Electric power industry consulting
Single-core cables are used in both high-voltage and medium-voltage (MV) networks. In both cases, the cables have the same problem – the presence of induced (circulating) currents in solidly bonded screens. To solve the problem, there are other bonding types:👉 Single-point bonding of the screens.👉 Cross-bonding of the screens. Despite the fact that problem with
If a short circuit occurs on the line, the line is switched off. However, what to do next depends on the type of the line:1️⃣ overhead line;2️⃣ cable line;3️⃣ mixed line, having both overhead and cable sections. 1️⃣ OVERHEAD LINEFor an overhead line, up to 60-90% of faults are associated with short-term overlaps of air
Sometimes optic fibre is embedded in power cables. Such a fibre may be located in a metal protective tube among the wires of the screen. The photo shows an example of such a cable, where 4 metal tubes are placed at once, partly to reserve each other (since fibre is very fragile). Why is an
For modern cables of 6-500 kV voltage classes, cross-linked polyethylene (XLPE) insulation is the most common. The properties of XLPE are such that if water molecules penetrate the insulation, they become a source of electric field distortion there, which contributes to the development of insulation defects called “water trees”. The appearance of water inside the