device to connect smaller cabled to bigger capacity cables

I would like a device that is sort of like your circuit breaker but is more a small device you can put between smaller capacity cables and your or the built in higher capacity cables and it limits the draw from the lower capacity cable to 95% of the max capacity of the weakest cable connected to it.

What i would like to do is setup multi power generation of wind and solar etc on lower capacity cables for each farm but enough to handle what they can generate and then have a way to connect that to a main backbone unlimited cable to make to go to the distributor you make and charge it at the rate of the power generated from all the sources combined vs the one with the smallest cable.

People may also want to use it the other way as well to take power from the bigger cable into a smaller cable without loosing all the data signals and it being huge like a transformer would be for this sized power cables