Description:

Medium-voltage transformer bushings are insulating components that enable energized conductors to pass safely through a transformer’s grounded tank, ensuring electrical isolation and mechanical support. They are essential for maintaining the integrity and safety of electrical distribution systems.

Key Functions:

Insulation: Bushings provide a barrier between the high-voltage conductor and the grounded transformer tank, preventing electrical faults and ensuring safe operation.

Mechanical Support: They support the conductor mechanically as it passes through the transformer enclosure, maintaining alignment and structural integrity.

Types of Medium-Voltage Bushings:

Solid (Bulk) Type: Constructed from materials like porcelain or epoxy, these bushings are commonly used for lower voltage applications. They provide basic insulation and are simpler in design.

Capacitance-Graded (Condenser) Type: Designed for higher voltage applications, these bushings incorporate layers of conductive and insulating materials to evenly distribute electrical stress, enhancing performance and reliability.

Materials Used:

Porcelain: Traditionally used due to its durability and insulating properties.

Epoxy Resin: Offers advantages such as reduced weight and improved performance in contaminated environments.

Design Considerations:

Voltage Rating: Bushings are designed to handle specific voltage levels, ensuring they meet the requirements of the electrical system.

Current Rating: They must support the expected current load without overheating or degrading.

Environmental Factors: Considerations include exposure to weather, pollution, and other environmental conditions that could affect performance.

Proper selection and maintenance of medium-voltage transformer bushings are crucial for the safe and efficient operation of electrical power systems. Regular inspections and testing can help identify potential issues before they lead to equipment failure.

These are used for connections to transformers indoors or outdoors. The operating voltage lies between 12 kV and 36 kV and the current range from 250 – 3150 A. Flexibility and simplicity make this bushing a robust solution for many applications.