High voltage dc V-T characteristics of long air gaps

1983 ◽  
Vol 103 (4) ◽  
pp. 1-8
Author(s):  
Yoshinori Aihara ◽  
Takeshi Takahashi
Keyword(s):  
High Voltage ◽  
Air Gaps

Effect of the rise rate of nanosecond high-voltage pulses on the breakdown of air gaps

1999 ◽  
Vol 25 (9) ◽  
pp. 749-751 ◽  
Author(s):  
L. M. Vasilyak ◽  
S. P. Vetchinin ◽  
D. N. Polyakov
Keyword(s):  
High Voltage ◽  
Air Gaps ◽  
Rise Rate ◽  
Voltage Pulses

THE IMPROVEMENT OF THE HIGH VOLTAGE TESTING METHOD

2019 ◽  
pp. 4-14
Author(s):  
V. A. Syasko ◽  
S. S. Golubev ◽  
A. S. Musikhin
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Homogeneous Field ◽  
Inhomogeneous Field ◽  
Minimum Thickness ◽  
Air Gaps ◽  
Testing Method ◽  
Almost All

The high voltage spark testing method of protective dielectric coatings is applied in almost all manufacture areas and is governed by ISO, ASTM etc. However, all of it doesn’t pay proper attention to high voltage forming (DC or AC) and its polarity relative to electrode, influence of environment and electric field inhomogeneity. In that paper a detailed analysis of air gap breakdown forming processes was given. A dependence of electric field strength on an interelectrode gap length was given for homogeneous and highly inhomogeneous electric fields. It was shown a breakdown voltage of air gaps in highly inhomogeneous field is greatly less than in homogeneous field. Also, it is described the breakdown voltage of air gaps with positive polarity is less then with negative polarity. The possibility coatings testing with a minimum thickness up to 50 m while reducing the testing voltage without reducing the reliability of the results is shown.

scholarly journals Finite Element Modeling of Shunt Reactors Used in High Voltage Power Systems

2021 ◽  
Vol 11 (4) ◽  
pp. 7411-7416
Author(s):  
T. P. Minh ◽  
H. B. Duc ◽  
N. P. Hoai ◽  
T. T. Cong ◽  
M. B. Cong ◽  
...  
Keyword(s):  
Finite Element ◽  
Power Systems ◽  
High Voltage ◽  
Reactive Power ◽  
Magnetic Circuit ◽  
Iron Core ◽  
Air Gaps ◽  
Extra High Voltage ◽  
Shunt Reactors ◽  
Copper Losses

Shunt reactors are important components for high-voltage and extra high voltage transmission systems with large line lengths. They are used to absorb excess reactive power generated by capacitive power on the lines when no-load or under-load occurs. In addition, they play an important role in balancing the reactive power on the system, avoiding overvoltage at the end of the lines, and maintaining voltage stability at the specified level. In this paper, an analytical method based on the theory of magnetic circuit model is used to compute the electromagnetic fields of shunt reactors and then a finite element method is applied to simulate magnetic field distributions, joule power losses, and copper losses in the magnetic circuit. In order to reduce magnetic flux and avoid magnetic circuit saturation, it is necessary to increase the reluctance of the magnetic circuit by adding air gaps in the iron core. The air gaps are arranged along the iron core to decrease the influence of flux fringing around the air gap on shunt reactors' total loss. Non-magnetic materials are often used at the air gaps to separate the iron cores. The ANSYS Electronics Desktop V19.R1 is used as a computation and simulation tool in this paper.

scholarly journals Breakdown in air gaps with solid insulating barrier under impulse voltage stress

2005 ◽  
Vol 18 (1) ◽  
pp. 87-104 ◽  
Author(s):  
Frangiskos Topalis ◽  
Michael Danikas
Keyword(s):  
High Voltage ◽  
Theoretical Models ◽  
Experimental Investigations ◽  
Barrier Effect ◽  
High Voltage Electrode ◽  
Insulating Materials ◽  
Air Gaps ◽  
Voltage Stress ◽  
Theoretical Analyses

The influence of solid insulating barriers to the impulse strength of air gaps has been investigated by few researchers. It is well known that thin insulating materials increase considerably the breakdown voltage, sometimes two to three times. Some researchers performed thorough investigations for the determination of the parameters of the barrier effect that influence the impulse level for the breakdown. The distance of the barrier from the high voltage electrode is the most important parameter. The field distribution is also important as well as the shape of the insulating sheet. The experimental investigations led to some theoretical models for the breakdown process. This paper analyzes and discusses those models and spots the points where they agree as well as the differences between them. Finally, it attempts to compose a model that sheds light on the barrier effect and complies with all the experimental and theoretical analyses.

A Discussion on recent advances in heavy electrical plant - Switching surges and air insulation

1973 ◽  
Vol 275 (1248) ◽  
pp. 165-180 ◽  
Keyword(s):  
Power Systems ◽  
High Voltage ◽  
Theoretical Approach ◽  
Applied Voltage ◽  
Laboratory Testing ◽  
Power Transmission ◽  
Air Gaps ◽  
Qualitative Understanding ◽  
Prediction And Control ◽  
And Control

Some thirteen years ago, a reduction was noticed in the strength of air insulation when subjected to slowly rising positive impulse voltages such as occur during switching operatons on power systems. Methods for the prediction and control of switching overvoltages have been established and empirical data collected in high voltage laboratories. Insulation against switching surges is now seen as an important factor in the feasibility of power transmission at ultra-high voltages. The strength of large air gaps depends not only on the geometry of the gap (point-plane, rod-rod, etc.), but also on the waveshape of the applied voltage. The practical diversity of gaps and waveshapes is such that a sound theoretical approach must be found if laboratory testing is to be kept within bounds. Qualitative understanding of the breakdown processes in long air-gaps has advanced rapidly in the last two years. Predictive mathematical models are now being constructed.

scholarly journals The profile of the electric field on the earth discontinuity with a lightning conductor

2016 ◽  
Vol 1 (1) ◽  
pp. 30
Author(s):  
Ali Khechekhouche
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Field Intensity ◽  
High Voltage ◽  
Electric Field Distribution ◽  
Geometrical Model ◽  
Electrical Strength ◽  
Capture Effect ◽  
Air Gaps ◽  
The Earth

In this paper, we present some results of investigations carried out in the electric field distribution of both horizontal and vertical lightning conductors in the case of discontinuous earth. The conductors may be situated as well as in the upper or the lower earth part. The electric field distribution was determined in the case of lightning conductor situated between the high voltage rod and the discontinuity (interface) and also in the case of high voltage rod situated between the lightning conductor and the discontinuity. In some situations the electric field distribution on the plan are smaller than defined by the electro-geometrical model. We attribute this result to the great field intensity at the discontinuity, which reduce the lightning conductor discharge capture effect. This is in concordance with the results concerning the electrical strength of such air gaps without lightning conductors. 

Study on Relationships between High-Frequency High-Voltage Pulse Breakdown Voltage of Air-Gaps and Pulse Delay Time

2014 ◽  
Vol 981 ◽  
pp. 683-687
Author(s):  
Li Li Li ◽  
Yu Long Wang ◽  
Hong Da Yang
Keyword(s):  
Breakdown Voltage ◽  
High Voltage ◽  
Delay Time ◽  
High Frequency ◽  
Voltage Pulse ◽  
High Voltage Pulse ◽  
Pulse Delay ◽  
Pulse Breakdown ◽  
Air Gaps ◽  
Power Frequency

In the paper, power frequency and high-frequency high-voltage pulse breakdown voltage of air-gaps were measured by circuits of spark gap switches respectively, and then output waveforms were obtained by sampling circuits, finally a large number of data in experiments were recorded and were drawn into curves. It can be seen from curves: firstly, relationships between pulse breakdown voltage of air-gaps and pulse delay time or between pulse breakdown voltage of air-gaps and pulse coefficient are discussed when electrodes and distances between electrodes are different, secondly, relationships between pulse breakdown voltage and air-gap distances are analyzed under 100kHz pulse voltage when electrodes are spherical electrodes.

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