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Wide Area Grid Security


Sometime things are just destined to happen. I was doing some research for a paper posted some time ago. The paper involved potential alternatives to functions that emitted greenhouse gases, and I came across some large drones our military had commissioned that used liquid hydrogen for fuel. I thought that these might be an evolutionary step to commercial aircraft that used the same fuel. I finally decided this was a bridge too far, and found an alternative. Since I'm a data junkie, I never toss any information, so I gathered up all my research materials on drones and filed them away.

A few weeks later one of my friends at Energy Central emailed and said in November they were focusing on how drones could be used for utility incident reports, and did I have any ideas about this subject?. My mind started working on this. What if all transmission and distribution lines (substations, etc.) were able to be observed a high percentage of the time? Then most of the time "incidents" could be observed in realtime. There might be a way to do this. Read on.


There are two classes of large drones (hereafter unmanned aerial vehicles or UAVs). I briefly looked and one class: medium-altitude, long-endurance (MALE) UAVs. These fly up to about 30,000 ft. and can remain airborne for up to four days. I discounted these fairly quickly due to concerns about collisions with civil or commercial aviation while on station and poor operation in bad weather.

The other class is high-altitude, long-endurance (HALE) UAVs. These have a ceiling of over 50,000 ft. which would put them well above all commercial (and civil) air traffic and most weather.

So this paper will explore HALE UAVs that might possibly be used for grid security. The subsections below describe existing designs for these UAVs.

2.1.Global Hawk

This is UAV is probably at the top of my list. It has been flying for 20 years and in service for 15 years. It has been used extensively by the military, has amassed more than 200,000 flight hours with missions flown in support of military operations. However its creator (Northrop Grumman) has newer UAVs, and may be looking for opportunities in non-military roles. Global Hawk has been used for civilian missions, and Northrop Grumman may be interested in a surveillance-as-a-service model.

The Global Hawk has a ceiling of 60,000 feet, and a mission duration of up to 35 hours. This UAV has a really nice website (link below) with many resources, including the nice picture below, and a really, really good video on top of the home page.

2.2.Airbus Zephyr

Per the Zephyr's web site:

Zephyr is a High Altitude Pseudo-Satellite (HAPS) that fills a capability gap between satellites and UAVs:

  • Zephyr is the world's leading, solar-electric, stratospheric UAV
  • It will revolutionize defense, humanitarian and environmental missions all over the world

The Zephyr also has a nice website (linked below) with lots of resources, including nice flyer from which I stole the image below. Their nice videos are through the second link below (click on "Videos" in the upper right corner after the site and scroll finish. I would recommend "Zephyr, never stop exploring.".

Two models are currently being offered, the Zephyr S (Bottom) and Zephyr T. Both are extremely light and powered by solar cells plus battery-storage. The Zephyr cruses at about 65,000 feet. Per the brochure:

Airbus’ technology. Zephyr holds 3 World records including the endurance record of 14 days – which is several times longer than any other UAV…

Zephyr provides continuous surveillance, communications and monitoring services across areas of tens of thousands of square kilometers. Airbus has developed proven high resolution imaging and high bandwidth communication services and is developing ever more capable payloads to further improve the range and value of services available.

2.3.Other Potential Designs

A number of military firms have created promising prototype designs that were mothballed. At least a couple of these occasionally either get trotted out with a new design wrinkle or result in an enhanced development program. The two worth mentioning are:

Boeing's Phantom Eye HALE UAV:

AeroVironment's Global Observer:

3.Surveillance and Business Models

The remaining question is, how do we get the HALE UAV's capabilities in a position to monitor the grid full-time? The solution is probably not to have a utility buy a fleet of UAVs, rather a surveillance-as-a service (SAS) model is suggested. This has several strong advantages:

  • Partnerships are much more likely to facilitate this security capability. Over a large area occupied by any large utility there will probably multiple utility and other organizations that will be interested in investing a reasonable amount in having a 24 x 7 surveillance capability. For instance, in Northern to Central California this might include PG&E, CAISO, many other utilities in this area, communication companies and CalFire.
  • The most advanced multispectral surveillance capabilities will only come with a SAS model. Most of these capabilities were developed under defense contracts that preclude their use in the public domain, but the defense contractors that own these systems are used to providing SAS services to non-defense clients.
  • This capability will be very expensive. Thus the partnerships suggested above (to spread the expense), and the SAS model to keep the costs under control are probably keys to its viability.
  • This capability could have tremendous future profitability for the winning contractor. Once this model has proven its value in one area, it can be easily extended to other areas. For instance the area and team suggested in the first bullet could be extended to large utility service areas in Nevada, Arizona, Washington / Oregon, Idaho, Colorado, etc.

4.Further Reading

In 2007 NASA Published an extensive analysis of all HALE UAV designs. Even though this document is over 10 years old, the science behind these designs is current. For anyone wishing to explore these craft further, I would strongly recommend this excellent document (linked below).

John Benson's picture

Thank John for the Post!

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Audra Drazga's picture
Audra Drazga on Nov 9, 2018 5:35 pm GMT

Great Photos John!  Thanks for the contribution! 

John Benson's picture
John Benson on Nov 9, 2018 11:20 pm GMT

Thanks for the positive comments, Audra.

Be sure to see the video on the Global Hawk home page (linked in the paper), if you already haven't. It's really good.

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