Детальная информация

Целью диссертационной работы является определение основных действующих факторов, влияющих на экранирующий эффект заземляющих устройств при ударе молнии. Заземляющие устройства обычно состоят из нескольких заземлителей, что может привести к экранирующему эффекту растекающегося тока. Мы провели 2D-моделирование одного вертикального заземляющего электрода и 3D-моделирование вертикальных заземляющих электродов в программе COMSOL Multiphysics. Для анализа работы систем заземления при воздействии молнии мы использовали конечно-элементное моделирование электромагнитных полей. По результатам сравнительного анализа результатов моделирования одного и нескольких электродов были определены основные действующие факторы, влияющие на экранирующий эффект вертикальных заземляющих электродов при ударе молнии. При этом в качестве основных влияющих факторов рассматривались такие факторы, как различные параметры грунта, расстояние между электродами и размещение электродов. Результаты сравнивались путем исследования электродов на разных расстояниях и при разных параметрах почвы.

The aim of the thesis is the determination of the main acting factors that affect the shielding effect of grounding devices under lightning impact. Grounding devices usually consist of a number of grounders, which can lead to the shielding effect of the spreading current. We simulated 2D modeling of the one vertical grounding electrode and 3D modeling of the vertical grounding electrodes at COMSOL Multiphysics software. For analyzing the working of the grounding systems under lightning impact we used finite element modeling of the electromagnetic fields. We identified the main acting factors which affect the shielding effect of the vertical grounding electrodes under lightning impact according to a comparison thorough analysis of the results of the modeling of one and the number of the electrodes. In this case, factors such as different soil parameters, the distance between the electrodes, and the placement of the electrodes determined as the main influencing factors were examined. The results were compared by examining the electrodes at different distances and soil parameters.

• INTRODUCTION
• CHAPTER 1. LITERATURE REVIEW
  • 1.1. Overvoltage in the Power System
  • 1.2. Types and Causes of Overvoltage
    • 1.2.1. Internal Causes
    • 1.2.2. External Causes
  • 1.3. Lightning
    • 1.3.1 Types of Lightning Strikes
    • 1.3.2 Methods of Protection Against Lightning
  • 1.4. Main Principles of Grounding Devices and Grounding
    • 1.4.1. Types of Grounding Systems
    • 1.4.2. Characteristics of an Effective Grounding System
    • 1.4.3. Grounding Electrode
  • 1.5. Impedance of the Grounding Devices
    • 1.5.1. Fall of Potential Method
    • 1.5.2. %62 Method
    • 1.5.3. The Clamp-On Method
    • 1.5.4. Dead Earth Method
    • 1.5.5. Frequency Sweep Method
  • 1.6. Shielding Effect
    • 1.6.1. Types of Shielding Effect at Grounding devices
• AIM AND OBJECTIVES
• CHAPTER 2. 2D MODELING OF THE VERTICAL GROUNDING ELECTRODE UNDER LIGHTNING IMPACT.
  • 2.1. Main Equations of Electric Field
  • 2.2. Main Equations of Magnetic Field
  • 2.3. How to Couple Electric Field and Magnetic Field Equations
  • 2.4. Simulation of 2D Modeling of the One Vertical Grounding Electrode Under Lightning Impact
    • 2.4.1. Results
• CHAPTER 3. 3D MODELING OF THE NUMBER OF THE VERTICAL GROUNDING ELECTRODE UNDER LIGHTNING IMPACT
  • 3.1. Simulation of 3D Modeling of One Vertical Grounding Electrode Under Lightning Impact
    • 3.1.2. Results
  • 3.2. Simulation of 3D Modeling of Two Vertical Parallel Grounding Electrode Under Lightning Impact
    • 3.2.1. Results
  • 3.3. Simulation of 3D Modeling of Four Vertical Parallel Grounding Electrode Under Lightning Impact
    • 3.3.1. Results
  • 3.4. Simulation of 3D Modeling of Vertical Four Parallel Grounding Electrodes With Different Lenghts Under Lightning Impact
    • 3.4.1. Results
• CHAPTER 4. ANALYSIS OF MODELING OF THE NUMBER OF THE VERTICAL GROUNDING ELECTRODE UNDER LIGHTNING IMPACT
  • 4.1. Analysis of 2D Modeling of the One Grounding Electrode Under Lightning Impact
  • 4.2. Analysis of 3D Modeling of Two Vertical Parallel Grounding Electrode Under Lightning Impact
  • 4.3. Comparing Graphs of 2D Modelling of the One Grounding Electrode With 3D Modelling of two Vertical Parallel Grounding Electrodes Under Lightning Impact
  • 4.2. Analysis of 3D Modeling of Four Vertical Parallel Grounding Electrode Under Lightning Impact
  • 4.4. Comparing Graphs of 2D Modelling of the One Grounding Electrode with 3D Modelling Of Four Vertical Parallel Grounding Electrodes Under Lightning Impact
  • 4.5. Comparing Graphs of 3D Modelling of the Two Vertical Parallel Grounding Electrode with 3Dd Modelling of Four Vertical Parallel Grounding Electrodes Under Lightning Impact
  • 4.6. Analysıs of 3D Modeling of Four Vertical Parallel Grounding Electrode with Different Lenghts Under Lightning Impact
• CONCLUSION
• REFERENCES