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Project: T183700 #30/126

Part A

Transformers generate heat, and a critical operating parameter is their cooling capacity. There are a number of cooling fluids used for this purpose, but the most common is mineral oil. But regardless of the type, release of this oil is undesirable for multiple reasons. One is the environmental impact, which may be significant, especially when the oil makes its way into waterways or other public receptors.

Containment is an important mechanism for controlling oil spills from transformers and can aid in fire protection by removing the oil from heat sources. Sizing of the containment will include multiple considerations, including total oil volume, firefighting water demands and precipitation.

This report summarizes research on current environmental codes and regulations, new technologies for containment and EPM’s history of transformer fires in the nuclear industry to guide containment volume calculations and examines existing studies and guidelines available to the public. This report is provided in association with Report 30/126B for Transformer Fire Protection.


Transformer, Oil, Containment, Spill, Spill Management, spill model, EPA, biodegradability

Part B

The protection of substation assets is vital to ensuring both reliable distribution of power and protection of adjacent structures/properties. A combination of fire prevention and fire protection is used to address fire and explosion failures. The goal of fire prevention is to limit the likelihood of the occurrence of fire. The goal of fire protection is to mitigate the effects of fire and limit the damage from fires that do occur.

Fire prevention methods are commonly employed to reduce the likelihood of fires/explosions involving transformers and related electrical equipment. Such methods include monitoring the transformer oil and components for early signs of degradation, limiting ignition sources and combustibles, maintaining equipment, venting and oil/fluid selection, and oil/fluid containment.

There are also a number of fire protection methods commonly employed to mitigate the effects of fire originating from the transformer equipment to protect buildings, adjacent equipment, or adjacent properties. Fire protection is dependent on the proper application of various systems, including fire detection, gaseous firefighting agents, water mist systems, sprinkler systems, water spray systems, firewalls, oil/fluid selection, and oil/fluid containment.

Fire prevention and protection methods may vary based on the location of the substation. Substations in more densely populated areas require a higher level of protection to mitigate fire hazard to adjacent structures. Substations located in wildland interface areas will require different methods of fire prevention and protection to areas adjacent to wildfire and contamination. Transformers located in populated areas or inside buildings, on the other hand, will include provisions to protect adjacent buildings and people.

This report documents the advantages and disadvantages of these fire prevention and protection features, provides guidance for best practices, and discusses the latest transformer protection advancements and technologies. The goal is to provide the reader with an understanding of available options and the ability to assess which would be best suited for their application.


Transmission, Substation, Transformer, Fire Protection, Best Practices, Water Spray, Firewall, Water Mist