Its part of our "Bürokratendeutsch" (bureaucracy German) culture. In German bureaucracy and Law, everthing relevant needs to be defined by one particular, unique word. And this word has to be used in Laws, decrees and official letters to be legally effective. So if a new technology needs regulation, some german dork probably needs to invent a new word for it. For example: "Motorized Scooter" is officially called "Elektrokleinstfahrzeug" (electronical small(est) vehicle) instead of the im German commonly used word "E-Scooter" So especially for the technology sector a whole bunch of words gets created that nobody uses or know. Sometimes this words are so speciallized or uncommon, that even google/bing/ecosia/what ever doesnt know them.

So long story short: this word above is the official word, but most technicians working on it will just call it "Umspannungsanlage" or "Trafo".

Fun fact: 2/3 of the native German speaking population doesnt understand standard letters from local authorities, so some authority offices ad explanation letters in common german to the official, legally effective ones. Its called "Einfachdeutsch" (simple German)