A power outage affects both the server at your home and the travel router at the remote location.
When the power goes out
The VPN server router loses power, terminating the VPN tunnel.
Internet access through the VPN travel router is cut due to the Internet kill switch.
When the power comes back
The VPN server router restarts automatically.
The VPN tunnel is re-established if there are no lingering issues with your home ISP.
Configuration
No data is lost or corrupted during the power outage.
The system is designed to handle power failures gracefully.