Power System Security - Some Hard Facts

Tony Sleva | Mar 10, 2003

How do you evaluate the robustness of extra high voltage substations and transmission lines to attack by disenfranchised individuals, determined terrorists, hostile employees, knowledgeable intruders, and common thieves? How do you quantify the reduction in the risk as improvements are made and newer designs are developed? What changes are cost effective? These are some of the first questions that come to mind when power system security improvements are considered.

What is more important: substation visibility, perimeter security, intrusion detection, access roads, component design and placement, structural design, redundancy, or power system topography? SEA Consulting Services utilizes a methodology that rates substations on a scale of 0 to 200 (the higher the score, the greater the risk) and transmission lines on a scale of 0 to 100. Most substations we evaluate rate in the range of 90 to 140 points. These ratings would be expected as almost all substations were built before September 11, 2001. After low cost, easy to install modifications are implemented, substation risk ratings typically can be reduced to around 70, an improvement that, we feel, justifies the expense.

How much does it cost to reduce the risk of sabotage to an acceptable level? Our surveys indicate that substation security can be substantially enhanced for less than 2% of the replacement cost of an extra high voltage substation and that new substations, designed with security in mind, would only cost 10% more than existing substation designs. Admittedly, retrofitting an existing station can be much more expensive if the substation is located in a high visibility area such as near highway overpass, but in general, retrofitting substations to reduce risks to acceptable levels does not need to be terribly expensive.

In the future, electric power facilities should be designed with reduced visibility and they should be designed to withstand anything short of direct military action. Several utilities, in Florida and Nevada, have already constructed substations that significantly reduce visibility and thereby reduce the risk of the substation becoming a target of disenfranchised individuals. (Although these stations were designed to meet local zoning requirements, they are good examples of things that can be incorporated into electric power system designs when visibility is a design consideration.)

What are some of the things that need to be incorporated into new substation designs? First, all new substations should be low profile facilities that are transparent to passersby. Visibility of new substations can be reduced if barrier walls replace chain link fences; if overhead lines are terminated at points that are remote from substations (the first mile of each line should be underground cable); if substation sites are excavated to reduce the apparent height of structures; and if substations are not built in highly visible locations. Substation survivability, if a substation is attacked, could be enhanced by placing barriers between redundant components and by hardening access to control cabinets, control cables, and other components located throughout the yard.

At existing substations, the focus should be on changes that enhance survivability. This includes barriers to reduce visibility, focused intrusion detection and component hardening. The goal should be to assure that when an intruder is detected, security personnel could respond before an intruder, who has a good understanding of substation component design, can damage redundant components.

If you are working to reduce the vulnerability and improve the resiliency of the electric power system, SEA congratulates you. If you think nothing can be done to reduce the vulnerability of electric power facilities or that the cost to reduce vulnerability is excessive, compare the cost of facilities to the cost of possible security enhancements. We recognize that completely eliminating security risks is impractical, but enhancing security to reduce the risk to tolerable levels is doable and justifiable.

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