Electric power industry consulting
For cables there are many reasons for water penetration and growing of water trees inside the insulation. For example, it could be: 1️⃣ Production:👉 the raw materials used were not dried;👉 on the extrusion line (application of insulation or polymer sheath), when starting a new order or completing it, the water level in the cooling
Let us continue green posts. Today we’ll talk about how much the voltage on the equipment may differ from the voltage on the surge arrester (SA). To do this, consider a lighting wave coming from the overhead line (OHL) to switchgear. After passing the SA site, the wave decreases its magnitude to the level of
When designing cable lines, we use software to check ampacity, taking into account the key influencing factors:✅ cross-section of cable elements;✅ the mutual arrangement of phases and circuits;✅ screens’ bonding type;✅ laying conditions;✅ environmental parameters. It turns out that almost every software known in the cable industry calculates ampacity perfectly, and also helps with calculating
We all see here on the Internet (LinkedIn etc) the unspoken competition between different manufacturers of subsea cables. These companies build concrete towers in which the process of applying insulation to the cable core takes place. They always mention the height of the tower, and every new tower is more and more high. It looks
When XLPE was advertised to us, it was always said that dielectric constant of XLPE (2.4) is noticeable less than that of paper impregnated insulation (4.2). Hence, we had the impression that the capacitance of modern cables (XLPE) would less than that of the previous generation of cables (paper). Accordingly, this means that after switching
In medium voltage networks of 6-35 kV, at least the following methods of laying single-core cables in the ground are known:1️⃣ Directly in the ground;2️⃣ In the ground in a common pipe;3️⃣ In three different pipes arranged in a bundle. In 110-500 kV high voltage networks, option 2️⃣ is missing, and only options 1️⃣ and
Before putting the cable line into operation (and then periodically during operation), the integrity of the outer sheath of cables should be checked. The procedure consists of the following steps:1️⃣ Disconnect the line from the network (if it was in operation).2️⃣ Disconnect the SVLs from the link boxes.3️⃣ Unground cable screens at both sides of
Some companies like to talk about successful projects, and we know that there are really a lot of such projects, and this is very important for our industry. However, successful projects do not teach us much, and, in fact, it is much more interesting to study the mistakes that were made during the realization of
Let us continue with a series of green posts on transients and surge arresters. Today let us assume that, in three-phase network, a single-phase-to-ground fault occurs, in phase A. In this case, the 50 Hz voltage on the two undamaged phases B and C will increase compared to its normal value. Compared to normal operation,
For medium voltage (MV) line, usually, screens of single-core cables are grounded at both sides. Let us assume that we have two separate MV lines, differing in the mutual arrangement of three single-core cables:Line 1️⃣ – trefoil;Line 2️⃣ – in row. In the conditions of the example, according to the book, we get the following