The original soviet electrical power distribution systems were designed with redundancy. All electrical power consumers were divided into 3 categories:
First category was assigned to consumers where power interruption may lead to loss of life, loss of very important production, damage to important industrial equipment and processes (line nuclear reactors).
Second category was assigned to places like hospitals, electric public transportation, industrial processes where power interruption will cause loss of production etc.
Third category was assigned to public housing and commercial consumers where power interruption can be allowed.
All 1st and 2nd category consumers were supplied with a redundant power feeds. Dual power lines and dual transformers were supplying power to those consumers. Dual power lines and transformers were installed on the supply side. Power lines and transformers were designed to only carry half the normal maximum current. If anything happens of one side of the supply, the second side will simply be loaded to it's full designed power carrying capacity thus providing redundancy and uninterrupted electrical power supply. Third category was only limited to a single supply line and a single power transformer feeds (non-redundant).
I once briefly worked at large factory in Central Russia, as a requirement for my summer practice at the university. I once asked the chief engineer if they have experienced any power failures. His answer was - "It never happened in the 40 years this plant has been in operation".
I'm sure, nowadays they have a lot more automation and computer controlled power distribution systems. I'd be surprised if they don't have a redundant system to bypass all computer controlled automation to keep the power going to consumers.
Also, Russian infrastructure doesn't rely on computers and internet as heavily as the US infrastructure. The heavy redundancy mentality goes back to the Soviet days where redundancy was more important than installation and maintenance costs.