Stochasic nature of gas insulation pulse response

Рад разматра актуелну проблематику импулсног одзива гасне изолације у циљу развоја врло брзих електроенергетских електрогасних прекидаћа као и развоја фундаменталних истраживања у плазми. Полази се од гасних пражњења на микро основи, утврђују се основни закони пражњења на макро основи и долази до могућности предвиђања и контроле гасних пражњења. Полазећи од слућајности процеса механизма електричног пражњења у гасовима развијен је модел иницијације и развоја пражњења до пробоја разматрањем кумулативних процеса производње слободних електрона, настанка иницијалних електрона и развоја пражњења до пробоја (стримерским и Таузендовим механизмом) у реалном простору и у простору вероватноће. На бази овог модела развијен је закон пораста вероватноће импулсног пробоја уз истовремену промену све три просторне димензије изолационог система: анализиран је утицај повећања броја слободних електрона на стохастичност импулсног пробоја гасне изолације; одређен је утицај контаминације гасне изолације проводним и непроводним честицама на импулсни одзив гасне изолације и развијен метод теоријског рорачуна волт-секундних карактеристика гасне изолације.Actual problems of the pulse response of gas insulation are considered to achieve a development of very fast high energetic electro gas switches as well as the fundamental investigation of plasma. The fundamental laws of discharge at the micro bases are established and the possibility of prediction and control of the gas discharge are found, beginning from the analysis of the foundations of gas discharge at the macro base. A model of initiation and evolution of the electric discharge until the breakdown was developed by consideration of the cumulative processes in the production of free electrons, appearance of initial electrons and discharge evolution until the breakdown (using streamer and Townsend mechanisms) in the real and the probability spaces, proceeding from the incidental processes in the mechanisms of the electric discharge in gases. New model has enabled: the establishment of the law of pulse breakdown probability increase with change in all space dimensions of the insulating system at the same time; the analyses of the influence of the free electron number increase on the stochastic pulse breakdown of the gas insulation; determination of the influence of the gas insulation contamination by conducting and nonconducting particles on the pulse response of the gas insulation; and development of the method for theoretical calculation of the volt-second characteristics of the gas insulation. Theoretical results have been experimentally tested in the laboratories ali over the world

Influence of electromagnetic pollution of the electron beam generator and high-energy radioactive source on the memory components

The study con sid ers the im pact of the en vi ron men tal con tam i na tion by the elec tro mag netic ra di a tion of elec tron beam gen er a tor and high-en ergy ra dio ac tive source on the mem ory com - po nents. Electron beam gen er a tor can be used for in jecting parti cle en ergy into the plasma of the fusion sys tem based on a Marx gener a tor, while ra dio ac tive source as a sim u la tor of high-en ergy ion iz ing ra di a tion that can be caused by the neu tron-in duced ac ti va tion of plasma sur round ing struc tures or re leased from deu te rium-tri tium fu sion re ac tion. The ef - fects of gamma ra di a tion of high-en ergy radio ac tive source and elec tric field of the electron beam gen er a tor on EPROM and EEPROM semi con ductor com puter mem ory, were in ves ti - gated. An older mem ory types were de lib er ately cho sen for the rea son that their more ro bust con struc tion will better pro tect them from the ef fects of ioniz ing and non-ion iz ing ra di a tion. The re sults ob tained un der well-con trolled condi tions show a high de gree of non-re sis tance of the semi con duc tor tech nol ogy to the ex pected elec tro mag netic pol lu tion of the elec tron beam gen er a tor and high-en ergy radio ac tive source. This con clu sion raises doubts on the pos - si bil ity of si mul ta neous ap pli ca tion of elec tron beam gen er a tor, con se quently fu sion sys tem and nanotechnologies with the in creas ing need for min ia turiza tion of electronic com po nent

The determination of the mean value of the non-homogenous background radiation and the measurement uncertainty using welch-satterthwaite equation

In this paper, the procedure for determination of the mean value of non-homogenous background radiation and the expression of measurement uncertainty is considered. The background radiation is described using the Student's distribution, and the measurement uncertainty using the Welch-Satterthwaite equation. The proposed algorithm was experimentally verified under well-controlled laboratory conditions and satisfactory results were obtained

Influence of the synergy of neutron and gamma radiation and functional aging on the efficiency of a hybrid protection circuit

Due to the shortcomings of commercial filters and non-linear components for overvoltage protection in the conditions of synergy of neutron and gamma radiation and functional aging, the behavior of the hybrid protection circuit under the same conditions was examined. In order for the experimental procedure to correspond as closely as possible to the real situation, the load of the hybrid circuit was not adjusted by impedance. The standard model of the hybrid protection circuit recommended in accordance with IEC 1.3 is simulated using the software package PSPICE. To that end, it is necessary to create a varistor with appropriate elements. The equivalent inductance parameters were found to be stable in relation to the experimental conditions. It was also established that due to the synergy of neutron and gamma radiation and functional aging, there is a change in the steepness of the varistor characteristic and the tangent of the loss angle in the capacitors. The overall effect of neutron and gamma radiation and functional aging was tested on the hybrid circuit and on individual components. The experiments were performed under well-controlled laboratory conditions, and the combined measurement uncertainty of the experimental procedure did not exceed 5%

Possibility of application nuclear magnetic resonance for measurement of fluid-flow

The paper considers the application of nuclear magnetic resonance for measurement of fluid-flow. The paper is of an experimental nature. Flowmeter based on nuclear magnetic resonance is extremely precise. The combined measurement uncertainty can be 0.1 %. Such a value of measurement uncertainty indicates that it is a matter of a deterministic and not of a stochastic quantity. This high degree of reliability of the method is theoretically and mathematically described. The paper presents a measurement scheme for flow measurement. Water flow measurement was performed on the principle of nuclear magnetic resonance and on the basis of tritiated water (which is considered to be the most accurate classical method). The obtained results show that the measurement of flow based on nuclear magnetic resonance is more accurate (especially at higher flow). This is explained by the higher inertial mass of HTO tritiated water molecules than the standard H2 O mass and the possible transition of tritiated water to H3HeO. In this way, it has been proven that tracing water based on nuclear magnetic resonance is the only real tracing of water by water. The obtained results show that tracing water with tritiated or heavy water is not tracing water by water which is explained by different inertial masses

The influence of electrode material on gas-filled surge arresters response time in gamma and X radiation field

Cilj ovog rada je da se ispita uticaj materijala elektroda na impulsnu karakteristiku modela gasnog odvodnika prenapona u polju gama i X zračenja. Pokazano je da oba tipa zračenja dovode do povećanja brzine odziva odvodnika. Dobijeni rezultati pokazuju da je optimalno rešenje model odvodnika sa elektrodama od aluminijuma.The aim of this paper is to investigate the influence of electrode material on the gas-filled surge arresters' model pulse shape characteristic in gamma and X radiation field. We found that both radiations have increased gas filled surge arresters' response time. The obtained results show that the optimal solution for GFSA model is with Al electrodes.ETRAN : 51. konferencija ETRAN-a : Elektronski zbornik radova; Jun 4-8, 2007, Herceg Novi – Igal

The Impact of Radiation on Semiconducting Characteristics of Monocrystalline Silicon and Germanium

The paper examines the effects of radiation on the electrical characteristics of monocrystalline silicon and germanium. Samples of monocrystalline silicon and germanium are irradiated under controlled laboratory conditions in the field of neutron, X- and gamma-radiation. Change of the samples specific resistance was measured dependent on the radiation dose with the type of radiation as a parameter. Next, the dependence of the samples resistance on temperature was recorded (in the impurities region and in intrinsic region) with the previously absorbed dose as a parameter. The results were statistically analyzed and explained on the basis of radiation effects in solids. The results are compared with those obtained by using Monte Carlo method. A good agreement was confirmed by the mentioned experimental investigation

Insulation Co-Ordination and the Enlargement Law for the Gm Counter Tube

In this paper we analyze application of contemporary methods of insulation co-ordination and the enlargement law in designing a GM counting tube. It has been shown that by applying insulation co-ordination methods the counting tube can be optimally dimensioned. The application of the enlargement law was demonstrated in generalizing the results of test obtained by the GM tube to those obtained by the counting tube with m-times greater dimensions. The investigations were conducted both theoretically and by experiment. Using theoretical analysis, we derived the expressions that may be applied if a performance function of a random variable breakdown voltage is known. The experiments were conducted on a GM counter model under well controlled laboratory conditions

Passive and active shielding against electromagnetic radiation

In nuclear physics experiments, it is very important to isolate the measured quantities from electromagnetic noise. Without this possibility, it is impossible to obtain usable experimental results since natural electromagnetic noise can be several orders of magnitude larger than the measured magnitude. In order to enable such measurements, it is necessary to eliminate electromagnetic noise from the experimental procedure. This is achieved by shielding against electromagnetic radiation. In this paper, experiments were performed to protect a room from electromagnetic noise. By applying all known methods of shielding against electromagnetic radiation, it was concluded that the room can be protected from the electrical component, but it is impossible to protect it from the magnetic component of electromagnetic radiation

The effects induced by the gamma-ray responsible for the threshold voltage shift of commercial p-channel power VDMOSFET

The variations in the threshold voltage shift in p-channel power VDMOSFET during the gamma ray irradiation was investigated in the dose range from 10 to 100 Gy. The investigations were performed without the gate bias and with 5 V gate bias. The devices with 5 V gate bias exhibit a linear dependence between the threshold voltage shift and the radiation dose. The densities of radiation-induced fixed and switching traps were determined from the sub-threshold I-V characteristics using the midgap technique. It was shown that the creation of fixed traps is dominant during the irradiation. The possible mechanisms responsible for the fixed and switching traps creation are also analyzed in this paper