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Finite Volume Simulation: How long does treatment fluid stay in the cable?

December 18, 2010

Q:

How long do the silanes stay in a cable when they are injected? What is the concentration of the resulting siloxanes across the radius of the insulation?

A:

Every single cable is unique. First there are hundreds of possible geometries including different conductor sizes, three different strand compactions, different insulation polymers and thicknesses, jacketed and unjacked, to name a few. On top of that there is the thermal profile of soil in which the cable is buried. The difference between the soil temperature at one meter in depth between Alaska (Cryic soils are light blue in color in the image nearby from the U.S. Department of Agriculture.) and Arizona (Hyperthermic soils are the orange color.) is about 20°C. That 20°C makes a difference of about a factor of three on how fast the fluid permeates from the cable! The cooler temperature in Alaska makes it easier to obtain multi-decade life extension compared to a similar cable buried in the Arizona desert. Finally each cable is loaded differently and hence its operating temperature and temperature profile is entirely unique. In the video, nearby, my collegue describes one of the infinite number of cases to illustrate the general idea. Novinium has done thousands of such simulations in order to arrive at the formulations for its Cablecure 732/733 [Ultrinium] line of products.

Finite Volume Simulation of Cable over 40 years. The cable is an unjacketed 15kV (175 mils of XLPE), a 1/0 concentric stranded conductor buried in mesic soil, and lightly loaded. The method for performing this simulation is protected by U.S. Patents 7,643,977 and 7,848,912. The simulation simultaneously solves the chemical reaction kinetics and the permeation dynamics. The model has demonstrate robust solutions which are within 5% of experimentally measured values.

 

At Novinium we use a patented process (U.S. Patent 7,611,748) to tailor the chemistry to the unique circumstances of each circuit owner and indeed to each cable. No other firm in the world can tailor formulations to optimize performance. Novinium does not ignore the three-fold difference between Arizona and Alaska.