Technical Information


Because of no-polarity alternation in DC voltage,specific technical subjects shall be considered.

Technical Subjects for DC Insulators

1. Contamination Withstand Voltage Characteristics

Contamination Withstand Voltage Characteristics1

Contamination Withstand Voltage Characteristics2

Solution DC Fog type Insulator

2. Insulator Deterioration

Surface erosion, Ion migration due to DC stress

Insulator Deterioration

Solution High Quality DC Porcelain Insulator

3. Electrolytic Corrosion of Pin

Electrolytic corrosion due to DC leakage current

Electrolytic Corrosion of Pin

Solution Zinc Sleeve

HVDC Service Experience

Experience is one of the most important considerations in choosing insulators for High Voltage Direct Current power transmission, because special design and materials are necessary to solve such problems as DC contamination, ion migration and thermal runaway, issues unique to HVDC transmission.

NGK has been providing customers with solutions for HVDC insulators, knowledge gained from extensive field experience as well as research and development at our High Voltage Lab.

Over the past 20 years, NGK group has supplied more than 70% of the suspension insulators required for the world's HVDC projects.

  • ± 350 kV Leyte - Luzon, Philippines
  • ± 450 kV James Bay, Canada
  • ± 500 kV Rehand - Delhi, India
  • ± 500 kV Gezhouba - Shanghai, China
  • ± 500 kV Chandrapur - Padghe, India
  • ± 500 kV Anan - Kihoku, Japan

Inquiry about Technical Information

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