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1
Content available Prądy spowodowane przemieszczaniem się mikrocząstek w wysokonapięciowych próżniowych układach izolacyjnych
Twardosz G., Opydo W., Stawicki J.
Poznan University of Technology Academic Journals. Electrical Engineering
|
2017
|
No. 90
185--193
PL
W pracy przedstawiono wyniki obliczeń wartości szczytowych i czasów trwania impulsów prądowych spowodowanych przelotem mikrocząstek metalicznych miedzy elektrodami wysokonapięciowego próżniowego układu izolacyjnego. Obliczenia przeprowadzono przy założeniu, że przemieszczające się mikrocząstki są wykonane z miedzi lub aluminium i mają kształt kuli o promieniu od 0,1 μm do 100 μm, długość przerwy międzyelektrodowej układów wynosi 10 mm, a napięcie na zaciskach ma wartość 100 kV lub 200 kV. Dla tych warunków największy obliczony impuls prądowy, spowodowany przelotem największej mikrocząstki (o promieniu równym 100 μm) miał wartość szczytową 2 · 10-7 A i trwał 2 ms. Do obliczeń wykorzystano program komputerowy napisany w środowisku Visual Studio 2013 w języku programowania C#.
EN
The paper presents results of the calculations of the maximum values and duration of electric impulses caused by motion of metallic microparticles between electrodes in high-voltage vacuum insulated systems. Calculations were based on the assumption that microparticles are made of copper or aluminum and are spherical in shape with radii ranging from 0.1 to 100 μm, 10 mm length of system vacuum gap and 100 kV or 200 kV voltage at the terminals of a vacuum insulation system. For these conditions the highest calculated electric impulse, caused by the motion of the biggest microparticle (with radius of 100 μm) reached maximum values of 2 · 10-7 A and lasted 2 ms. Calculations were performed with the computer program developed in C# language on the Visual Studio 2013 environment.
2
Content available Sulphur hexafluoride as a high-voltage insulation - selected problems
Opydo W., Juszczyk Z., Stawicki J., Opydo-Szymaczek J.
Computer Applications in Electrical Engineering
|
2014
|
Vol. 12
206--216
EN
The paper presents some selected properties of sulphur hexafluoride (SF6) a medium used for high-voltage insulation and electric arc suppression purposes. The results are presented of the studies aimed at determining the effect of the electrode material type, temperature, gas density and interelectrode gap on the SF6 electric strength. The considered systems had both flat electrodes or one flat and the other (cathode) having the form of a rod of 3 mm or 30 mm diameter, ended with a hemisphere. The electrodes have been made of stainless steel or aluminum. The results were mathematically processed with the use of the Statistica [11] computer software. It was found that SF6 temperature changes in the range from 243 K to 293 K with constant SF6 density did not cause variation of electric strength of the gas. Moreover, the effect of the electrode material type on electric strength of SF6 was observed only in the systems distinguished by macroscopic uniformity of the electric field and in case of the gas density exceeding 15 kg/m3, corresponding to SF6 pressure amounting about to 2.5-105 Pa in the temperature 293 K. Physical interpretation of the study results is proposed and formulated. Additionally, the paper discusses the hazards arising from the use of SF6 for the health of the persons operating the equipment and for the environment.
3
Content available Analiza porównawcza próżni i sześciofluorku siarki jako izolacji wysokiego napięcia
Opydo W., Stawicki J.
Poznan University of Technology Academic Journals. Electrical Engineering
|
2013
|
No. 74
181--186
PL
W pracy przedstawiono wyniki pomiarów wytrzymałości elektrycznej przy napięciu przemiennym (50 Hz) układów izolacyjnych: próżniowego, z sześciofluorkiem siarki (SF6) i z olejem mineralnym. Badane układy miały elektrody płaskie wykonane ze stali nierdzewnej lub aluminium. Stwierdzono, że układy izolacyjne: próżniowy, z SF6 o ciśnieniu 3x105 Pa oraz układ z olejem mineralnym, przy tym samym kilkumilimetrowym odstępem międzyelektrodowy, mają w przybliżeniu taką samą wytrzymałość elektryczną. Wskazano na zalety i wady próżni, SF6 i oleju mineralnego w kontekście zastosowania tych ośrodków jako izolacji wysokonapięciowej w określonym rodzaju urządzeń elektrycznych. Do opracowania matematycznego wyników badań wykorzystano program komputerowy Statistica [3].
XX
The paper presents the results of the measurements of electric strength under a. c. voltage (50 Hz) of the insulation systems based on vacuum, sulfur hexafluoride and pure mineral electric insulating oil. The studied systems had electrodes with rounded-off edges of Rogowski’s profile, made of stainless steel or aluminum. The study revealed that the insulation systems based on vacuum, sulfur hexafluoride at 3x105 Pa pressure and mineral oil with the same a few millimeters interelectrode gap spacing have similar electric strength. Advantages and disadvantages of vacuum, sulfur hexafluoride and mineral oil were pointed out regarding the use of these media as a high voltage insulation in particular type of electric devices. Statistica [3] software was used for mathematical analysis of the results.
4
Content available Review and comparison of electro-insulation properties of vacuum and sulphur hexafluoride
Opydo W., Stawicki J., Opydo-Szymaczek J.
Computer Applications in Electrical Engineering
|
2013
|
Vol. 11
222--229
EN
The paper specifies the results of the tests on electric strength of vacuum, sulphur hexafluoride (SF6) and the insulation mineral oil under alternate voltage. The tests have been carried out for planar electrodes made of stainless steel or aluminum. It was found that 10-3 Pa vacuum, 3 105 Pa SF6, and insulation mineral oil situated with equal inter-electrode gap equal to several millimeters, have approximately equal electric strength. The degrees of influence of basic parameters of the insulation system on electric strength of SF6 and vacuum are presented. Advantages and faults of vacuum, SF6, and insulation mineral oil are mentioned, taking into account possible use of these media as a high-voltage insulation in various electric equipment. Mathematical processing of the test results was carried out with the use of the Statistica software [5].
5
Content available Uproszczona metoda pomiaru współczynnika przewodzenia ciepła gruntu
Stawicki J., Opydo W.
Poznan University of Technology Academic Journals. Electrical Engineering
|
2012
|
No. 72
49--56
PL
W pracy przedstawiono uproszczoną metodę pomiaru wartości współczynnika przewodzenia ciepła gruntu. Zaproponowana metoda pozwala na częściowe wyeliminowanie błędów pomiarów związanych ze zmianami struktury i gęstości gruntów, które występują przy stosowaniu tradycyjnych metod. Jednocześnie pozwala z zadawalającą dokładnością wyznaczać wartość tego współczynnika. Do opracowania matematycznego wyników badań wykorzystano program komputerowy Statistica.
EN
Results of the study on elaboration of the simple method of the measurement of the ground thermal conductivity coefficient, which may be used directly in the field, were presented in the paper. Measurement system, connected to probes-thermistor sensors, that were situated in examined ground, was designed and built. Two types of sensors: active and passive were used. Active sensor, apart from thermistor for temperature measurements, had additional electric heating element. The study revealed that method proposed allows to determine, with satisfying precision, the value of the ground thermal conductivity coefficient. At the same time, the method partially eliminates measurement errors associated with changes of the structure and density of examined grounds, which occur during measurements with the use of traditional methods. STATISTICA software was used for mathematical analysis of the results
6
Content available Studies on development of an electrothermal method of measuring the soil thermal conductivity
Stawicki J., Opydo W.
Computer Applications in Electrical Engineering
|
2012
|
Vol. 10
118--126
EN
The paper presents the studies on development of a simplified electrothermal method of measuring the soil thermal conductivity, that may be used directly in the field. A measurement system has been designed and built, that is connected to measuring sensors located in the examined soil. Two types of sensors, i.e. active and passive ones were used. The passive sensors were provided with thermistors used for temperature measurement, while the active one, apart from the thermistor, was provided with a heating element of resistance type. The study has shown that the proposed method, consisting in measuring the steady heat conduction between the measuring sensor and soil, allows to determine the value of the soil thermal conductivity with satisfying accuracy. Moreover, the method is conducive to significantly smaller disturbance of the soil structure, being a reason of measurement errors occurring while using traditional methods. Mathematical processing of the research results has been carried out with the help of STATISTICA software.
7
The use of electroosmosis for drying building materials
Stawicki J., Opydo D., Opydo W.
Poznan University of Technology Academic Journals. Electrical Engineering
|
2011
|
No. 67-68
115-121
EN
The paper presents results of a research study that examined electroosmosis application for drying of building materials - cellular concrete block and brick. It was found that the effectiveness of electroosmosis in drying brick is much higher than that in drying cellular concrete blocks. This is probably due to high porosity of cellular concrete, which increases a capillary influx of water into the material, largely negating the effect of electroosmosis. For mathematical processing of the research results the computer software STATISTICA has been used.
8
The use of AHP Method for evaluation and selection of subcontractors
Opydo D., Iskierka S., Stawicki J.
Poznan University of Technology Academic Journals. Electrical Engineering
|
2010
|
No. 63
149-155
EN
The paper presents the procedure of multicriteria evaluation and selection of subcontractors. The procedure developed for this purpose makes use of the AHP Method (Analytic Hierarchy Process) that enables analyzing multicriteria decision problems and assists decision making. The paper presents the process of subcontractor selection and its possible effect on financial condition of a company. The results of example decision process effected with the use of the MakeltRational software.
9
Content available remote Econometric model for analysing the cost of failures of technical objects operated within the municipal public transport system
Stawicki J., Woropay M.
Archives of Transport
|
1999
|
Vol. 11, iss.1-2
63-72
EN
The paper presents the principles of cost analysis for failures of technical objects on the basis of a regression model. A model to test actual municipal transport systems was suggested and developed. The analysis of results obtained from the model was presented in the form of equations and charts.
PL
W artykule przedstawiono zasady analizy kosztów uszkodzeń obiektów technicznych na podstawie modelu regresyjnego. Model wykorzystano w badaniach miejskiego systemu transportowego. Uzyskane wyniki zostały przedstawione w formie równań i wykresów.
10
Nowe technologie i metody zarządzania.
Klęczar J., Stawicki J.
Informatyka
|
1998
|
Wyd. specj. I
30-32
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