Monday 4 February 2019

Automating Halley

I am at Halley to oversee the automation project. Due to the uncertain state of the glaciological state of the Brunt Iceshelf, BAS has decided that it is not prudent to winter staff at Halley at the moment. Science continues at and from Halley during the summer months, but in winter only low powered field instruments were able to collect data. We have been working hard to make Halley scientifically productive during the 9 month winter despite having no staff  on site, or any chance of maintenance visits. The key to this is providing reliable mains power at around the 15kW level for the complete 9 months. The route we have decided upon is a micro-jet turbine from a company called Capstone. This has only 1 moving part, the alternator and turbine are on one shaft on air bearings. It has no lubricants or liquid for cooling, and can go for 8000hrs between services - that's more than 9 months. The difficult thing for us is making sure that it maintains it's operating temperature and minimum load, and most importantly that the fuel can get to it without any chance of spillage. Here is the automation platform.
The turbine container is the green one in the middle, the red one is what we call the distribution container which allows us to change all the power connections from  the normal station to the turbine. The white container contains a science experiment, although most of the science experiments powered by the turbine are in their normal locations around the station. Here is the automation platform from the fuel containers.
The two 23000L aviation diesel (Avtur) fuel containers are connected by anti-siphon valves and the levels are monitored so that we know that the amount of fuel that leaves the bulk tanks is the same as finds its way to the day tank.
There are many, many safety measures, and hundreds of parameters that we measure and transmit to Cambridge. Here is the turbine itself.
Here it is in a heat photograph.
Most of the experiments are based around electronic systems and we can control them over the network with very little modification, although some need much more. The white container contains something called a Dobson that measures the ozone above Halley (you may know that Halley found the ozone hole), this requires an operator to twist dials and pull levers and the like. Using servos we have replaced the operator with a computer.





No comments:

Post a Comment