Its kinda hard to tell what you have from your picture...
Most modern day 30AMP travel trailers will have a 30A Shore Power Cable that will will screw lock in the side of the trailer like this..
The other end of this 30AMP Shore Power Cable that plugs into a standard camp ground pedestal will look like this.
This doesn't really look like what you are showing...
I did find this photo on-line showing which color wires are connected to the trailer side NON screw lock connection. Maybe this will help
Not much help for you I bet... We need more picture I think... or maybe brand and year of TT trailer...
We need a picture of the other end of your cable that plugs into the shore power connection. I'm starting to think you may have only a very old trailer with only 120VAC 20AMP service. The other end of the cable will tell that story for us...
Roy Ken