3.8 Cyber Security Issues Affecting Distribution

3.8.5 Resilience and Cyber Security

In the energy sector, two key phrases are becoming the focus of international and national policies: “grid resilience” and “cyber security of the cyber-physical grid”. Grid resilience responds to the overarching concern: "The critical infrastructure, the Smart Electric Grid, must be resilient - to be protected against both physical and cyber problems when possible, but also to cope with and recover from the inevitable disruptive event, no matter what the cause of that problem is - cyber, physical, malicious, or inadvertent."

“Grid resilience … includes hardening, advanced capabilities, and recovery/reconstitution. Although most attention is placed on best practices for hardening, resilience strategies must also consider options to improve grid flexibility and control.”   Resilience of the grid is often associated with making the grid able to withstand and recover from severe weather and other physical events, but resilience should also include the ability of the cyber-physical grid to withstand and recover from malicious and inadvertent cyber events.

Resilience, sometimes defined as “the fast recovery with continued operations from any type of disruption” can be applied to the power system critical infrastructure. A resilient power system is designed and operated not only to prevent and withstand malicious attacks and inadvertent failures, but also to detect, assess, cope with, recover from, and eventually analyze such attacks and failures in a timely manner while continuing to respond to any additional threats.

The “cyber-physical grid” implies that the power system consists of both cyber and physical assets that are tightly intertwined. Both the cyber assets and the physical assets must be protected in order for the grid to be resilient. But protection of these assets is not enough: these cyber and physical assets must also be used in combination to cope with and recover from both cyber and physical attacks into order to truly improve the Resilience of the power system infrastructure.

All too often, cyber security experts concentrate only on traditional “IT cyber security” for protecting the cyber assets, without focusing on the overall resilience of the physical systems. At the same time, power system experts concentrate only on traditional “power system security” based on the engineering design and operational strategies that keep the physical and electrical assets safe and functioning correctly, without focusing on the security of the cyber assets. However, the two must be combined: resilience of the overall cyber-physical system must include tightly entwined cyber security technologies and physical asset engineering and operations, combined with risk management to ensure appropriate levels of mitigation strategies.

As an example, distributed energy resources (DER) systems are cyber-physical systems that are increasingly being interconnected to the distribution power system to provide energy and ancillary services. However, distribution power systems were not originally designed to handle these dispersed sources of generation, while DER systems are generally not under direct utility management or under the security policies and procedures of the utilities. Many DER systems provide energy from renewable sources, which are not reliably available at all times. Therefore, the resilience of power systems to even typical disruptions is increasingly at risk as more of these DER systems are interconnected.

Although arguably the resilience of individual DER systems can be seen as less important than the resilience of a single large bulk power generator, in fact the combined resilience of aggregations of large numbers of even small DER systems can ultimately be more critical than a single bulk generator in the overall resilience of the power system.