Operation analysis of cap and pin suspension ceramic insulators with composite shed for DC transmission lines in China

2021 ◽  
Author(s):  
Y. Chao ◽  
L. Zhang
Keyword(s):  
Transmission Lines ◽  
Operation Analysis ◽  
Ceramic Insulators

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 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.

RTV silicone rubber pre-coated ceramic insulators for transmission lines

2013 ◽  
Vol 20 (1) ◽  
pp. 237-244 ◽  
Author(s):  
E. A. Cherney ◽  
A. El-Hag ◽  
S. Li ◽  
R. S. Gorur ◽  
L. Meyer ◽  
...  
Keyword(s):  
Transmission Lines ◽  
Silicone Rubber ◽  
Ceramic Insulators ◽  
Rtv Silicone Rubber

scholarly journals Comparative study on field collected samples of aged silicon rubber composite coatings for high voltage insulators

2013 ◽  
Vol 21 (2) ◽  
pp. 93-106
Author(s):  
I.V. Tudose ◽  
M. Suchea ◽  
K. Siderakis ◽  
E. Thalassinakis ◽  
E. Koudoumas
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Silicone Rubber ◽  
Large Scale ◽  
Composite Coatings ◽  
Morphological Characterization ◽  
Primary Concern ◽  
Electrical Networks ◽  
Material Formulation ◽  
Ceramic Insulators

Abstract : Pollution of high voltage (HV) insulators is a phenomenon with a considerable impact to the performance of transmission and distribution electrical networks. The use of composite materials and especially Silicone Rubber proved to be an efficient improvement, capable of suppressing the problem and diminishing the flashover probability. As a result ceramic insulators in transmission lines are replaced by insulators with composite housing, either HTV Silicone Rubber or LSR. In the case of HV substations however, the replacement of insulators is rather difficult, due to the complexity of the equipment and the corresponding financial cost. In this case the application of RTV Silicone Rubber is an equivalent alternative. The ceramic insulators are covered with a 0.5 mm RTV SIR coating which provides the advantages of composite insulators on a ceramic substrate. After installation the possible material lifetime, which is determined by the service conditions and the material formulation, is of primary concern. In Crete, a large scale application exists and coatings that exceed a service period of 10 years are still in operation. The present study focuses on the structural and morphological characterization of field collected composite insulators of various ages so that the degradation degree can be correlated with their service.

Composite right/left-handed transmission line with array of thermocouples for generating terahertz radiation

2020 ◽  
Vol 92 (2) ◽  
pp. 20502
Author(s):  
Behrokh Beiranvand ◽  
Alexander S. Sobolev ◽  
Anton V. Kudryashov
Keyword(s):  
Transmission Line ◽  
Terahertz Radiation ◽  
Transmission Lines ◽  
Software Package ◽  
Optical Pulses ◽  
Capacitively Coupled ◽  
Voltage Difference ◽  
Left Handed ◽  
Microwave Transmission ◽  
Commercial Software Package

We present a new concept of the thermoelectric structure that generates microwave and terahertz signals when illuminated by femtosecond optical pulses. The structure consists of a series array of capacitively coupled thermocouples. The array acts as a hybrid type microwave transmission line with anomalous dispersion and phase velocity higher than the velocity of light. This allows for adding up the responces from all the thermocouples in phase. The array is easily integrable with microstrip transmission lines. Dispersion curves obtained from both the lumped network scheme and numerical simulations are presented. The connection of the thermocouples is a composite right/left-handed transmission line, which can receive terahertz radiation from the transmission line ports. The radiation of the photon to the surface of the thermocouple structure causes a voltage difference with the bandwidth of terahertz. We examined a lossy composite right/left-handed transmission line to extract the circuit elements. The calculated properties of the design are extracted by employing commercial software package CST STUDIO SUITE.

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