Electric power industry consulting
Today is a short post. It is about the need for thorough control of all stages of the cable line life cycle. And especially for the project and installation. The photo shows a 110 kV cable line, for which the cross-bonding of the screens was to be made according to the project. However, the installation
Very often we see posts where designers and installers share beautiful photos of successfully completed projects. However, then, quietly, in private correspondence, the exploiting organizations share other photos and accompany them with words “What should we do with this?” or “How do we fix this”? In short, many “successful” projects turn out to be “UNsuccessful”
We know that one of the advantages of cables with solid insulation (XLPE, EPR, PVC) is that these cables have no restrictions on the height difference of the route. We can lay such cables horizontally, vertically, at an angle. Any cable arrangement is allowed, as long as the cable bending radius is not violated and
The reliability of cable lines is catastrophically dependent on the quality of installation work. Therefore, we can only be glad that there are a large number of experts all over the world who do their job accurately and precisely. Certainly, some of them may even be called as perfectionists. However, in my opinion, there is
At the ends of the cable line, there are cable terminations. Metallic screens of cables are removed from terminations to the outside, where they are connected in accordance with selected bonding/ grounding scheme. For example, the figure shows the high voltage cable line with one-sided grounding of screens. To have this scheme, metallic screens, with
Earlier, I posted some photos showing that the surge arrester (SA), in case of its damage, can pose a danger to the equipment placed nearby. But what about consequences in case of damage of cable termination or cable joint? There are some examples of what we can get for 110 kV:1️⃣ cable termination mounted in
Look at this example of installing HV cable terminations on the switchgear. In my opinion, there are several mistakes at once. 1️⃣ The lower flange of the termination must be at least 2.5 meters above the ground (this distance is determined by the height of the service personnel who raised his hand up). However, in
The photo shows a concrete underground well. It houses cable joints for 110 kV single-core cables. There are 6 joints for 6 single-core cables, which means that there is a three-phase double-circuit cable line. A fault (short-circuit) occurred in one of joints due to poor-quality installation, which led to an explosive increase in pressure in
1️⃣ As you can see from the photo, the cable screens are grounded directly to the support structure, without the use of link-boxes (I marked screens with yellow lines). This kind of screens connection is not a good solution, because it creates problems for personnel during periodic tests of the cable outer sheath. Let me
The photo shows a 220 kV cable line laid in one of the Central Asian countries. During the construction of the line, cables and couplings (joints and terminations) were used of one of the world famous Asian manufacturers. After several years of operation, the cable joints gave faults one by one, and in total more