Enhancing Power Grid Security: How Dry-type Pre-insulated Bushings Eliminate Leakage Risks

During routine substation inspections, maintenance personnel frequently encounter the problem of oil leakage in oil-paper insulation systems due to aging seals. This not only pollutes the environment but can also lead to insulation breakdown. Through innovations in materials science and processes, the pre insulated sleeve module completely eliminates the internal fluid medium, providing a new path for the long-term stable operation of power systems.

Solid Insulation Core Structure

The core of this new component lies in its epoxy resin vacuum-impregnated fiber structure. Unlike traditional oil-paper capacitor cores, the pre insulated junction sleeve module highly composites the insulating material with the capacitor screen during manufacturing, forming a robust entity.

• Oil-Free Design: Contains no mineral oil, fundamentally eliminating the risk of oil spraying caused by pressure fluctuations.

• Composite External Insulation: Typically equipped with silicone rubber skirts, it offers stronger resistance to flashover and shock absorption compared to brittle ceramic materials.

• Field Strength Distribution Control: The built-in, precisely designed capacitor screen achieves uniform electric field distribution in a completely solid medium, reducing the probability of partial discharge.

Technical Performance of Pre-insulated Bushings in Extreme Environments

Mechanical Strength and Installation Flexibility

With no internal flowing medium, the installation angle of the pre-insulated bushing is no longer restricted. Whether installed vertically, horizontally, or at an angle, its internal insulation performance remains consistent. In earthquake-prone areas or high-vibration environments, the solid-encapsulated structure exhibits extremely high mechanical stability, reducing the risk of seal failure due to physical impact.

Long-Term Evolution of Insulation Performance

This component exhibits extremely low and stable dielectric loss factor during operation. The solid insulation layer effectively prevents atmospheric moisture intrusion, solving the problem of moisture absorption in oil-paper insulation. This characteristic is particularly prominent under high-temperature or high-load operation, effectively extending the service life of transformer accessories.

Note: The partial discharge of modern dry bushings is typically controlled below 5pC, far exceeding the industry standard requirement of 10pC. This is mainly due to the vacuum impregnation process eliminating all internal air gaps.

Structural Reduction in Operation and Maintenance Costs

In traditional inspection processes, maintenance personnel must periodically take oil samples for testing, observe the oil level gauge, and check the condition of the sealing rings. After adopting the insulated joint sleeve standard, the previously complex oil maintenance process has been simplified.

Routine inspections only require monitoring surface temperature and observing the cleanliness of the external insulation using an infrared thermal imager. This shift from "reactive maintenance" to "condition monitoring" significantly reduces the long-term operating costs of substations. In unattended substations, this maintenance-free characteristic demonstrates extremely high application value.