the least investigated (in terms of operational reliability and safety) EPS facilities are overhead power transmission lines (OPL) with a voltage of 110 кV and above. This is for a reason. OPL are electric power facilities with elements distributed along a multi-kilometer line (supports, insulators, wires, accessories, etc.). That is what makes the organization of continuous monitoring of the technical condition of each of these elements, and, consequently, the assessment of operational reliability and safety, so problematic. A method is suggested for assessment of “weak links” among the operated OPL on operative intervals of time along with a method for assessment of the technical condition of OPL at examination of a representative sample.

Electron Flow through Geometrical Discontinuity in Coaxial Magnetically Insulated Transmission Lines

2000 ◽  
Vol 39 (Part 1, No. 9A) ◽  
pp. 5280-5286 ◽  
Author(s):  
Kazuki Hiraoka ◽  
Mitsuo Nakajima ◽  
Makoto Shiho ◽  
Kazuhiko Horioka
Keyword(s):  
Transmission Lines ◽  
Electron Flow ◽  
Flow Through ◽  
Geometrical Discontinuity

scholarly journals Research on High-strength Flexible Insulation Rod of Ultra High Voltage Live Working

2021 ◽  
Vol 248 ◽  
pp. 01054
Author(s):  
Zhigang Wang ◽  
Yun Xiang ◽  
Ziqi Yi ◽  
Longfei He ◽  
Mingjie Chen ◽  
...  
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Large Deflection ◽  
High Strength ◽  
Heavy Weight ◽  
Existing Problems ◽  
The Core ◽  
New Type ◽  
Protective Cover ◽  
Core Rod

Insulation pull rods are commonly used tools and instruments in the replacement of insulators for live work. Traditional hard insulated pull rods are difficult to transport and assemble due to their large deflection, especially due to the long and heavy weight of insulated pull rods used in UHV live operations, the difficulties in the above links are more obvious. In view of the existing problems in the use of the existing insulated pull rods, by studying the overall processing type, the soft pull rod weaving process, the technology of tightly combining the core rod and the protective cover, the technology of connecting the core rod and the metal, etc., a new type suitable for live transmission lines has been developed. Large-tonnage soft insulated pull rod for operation. Effectively solve a series of problems caused by the large deflection of the hard insulated pull rod.

scholarly journals Electric Field Analysis of High Voltage Insulators

2012 ◽  
pp. 59-63
Author(s):  
Rahul Krishnan ◽  
Subhajit Samanta ◽  
Sudha R ◽  
K Govardhan
Keyword(s):  
Electric Field ◽  
Power Systems ◽  
Transmission Lines ◽  
Field Analysis ◽  
Voltage Profile ◽  
Element Analysis ◽  
Body Angle ◽  
Long Rod ◽  
Multiple Materials ◽  
Electric Field Analysis

This paper involves designing and applying electric field analysis on multiple long rod insulators. Quality HV insulators are an integral part of power systems because they separate the Transmission lines carrying high voltages from the grounded poles. They must have the ability to withstand both high electrical and mechanical stress. So for this purpose modeling of long rod insulator was done with multiple materials such as ceramic, porcelain, and fiber glass and silicon rubber. Electric field analysis can be used to determine voltage profile of each material which in turn can be used to determine how much electrical stress the material can undertake. An attempt was made to model existing long rod insulator designs using software like Solidworks. Subsequently modifications were made to the design by changing parameters such as diameter of the insulator body, angle made by insulator cups etc. These models were then subjected to electric field analysis using finite element analysis software such as Elecnet or Comsol Multiphysics in order to identify the points where maximum electric field stress exists. Further modifications were made on order to reduce and equalize the electric field over the insulator surface.

Relay protection and automation of electric power systems

2021 ◽  
Author(s):  
Sergey Goremykin
Keyword(s):  
Power Systems ◽  
Electric Power ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Transmission ◽  
Relay Protection ◽  
Electrical Equipment ◽  
Electric Power Systems ◽  
Federal State ◽  
Advantages And Disadvantages

The textbook describes the main issues of the theory of relay protection and automation of electric power systems. The structure and functional purpose of protection devices and automation of power transmission lines of various configurations, synchronous generators, power transformers, electric motors and individual electrical installations are considered. For each of the types of protection of the above objects, the structure, the principle of operation, the order of selection of settings are given, the advantages and disadvantages are evaluated, indicating the scope of application. The manual includes material on complete devices based on semiconductor and microprocessor element bases. The progressive use of such devices (protection of the third and fourth generations) is appropriate and effective due to their significant advantages. Meets the requirements of the federal state educational standards of higher education of the latest generation. It is intended for students in the areas of training 13.03.02 "Electric power and electrical engineering" (profile "Power supply", discipline "Relay protection and automation of electric power systems") and 35.03.06 "Agroengineering" (profile "Power supply and electrical equipment of agricultural enterprises", discipline "Relay protection of electrical equipment of agricultural objects"), as well as for graduate students and specialists engaged in the field of electrification and automation of industrial and agrotechnical objects.

Analysis of mathematical models of transmission lines.

2020 ◽  
Vol 23 (2) ◽  
pp. 16-19
Author(s):  
G. SHEINA ◽  
Keyword(s):  
Mathematical Model ◽  
Power Systems ◽  
Transmission Lines ◽  
Power Supply ◽  
Power Supply System ◽  
Power Transmission ◽  
Supply System ◽  
Power Lines ◽  
Power Transmission Lines ◽  
The Mathematical Model

This paper investigates a mathematical model of one elements of the power supply system - power transmission lines. The type of models depends on the initial simplifications, which in turn are determined by the complexity of the physics of processes. The task of improving the accuracy of modeling of emergency processes in the power system is due to the significant complexity of modern power systems and their equipment, high-speed relay protection, automation of emergency management and the introduction of higher-speed switching equipment. One of the reasons for a significant number of serious emergencies in the system is the lack of complete and reliable information for modeling modes in the design and operation of power systems. The development of a mathematical model of a three-phase power line, which provides adequate reflection of both normal and emergency processes, is relevant. The advanced mathematical model of power transmission lines allows to investigate various operational modes of electric networks. The improved mathematical model of the power transmission line reflects all the features of physical processes at state modes and transient process and provides sufficient accuracy of the results. The type of mathematical model of power transmission lines depends on the accepted simplifications, depending on the task of research. The purpose of this work is to analyze the mathematical model of the power transmission line to study the modes of operation of the power supply system, with the possibility of its application to take into account all the design features of overhead and cable power lines. The mathematical model of the power line for the study of the modes of operation of the power supply system is analyzed. It is used to take into account the design features of overhead and cable power lines, skin effect.

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