Transformers are a key component and one of the more expensive pieces of equipment found in a distribution network.

Preventative maintenance is often overlooked because Transformers can offer long-term robust service, but today with the need for non-linear loads and the addition of Distributed Generation, transformer long term sustainability and reducing age acceleration is a key consideration. Generally, transformers are designed to function within their nameplate ratings, yet, in certain situations as in the case cited above, they are often loaded above the nameplate ratings. In underground network distribution environments, the transformers are by design overloaded for contingencies as a standard practice.

When transformers operate they tend to generate large quantities of heat. The conversion of the energy inside the transformer is the reason for this heat. The generated heat varies with the load that is applied to the transformer. The higher the load, the higher will be the generated heat, due to the windings and also due to the associated core losses. The generation of heat cannot be avoided and consideration must be given to methods to control, cool, and monitor thermal performances.

One of the main consequences of heat generation in transformers is accelerated aging which can be a legitimate public safety concern as these transformers are oil-filled to aid in the cooling and any fault within the confines of the transformer can be catastrophic. This is combined with the applied application of transformer in underground vaults directly below pedestrian sidewalks with built-in natural convection grates that we walk over every day in major city centers.

These built-in grates give some natural convection flow but are very limited in controlling the ambient temperature of the load environment and are exposed to the public and often a repository for trash, floodwaters, and other contaminants.

The VaultVent^™ is specially designed to address these concerns. The built-in exhaust fan maintains the correct ambient temperature while pulling hot thermals away for the equipment maintaining both the life and safety of the surroundings. This design would eliminate the need for exposed, open gratings and would provide smart thermal control. Our standard design is a tamper-proof pedestal or can offer in the way of a custom park bench design with built-in integral fans, extremely quiet in operation.

Traditional Open Grates in the Electrical Underground

Typically, underground electrical vaults are provided with sidewalk open grates for some natural convection advantages, but the disadvantages are many:

• Exposure to roadside salts leading to equipment corrosion and failures
• Exposure to debris dropping down in the vault
• Exposure to contamination dumping by businesses or pedestrians
• Hazards of potential equipment failure exposure to walking pedestrians

Features:

• Non-corrosive Stainless Steel Fabrication
• Street Tamper-resistant
• Designed Ascetically for Commercial appeal
• No exposed entry points for external foreign objects
• Long life exhaust fan with thermostat temperature and speed control

Options:

• External control of Exhaust Fan
• Custom UV resistant graphic wraps
• Powder Coat color over stainless material

Designs:

• Pedestal
• Bench
• Custom Available

Advantages of Targeted Fan Ventilation in underground vaults

• The ability to use solid access covers versus open grates
• Engineered force air advantage
• Equipment life extension
• Water and outside solids control, reducing corrosion and equipment damage
• Pedestrian safety