The Ninth Day

You missed the updates for the last 2 days! What!? you can start a thread now??! I can do whatever you can do. Okay, this is going to be.. troublesome. Anyway, that is what weekends are for! To do things that you aren't able to do on the weekdays! Nonsense. Whatever. Note to self: Do not baring2 kejap before updating the blog. Back to cables. Remember XLPE cable from the last entry? This is how it looks like:

The white thing surrounding the copper conductor is the XLPE material. Why XLPE is more preferable? It has high electrical and mechanical strength, high aging resistance, environmental stress resistance, anti-chemical corrosion, easy to be constructed, and can withstand higher temperature. XLPE is so cool! I know, right.

But then again, XLPE cable are also prone to failures. 2 types of common failures are partial discharge which I have briefly covered and water tree. A tree made from water? Wrong. It is a diffuse structure in the XLPE resembling the shape of a tree and is formed and grow in the presence of moisture, impurities, and electric field over time. In The Lab, this is how they investigate water trees in cables:

The XLPE insulator is first separated from the cable and put into the green machine to be sliced. The sliced XLPE will be put in a water bath at a certain temperature, together with a colouring substance to make the water tree more visible, if there's any. Credit goes to The Colleague for the information. After that, it will be cut into pieces before being observed by using a microscope.

Observation in action!

The picture in the red box above is taken from somewhere without permission. Hahaha. Not funny. It shows 2 types of water tree. Water tree is fatal because once they are big enough, they will bridge the insulation system, causing the cable to fail as shown by 'leakage tree'. The pictures in this entry is actually taken on The Eighth Day but since there's nothing eventful that happened in this day, I just need to put something, heh.

Moving on to the tenth day!