Electric power industry consulting
The calculation of cable pulling forces is one of important section of the design documentation. It assumes at least the following calculations:✅ cable pulling forces (should be no more than 30 N/mm2 for a cable with an aluminium core and no more than 50 N/mm2 for a cable with a copper core);✅ pressure on the
In 6-35 kV network, suppose we have busbars ABC, with two lines, and a ground fault has occurred in phase A of a line (1). In case of isolated neutral, the ground fault current (Igf) is determined by the EMF (Ea) and the capacitances of all network to the ground, and therefore it is a
HVDC projects can be very roughly divided into two types:1 – subsea;2 – underground.The former ones are practically hidden from us, and all we see is a cable laying vessel on the surface of the water. The second ones are more open, have many photos, which I propose to discuss today (only for the purpose
It is believed that “we cannot have a closed contour of magnetic material around an AC single-core cable”. However, in practice, there are issues with the application of such a rule. For example, would the following contours be dangerous?➡️ it does not tightly cover the cable, but has large transverse dimensions;➡️ it has a side
When applying insulation, it is necessary to keep the high voltage cable in an upright position for a certain time to avoid ovalization and other negative effects. If we know the recommended time, then we understand that the required height of the extrusion tower will be proportional to the desired cable production speed. Hence the
Cable couplings are one of the places where cable line damage often occurs. There are many different types of couplings, but most of them can be classified into one of two categories:✅ Cable terminations;✅ Cable joints. Cable terminations are placed above the ground and can be subjected to periodic inspection, which is a good thing.
Today we will not talk about alcohol (“bar”), but about a conductive element called:✅ equipotential bar (bar, bus);✅ earth continuity conductor (ECC). Questions arise:1️⃣ why do we need such a bar;2️⃣ how to provide equal distances from the bar to all phases A,B,C;3️⃣ how to calculate the optimal bar material and cross section (Fb). Unfortunately,
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