As of my last knowledge update in September 2021, the concept of "total owning cost" is not a commonly recognized term in the context of transformers. It's possible that this term has emerged or gained prominence after my last update, or it could be a term specific to a certain industry or domain that I'm not aware of.
In a general context, "total owning cost" typically refers to the complete cost associated with owning and operating a particular asset, product, or resource over its entire lifecycle. This includes not only the initial acquisition cost but also ongoing expenses such as maintenance, operation, repairs, upgrades, and any other costs incurred throughout its useful life.
If you could provide more context or details about how "total owning cost" specifically relates to transformers or any specific industry, I'd be happy to help you understand the concept better based on the information available up to September 2021.