Analysis of Zinc Oxide Grain Barrier under Slow-Front Overvoltages

Lutendo Muremi, Pitshou Bokoro

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

The analysis presented in this work highlights the impact of slow-front overvoltages on the microstructure of zinc oxide (ZnO) varistors. Grain boundaries in ZnO varistors play a significant role in determining the overall electrical characteristics. The variation effects influence the varistor's electrical behavior, dielectric strength and nonlinear response of applied voltages. The impact of several surges applied on ZnO grain barrier height changes was deduced from the C-V characteristic curve measurements conducted before and after degradation. The Kruskal-Wallis Test is then applied to analyze the effect. ZnO varistor microstructure is studied using the SEM while the chemical composition is analyzed using EDS. Results indicate a significant decrease in grain barrier height with an increased number of surges applied, with the observed decreases in barrier height response ranging from 6.8% to 23.57% for manufacturer A and 16.75% to 40.32% for manufacturer B.

Original languageEnglish
Title of host publication2024 IEEE PES/IAS PowerAfrica, PowerAfrica 2024
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9798350389388
DOIs
Publication statusPublished - 2024
Event2024 IEEE PES/IAS PowerAfrica, PowerAfrica 2024 - Johannesburg, South Africa
Duration: 7 Oct 202411 Oct 2024

Publication series

Name2024 IEEE PES/IAS PowerAfrica, PowerAfrica 2024

Conference

Conference2024 IEEE PES/IAS PowerAfrica, PowerAfrica 2024
Country/TerritorySouth Africa
CityJohannesburg
Period7/10/2411/10/24

Keywords

  • EDS
  • Electrical degradation
  • grain barrier height
  • insulation failure
  • Kruskal test
  • SEM
  • switching surges

ASJC Scopus subject areas

  • Geography, Planning and Development
  • Strategy and Management
  • Computer Networks and Communications
  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment
  • Electrical and Electronic Engineering
  • Control and Optimization

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