Physical Security Threats to the Transmission and Distribution Grid, Part 2

Both physical and cyber security threats to the electric utility transmission and distribution (T&D) grid in all regions of the world are real. Part 1 of this blog series discussed the physical security problem and some of the measures North American utilities are taking to respond to the North American Electric Reliability Corporation (NERC) CIP-14 requirements. Regardless of whether replacement high-voltage transformers, switchgear, and breakers need to be ordered from major vendors such as ABB, General Electric (GE), Siemens, or other regional companies, replacement equipment is not warehoused. Instead, it must be special ordered, manufactured, and shipped to the transmission substation where the replacement will be made.

Manufacturing lead times are typically 12 to 18 months, which is an issue the North American transmission system operators are dealing with by participating in Grid Assurance, banding together to create stockpiles of critical equipment in multiple locations across the nation. And while Grid Assurance will own and provide timely access to an inventory of emergency spare transmission equipment, the regional or national shipping and transportation issues are daunting.

Issues of Size

The sheer size of 250 kV to 750 kV high-voltage transformers makes physical transportation a logistical nightmare, regardless of whether large-scale trucks or railroad transportation is used. Companies such as ABB and Siemens have highly specialized trucks and flatbed rail cars dedicated to high-voltage transformer transportation. A huge flatbed truck designed to transport from 100 tons to 500 tons of high-voltage transformers can be seen below. These trucks need to be routed over roads that are certified for heavy loads and often have circuitous routes because of height and width clearance issues.

Transformer Shipping Using Lowboy Flatbed Truck

(Source: ABB)

However, the largest 500 kV and 750 kV extra high-voltage transformers may require specialized rail transport with similar clearance issues, bridge weight restrictions, and even access close to the transmission substation. Shipping and transportation from regional sites, vendor manufacturing centers, or overseas shipping yards may take weeks or even months, again lengthening the restoration timeframe. Moving huge transformers by rail has a similar set of constraints, based on the vicinity of rail lines to the transmission substation location.

Unfortunately, extra high-voltage and high-voltage transformers are huge pieces of equipment, and replacement and restoration time following a physical attack or transformer failure is not an overnight event. It could take months for parts to be manufactured, delivered and installed. It is clear that restoration initiatives are intimidating. A series of restoration examples will be provided in Part 3 of the Physical Security blog series.