This is correct. I work in this field and the grid model is always treated as highly confidential. You can find some models online for some power systems, but often these are simplified or slightly altered to make it no longer representative actual system.
At most with the approach used in the article, you would be able to identify some radially connected regions, or poorly connected areas, but nothing that is a national security risk. To be able to maliciously attack such a system efficiently you'd need an idea of instantaneous flow, component limits, substation topologies and any available mitigating actions.
I don't mean to create the illusion that power systems are impervious to attack. They aren't, and can actually be quite fragile if attacked at the right place and right time. Thankfully the 'arms race' is cyber and not physical. It is easy for grid companies to share best practice on cyber defense, but physical defense and mitigation is very system specific. It is also hard/expensive to defend infrastructure that spans your country or even beyond your border. The Metcalf Sniper Attack is a good example of such a 'difficult to defend against' problem. To perform such an attack you'd need more than a connectivity model.
At most with the approach used in the article, you would be able to identify some radially connected regions, or poorly connected areas, but nothing that is a national security risk. To be able to maliciously attack such a system efficiently you'd need an idea of instantaneous flow, component limits, substation topologies and any available mitigating actions.
I don't mean to create the illusion that power systems are impervious to attack. They aren't, and can actually be quite fragile if attacked at the right place and right time. Thankfully the 'arms race' is cyber and not physical. It is easy for grid companies to share best practice on cyber defense, but physical defense and mitigation is very system specific. It is also hard/expensive to defend infrastructure that spans your country or even beyond your border. The Metcalf Sniper Attack is a good example of such a 'difficult to defend against' problem. To perform such an attack you'd need more than a connectivity model.