A newly devised electric field screen for avoidance and capture of cigarette beetles and vinegar flies
Yoshinori MatsudaTeruo NonomuraKoji KakutaniYoshihiro TakikawaJunji KimbaraYoshihiro KasaishiKazumi OsamuraShin-ichi KusakariHideyoshi Toyoda
39
Citation
25
Reference
10
Related Paper
Citation Trend
Keywords:
Lasioderma serricorne
In this paper impact of the tower arrangements on the mitigation of the increased values of the electric field intensity at high-voltage transmission line conductors was investigated. Several configurations of high-voltage towers (horizontal, delta, reverse delta, vertical and split-phase configurations) were analyzed. It assumed that the same height of the lowest phase conductors above the ground and the same value of the connected 400 kV voltage. The calculations were carried out for the values of the electric field intensity on the surface of the conductor and its immediate vicinity. A charge simulation method was used to calculate the electric field intensity on the surface of the stranded conductors and their immediate vicinity.
Intensity
Transmission tower
Cite
Citations (0)
The evaluation of the lightning shielding failure of a transmission line is very important in power transmission system design, and the operation voltage has rarely been considered before. However, when the operation voltage reaches 800 kV and the tower height is near 100 m, the influence of operation voltage may not be ignored. In this paper, an experimental system consisting of an air gap between a plate/rod and a conductor was established, where the dc voltage could be applied to the conductor and was accompanied by a negative impulse voltage on the plate/rod electrode. An upward leader up to 1.54 m in length was observed, and the leader velocity and charge density were obtained in a 11-m-long air gap, whereas the voltage on the conductor was 800-kV dc. The influence of dc operation voltages on the upward leader was studied. The experimental results showed that the upward leader will emerge much earlier and may progress longer with dc operation voltages. That is, the lightning attachment to the conductor may occur more easily when the voltage of the conductor is opposite in polarity to that of the downward lightning than when the conductor has no operation voltage.
Air gap (plumbing)
Polarity symbols
Cite
Citations (22)
The pieces of insulator under power frequency voltage are calculated and corrected through leakage distance ratio based on pollution class of transmission line at high altitude area,then the pieces are checked under the conditions of operating over-voltage and lightning over-voltage,finally the pieces of insulator are determined by comparisons of the pieces under power frequency voltage,operating over-voltage and lightning over-voltage.
High Voltage
Cite
Citations (0)
The insulation strengths for line and station insulators tested with various switching surges in the presence of dc voltage bias are described. This is part of a larger research effort to pinpoint technical problem areas in overhead line design and operation at voltages of +-600 kV to +-1200 kV. The results reported can be used to determine conductor-to-tower clearances, length of the insulator column supporting a station bus, and clearances between buses. In testing station buses it was observed that the presence of the second bus, which is connected to ground or is under a negative bias voltage, affects the level of voltage needed to produce a breakdown across the insulator column supporting the first bus. Bus height above ground also affects the breakdown voltage across the insulator column and between buses. In order to assure that all bus-to-ground breakdowns terminate on the lower part of the insulator column and not to the ground plane, a proper coordination between insulator column length and bus height above ground should be maintained. Because of the many parameters affecting the breakdown voltage of air gaps, and the preliminary nature of this research investigation, the results obtained should be considered ''typical'' and should not be used for final specification of air insulating clearances. When testing with mixed voltages, the breakdown voltage decreased for the conductor-to-tower arrangement as the impulse component was increased. On the other hand, the flashover voltage increased for the bus-to-bus arrangement with an increasing impulse component. These apparent inconsistencies were not expected from the limited amount of existing data. No reasonable explanation was developed. Power supply requirements for dc insulator contamination tests have also been investigated. Separate reports contain the results of this work.
Arc flash
Overvoltage
Ground plane
High Voltage
Overhead line
Cite
Citations (0)
High Voltage
Cite
Citations (15)
Abstract In recent years, the ablation damage of overhead insulated conductor on the top of insulators has posed a threat to the safe and stable operation of distribution network. In this paper, a three-dimensional model including insulator, binding wire and conductor is established in the finite element simulation. Then analyse the influence of the existence of binding wire and the diameter of binding wire on the electric field distribution of conductor. Providing a theoretical basis for the cause and prevention of the ablation damage of conductor insulation layer. The simulation results are as follows: When binding wire exists, electric field distortion will occur in the insulation layer and surface air around the conductor. The maximum electric field intensity of the surface air around conductor reaches 15.5kV/cm, which is about 690% higher than that without a binding wire. The maximum electric field intensity of the insulation layer reaches 4.3kV/cm, which is 980% higher than that without binding wire. In addition, as the diameter of the binding wire increases, the maximum electric field intensity in the insulating layer decreases and the maximum electric field intensity in the air on the surface around the conductor has small change.
Intensity
Cite
Citations (0)
The root cause of partial discharge at the overhead binding line of the distribution line is that the electric field strength increases and exceeds the initial electric field strength of the discharge, so it is important to analyze the factors affecting the change of the electric field strength. In this paper, the electric field distribution characteristics of the distribution line at the overhead binding line under normal working conditions are simulated and calculated, and the key characteristic quantities of the discharge and the possible positions of the discharge are obtained under three working conditions of the insulator under different deterioration degree, wetting degree and binding line structure. The simulation results show that the maximum electric field strength decreases from 6.72kV/cm when the conductor is intact to 4.63kV/cm with the deepening of insulator deterioration cracks; With the increase of the distance between the binding wire and the conductor, the maximum electric field strength decreases continuously, and the minimum value is 0.266kV/cm; The field strength increases with the decrease of humidity at the binding line, and the maximum value is 7.8kV/cm.
Field strength
Overhead line
Line (geometry)
Cite
Citations (0)
The authors present direct measurements of charge distributions in coaxial cables conducted during the application of a high voltage, using the pressure wave propagation (PWP) method. It is shown that, as could be expected, the main effects take place near the inner electrode, where the applied electric field is the largest. Near this electrode, charges are transferred which lead to the creation of homocharges and to a decrease of the interfacial electric field. Heterocharges build up with time and compensate the effect of the homocharges on this electric field. A stabilized state is reached at 50 degrees C after approximately 120 hours. Heterocharges of two types have been observed, some localized very close to the inner electrode, the others extending over a quarter of the insulator. The origin of the first type can be attributed to the diffusion in the insulator of impurities present in the inner semiconducting electrode impurities dissociated by the local electric field. These results demonstrate that the PWP method can be applied to the study of high-voltage cables.< >
Coaxial
High Voltage
Cite
Citations (9)
This paper applies genetic arithmetic to the inverse problem in electric-field of high voltage insulators, finding an optimized solution for the inverse problem in electric-field and establishing an optimization calculation model. After measuring the electric-field of measuring points in the vicinity of insulator strings, calculating the actual voltage distribution along the insulator string by the method of charge simulation and genetic arithmetic, then comparing the actual voltage distribution with the standard distribution of the voltage along the insulator string, according to that can make sure whether there are defective insulators and the approximate position of defective insulators. The optimization calculation can increase precision of non-touch electric field mapping method, and detect defective insulator well and truly.
Cite
Citations (0)
This paper present results of tests conducted in the High Voltage Laboratory of the Ohio State University and deals with power frequency AC sparkover voltage measurement of small air gaps. Emphasis was placed on obtaining breakdown characteristics of electrodes and air gap separations that are representative of power lines 69 kV and below. Besides the customary rod-rod, rod-plane, and sphere-plane arrangements, other electrode configurations included various conductor sizes with conductor-rod, -plane, and -sphere arrangements and conductor-hot stick configurations with hook, puller, and wire brush accessories. It was found that the conductor size has a significant effect on the sparkover voltage. In addition, for the more practical electrode arrangement involving conductors, the sparkover voltages were greater than the rod-rod results in all but a few instances.
Air gap (plumbing)
Cite
Citations (12)