I am reading an application guide related to high-voltage DC and have come across a symbol that I do not recognize:
The source of the schematic is this document from Siemens.
Based on the context, my guess is that it might be either some sort of adjustable or controllable element, like a contactor or adjustable reactor, but I am not sure.
If you look further in the publication, you will find that it is a smoothing reactor.
In skimming through the document, I didn't see an explicit statement about the reactor being adjustable, but they did mention something about them being constructed with a number of "partial turns." They do say that the capacitor banks are tuned.
