Liquid Nitrogen to the rescue: How to fix a 230kV oil filled electricity cable.

This is still one of my favourite mad engineering stories on the web. How to fix a 230kV oil filled electricity cable with Liquid Nitrogen.

It turns out they have a problem with an underground wire. Not just any wire but a 230 KV, many-hundred-amp, 10 mile long coax cable. It shorted out. (Lotta watts!) It feeds (fed) power from the Scattergood Steam Plant in El Segundo to a distribution center near Bundy and S.M. Blvd.

To complicate matters the cable consists of a copper center conductor living inside a 16 inch diameter pipe filled with a pressurized oil dielectric. Hundreds of thousands of gallons live in the entire length of pipe. Finding the fault was hard enough. But having found it they still have a serious problem. They can’t afford to drain the whole pipeline – the old oil (contaminated by temporary storage) would have to be disposed of and replaced with new (pure) stuff which they claim takes months to order (in that volume). The cost of oil replacement would be gigantic given that it is special stuff. They also claimed the down time is costing the costing LA $13,000 per hour. How to fix it and fast?

That’s where the LN-2 comes in. An elegant solution if you ask me. They dig holes on both sides (20-30 feet each way) of the fault, wrap the pipe with giant (asbestos-looking) blankets filled with all kind of tubes and wires, feed LN-2 through the tubes, and *freeze* the oil. Viola! Programmable plugs! The faulty section is drained, sliced, the bad stuff removed, replaced, welded back together, topped off, and the plugs are thawed. I was amazed.

Source: engineering pornography

NASA Deep Space Network

View of the Canberra Complex showing the 70m (230 ft.) antenna and the 34m (110 ft.) antennas. The Canberra Deep Space Communications Complex, located outside Canberra, Australia, is one of the three complexes which comprise NASA’s Deep Space Network. Credit: Nasa

The Deep Space Network, or DSN, is much more than a collection of big antennas. It is a powerful system for commanding, tracking and monitoring the health and safety of spacecraft at many distant planetary locales. About – Deep Space Network

Voyager 2 fun facts:

  • Data rates upto 115.2 kilobits at Jupiter.
  • I huge 64 kilobytes of tape backed storage, and 70 kilobytes program memory.
  • Built in 1970s – expected to keep transmitting to 2025 (The RTG is now degrading).
  • Software built on Fortran and COBOL.
  • In flight software updates made in 1990.

What Is the Oldest Computer Program Still in Use?
Why NASA Needs a Programmer Fluent In 60-Year-Old Languages
Radioisotope Thermoelectric Generator (RTG)
Wiki: NASA Deep Space Network
Wiki: Voyager 2
See current activities on DSN.