Никакая сеть после hyper v перебой в питании

Did you have any other equipment reboot due to the power outage? It almost sounds like there were VLAN tagging settings required for connectivity on a network switch that were lost because no one wrote the running-config to memory.

First make sure that you can access the Hyper-V host. You need to verify that your management interface hasn't been accidentally set to an Internal or Private interface in Hyper-V's Virtual Network Manager. Once you who have successfully verified that you have connectivity to the host you can move on to the VMs.

Verify that your two NICs that are designated for use by your VMs are "External Connections" in Hyper-V's Virtual Network Manager. Make sure the checkbox "Allow management operating system to share this adapter" is also enabled. You should now be able to ping or connect to the IP address for both of these NICs. Then confirm that Virtual Network or Virtual Interface you are connecting to each NIC is added to the appropriate VMs.

I'd just start your network config over from scratch. Verify any vlan settings you might have setup. Reload drivers, re-setup your hyper-v networks. Reset your client vms to the new networks.