HVAC Breakdown of R12, R12 – Air Mixtures in Sphere gap Electrodes and Proposed Composite insulating Liquid to Reduce the Amount of Transformer Oil In Transformers

Research Paper (postgraduate) , 2013 , 5 Pages

Engineering - Power Engineering

Breakdown behavior of a 10 mm point-sphere gap is investigated for R12, R12 (Dichlorodifluoromethane, CCL2F2), air mixtures for pressures of up to 60psi. It is shown that at high gas pressures, mixtures containing high R12 content can have breakdown voltages higher than the corresponding values in air. Furthermore, these voltages are compared with the SF6. And make a comparison of R12 and SF6 in different scenarios i.e. GWP, cost, dielectric strength. Then Ac voltage breakdown characteristics of various combinations of insulating filler in transformer oil for use in transformers were investigated, with the aim of reducing the amount of oil and thus the cost. Tests were conducted on a sphere–sphere electrode in a horizontal arrangement and a sphere–plane electrode in a vertical arrangement. The Breakdown characteristics were also investigated in a modal in which Nomex paper was inserted between filler and the high-voltage electrode. Based on the experiments, optimum conditions are proposed for the application of transformer oil to transformers. Detailed results of investigations of both gas and composite insulating oil are described and discussed in this paper.

Inhaltsverzeichnis (Table of Contents)

• Introduction
  • Gas
  • Composite Liquid
• Experimental Arrangements and Procedures
  • Gas
  • Composite Liquid
• Experimental Results
  • Gas
  • Composite Liquid
• Conclusion
• References

Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)

This research paper investigates the breakdown behavior of R12 and R12-air mixtures in sphere gap electrodes for use in high-voltage applications, exploring their potential as alternatives to SF6 gas. It also examines the breakdown characteristics of various composite insulating liquids in transformers to reduce the amount of transformer oil required. The main objectives include:

• Investigating the breakdown voltage of R12 and R12-air mixtures at different pressures.
• Comparing the breakdown characteristics of R12, SF6, and air, considering factors like global warming potential (GWP), cost, and dielectric strength.
• Exploring the effects of different filler materials, including glass beads and Nomex paper, on the breakdown voltage of transformer oil.
• Proposing optimized conditions for using composite insulating liquids to reduce the amount of transformer oil required.
• Analyzing the breakdown mechanism and spark formation in R12 and R12-air mixtures.

Zusammenfassung der Kapitel (Chapter Summaries)

Introduction

This chapter discusses the rationale for exploring alternatives to SF6 gas, highlighting its environmental impact and safety concerns. It also introduces the concept of composite insulating liquids as a way to reduce the amount of transformer oil needed.

Experimental Arrangements and Procedures

This chapter describes the experimental setup and procedures used to investigate the breakdown behavior of R12 and R12-air mixtures, as well as the breakdown characteristics of composite insulating liquids. It outlines the electrode configurations, pressure vessel specifications, and testing methods employed.

Experimental Results

This chapter presents the experimental findings on the breakdown voltage of R12 and R12-air mixtures at different pressures. It also analyzes the breakdown characteristics of the composite insulating liquids, showcasing the impact of filler materials, Nomex paper, and the ratio of filler to oil. The chapter includes visual representations of the spark formation in R12-air mixtures and examines the byproducts formed during the decomposition of R12.

Schlüsselwörter (Keywords)

This paper focuses on high-voltage insulation, dielectric strength, environmental impact, global warming potential, SF6 gas, R12 gas, composite insulating liquids, transformer oil, glass beads, Nomex paper, breakdown voltage, spark discharge, and decomposition byproducts. The research aims to develop alternative insulation materials that are environmentally friendly, cost-effective, and perform well in high-voltage applications.

• Course: POWER SYSTEM ENGINEERING
• Authors: Muhammad Junaid (Author), Mehran Tahir (Author), Muhammad Aamir (Author)
• Publication Year: 2013
• Pages: 5
• Catalog Number: V229763
• ISBN (eBook): 9783656457985
• Language: English
• Tags: hvac, breakdown, mixtures, sphere, electrodes, proposed, composite, liquid, reduce, amount, transformer, transformers