A bushing is a device for carrying one or more high-voltage conductors through an earthed barrier such as a wall or a metal tank. It must provide electrical insulation for the rated voltage and for service overvoltages and also serve as mechanical support for the conductor and external connections. The requirements for bushings are specified in IEC 60137: 2008.

Chapter Contents:

• 12.1 Introduction
• 12.2 Types of bushings
• 12.2.1 Non-condenser bushings
• 12.2.2 Condenser bushings
• 12.3 Bushing design
• 12.3.1 Air end clearance
• 12.3.2 Oil-end clearance
• 12.3.3 Radial gradients
• 12.4 Bushing applications
• 12.4.1 Transformer bushings
• 12.4.2 High-current bushings
• 12.4.3 Direct connection to switchgear
• 12.4.4 Switchgear bushings
• 12.4.5 Direct current bushings
• 12.5 Testing
• 12.5.1 Capacitance and dielectric dissipation factor measurement
• 12.5.2 Power frequency withstand and partial discharge measurement
• 12.5.3 Impulse voltage tests
• 12.5.4 Thermal stability test
• 12.5.5 Temperature rise test
• 12.5.6 Other tests
• 12.6 Maintenance and diagnosis
• References

Inspec keywords: overvoltage protection; high-voltage engineering; IEC standards; bushings

Other keywords: metal tank; electrical insulation; high-voltage bushings; IEC 60137:2008; rated voltage; service overvoltages; mechanical support; high-voltage conductors; earthed barrier

Subjects: Power system protection; Power line supports, insulators and connectors