Why the semi conductor layers are used in the 132KV cables?

At that voltage corona is a big problem. Corona is a low current discharge through the air which causes power loss. It is hard to control by simply insulating the wire. A highly resistive layer, however, will cause the voltage to drop gradually from the core to the outside of the layer. That way, at least the voltage of the surface exposed to air or other layers of insulator is kept low, minimizing corona losses. I'm pretty sure that's what it's for, anyway.