Optimization and Prediction of  Dielectric Behavior of Air Gaps 

OPTITHESI

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Workpackage 1: Methodology design

Workpackage 2: Supply and installation of devices

Workpackages 3: Mathematical models of the experimental arrangements

Workpackage 4: prediction of the dielectric behavior based exclusively on simulation

Workpackage 5: Reform the Corona Current Rule and develop it into a Theorem



Methodology, Work packages

The physical object of the proposed project will be developed into three parallel branches. The first branch concerns the experimental investigation, the second one refers to the simulation analysis and the third one is focused on the mathematical analysis.

The comparison of the experimental results with the results from analysis and the connection between theory, simulation and experiments will lead to the basic aim of the research project.


In particular within the proposed research project the following actions are programmed to be fulfilled:

   1. The experimental investigation of the dielectric behavior of air gaps of different geometry (especially the rod-plate and rod-rod arrangements), as far as the Corona onset, the Breakdown voltage and the Corona current are concerned. The diameters of the rods will be up to 12 mm, the diameters of the plates up to 200 mm and the gaps length up to 100 mm. There will be no sharp points or edges in the arrangements, except of the rod tips, in order for the corona effects to be localized on these tips. The voltage forms to be applied will be dc voltage of positive and negative polarity, ac voltage, as well as lighting and switching impulse voltage.

   2. The theoretical analysis of the initial conditions that influence the electric field distribution in an air gap arrangement, with or without barrier, and with different ways of grounding, and charging.

   3. The analysis via simulation of the field distribution in different air gap arrangements and the measurement and recording of the differences between arrangements with one electrode grounded and arrangements with symmetrically charged electrodes. The simulation will be accomplished via the Finite Element Method and the use of special software. Extra importance will be given to the analysis of rod – plate air gaps without a barrier, as well as of correspondent air gaps with a barrier.

   4. The investigation of the connection of the analytical and simulation results with the experimental results, and the formation of models describing the relation between theory/analysis and experiments.

   5. The theoretical analysis and the analysis via simulation of the influence of space charge on the distribution of the electric field in a gap.

The completion of the above mentioned investigation actions will lead to the basic aim of the project, which are:

     1.The development of equation models capable to lead to the optimization of the dielectric behavior of an air gap and models to predict whether a specific gap will suffer corona or breakdown, and

     2.The formation and proof of the Corona Current Theorem.

The methodology to be developed will be as follows:

  1. The design and the preparation of the experimental arrangements and of the mathematical and simulation models.
  2. The experimentation and the measurements of the Corona Onset voltage, the corona current and the Breakdown voltage of air gaps in combination with the Polarity and the Barrier Effects, and the use of dc, ac and impulse voltages.
  3. The mathematical analysis of the models designed and the formulation of the equations of initial conditions of the electric field analysis.
  4. The simulation analysis of the models designed and the record of the field strength in the gap.
  5. The comparison of the theoretical and experimental results and the formulation of equation models to specify and describe the dielectric behaviour of the gaps.
  6. Investigation of the ways to optimize the dielectric behaviour (Corona and Breakdown) of the gaps.
  7. Investigation of the possibility to predict the dielectric behaviour (Corona and Breakdown) of the gaps, using exclusively the results of the simulation analysis.
  8. Attempt to reform the Corona Current Rule and develop it into a Theorem.

The whole project will be consisted of 5 Work Packages, as follows:


Workpackage 1: Methodology design. Work will be held in the T.E.I of Larissa and the N.T.U.A with the participation of all professors, team members and some of the Co-investigators, aiming to the final preparation of the methodology and project management. Two meetings at least will be held in Larissa and Athens. A website of the project will be created.


Workpackage 2: The supply and installation of devices, the design, the construction and the preparation of the experimental arrangements and software installation will be completed. Experimental work on air gaps of different geometry will be carried out. The values of the Corona onset and the Breakdown dc, ac and impulse voltage, as well as the corona current through the gaps will be measured and recorded in connection to the effects of grounding and barrier. The experimental results will be processed and the first papers will be written. Work will be performed in the High Voltage laboratories of the T.E.I. of Larissa and the N.T.U.A. with the participation of members Prof. Dr A. Maglaras, V. Dafopoulos and F. Topalis, and Collaborators Dr I. Gonos, K. Giannakopoulou, T. Kampisios, A. Aggelidis, and K. Bouroussis.


Workpackages 3: Mathematical models of the experimental arrangements will be designed, and the equation of initial conditions concerning the analysis of the electric field in the gaps, in connection to the ground and the barrier effect will be formulated and analyzed. Appropriate models will be designed and simulation analysis via special software will be held. The values of the voltage, the field strength and field energy in different positions in the gaps, under different conditions, and in combination with the effects of grounding, barrier and Corona current will be recorded and processed. A connection between mathematical, simulation and experimental results and the formation of equation models describing the dielectric behavior of air gaps with or without barrier will be developed. Work will be carried out in the High Voltages and Computer laboratories of the T.E.I. of Larissa mainly and the N.T.U.A. secondary and the Prof Dr members participating will be T. Kousiouris, A. Maglaras, A. Kladas, A. Nassikas, V. Dafopoulos, and D. Katsaros, as well as the Collaborators I. Gonos, L. Maglaras, and K. Giannakopoulou.


Workpackages 4: The equation models that will be formed in the WP 3 will help to optimize the values of corona onset voltage, breakdown voltage, Corona current and Corona losses in connection to the Ground, and the Barrier Effect. Research towards the prediction of the dielectric behavior based exclusively on simulation will follow. Work will be carried out in the High Voltages and Computer laboratories of the T.E.I. of Larissa mainly and the N.T.U.A. secondary and the Prof Dr members participating will be A. Maglaras, F. Topalis, and T. Kousiouris, as well as the Collaborators L. Maglaras, and K. Giannakopoulou. Papers will be prepared


Workpackage 5: Using the existing so far mathematical field equations combined with simulation and experimental results connecting the Corona Current with Breakdown voltage, there will be an attempt to reform the Corona Current Rule and develop it into a Theorem, after it is mathematically proven. Papers will be prepared. Work will be held in the computer laboratories of the T.E.I. of Larissa and the N.T.U.A. and the members participating will be T. Kousiouris, A. Maglaras, F. Topalis, D. Katsaros, A. Nassikas, and Collaborators L. Maglaras and K. Giannakopoulou.