Electric power industry
Traditionally, the concept of “transposition” was used mainly for overhead lines (OHL) with a voltage of 330 kV and higher. For OHLs, the concept of “transposition” means a periodic change in the relative position of the three phase wires ABC. However, the situation has changed after the appearance of single-core cables with XLPE-insulation – the
Faults on cable terminations (as well as cable joints) are a significant problem of cable lines. Termination fault also means that a section of cable inside and near the termination may be damaged too. Therefore, for the installation of a new termination instead of broken one, not only new termination itself is required, but also
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
Among all the programs for modeling processes in electrical networks, one of the most common is EMTP (ATP, ATP-EMTP). A huge amount of research is carried out using EMTP, and this is clearly seen by the number of mentions of EMTP in various publications. Such success of the EMTP became possible due to the fact
Do you hear the operator breathing strangely? As if it’s hard for him to breathe? That’s right! That’s because he’s wearing a gas mask. Otherwise, he may die, because he went down into the cable collector, where there was a great fire the day before. As you can see from this video, a lot of
Counters of the impulse number were used for the previous generation of MOA – it was gapped valve-type arresters. That generation had a concept of “resource” for them because of a small thermal resource of nonlinear elements connected in series with gap. It was only 20-30 discharges of the gap, after which it was necessary
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
When using single-core 6-500 kV cables, various grounding schemes of screens are known. However, regardless of the scheme, it is recommended to connect cable screens to the ground at the ends of the line using special boxes. They are useful for personnel safety and convenience of testing the outer sheath of single-core cables. There are
Under the 50 Hz AC operating voltage there is a AC current inside the MOA. For a serviceable MOA, it is about 0.5 mA (some models can have up to 1 mA). If the current increases, then this is the basis for checking the MOA – this is the reasoning of those who lobby for