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 has always been obvious to me that in terms of thickness, there are two types of outer sheath of high voltage (HV) and extra-high voltage (EHV) cables:✅ Ordinary sheath – it has a thickness of about 5 mm.✅ Reinforced sheath – it has a thickness of about 6-7 mm.However, when I started trying to
To design the cable line, we need to pass the following stages:✅ Evaluate the electrical strength of the cable outer sheath (jacket) and agree on what is the permissible voltage on the screen.✅ Select the grounding/bonding scheme of the screens (number of sections, cycles, etc.)✅ Perform the thermal calculation of the cable line and select
There are projects where reserve cables or reserve pipes/ducts are provided (empty or with a cable in them). Of course, this complicates the project and makes it more expensive, but maybe it’s worth it? It looks like we are talking about “insuring” a cable line in case of trouble, but the problem is that even
We all know that to build an extended cable line, we have to replace HVAC technology with HVDC technology. However, where does one get the value of the length of the line, after which the transition to HVDC can no longer be avoided? It turns out that this length can be determined by calculation, and
Cable is like a child – it’s not enough to give birth to him at the “factory”, but he must also be given to the right “school” with good “teachers”. Let’s take a closer look at the “graduation” of our cable. The photo shows the set of 110 kV cables and their terminations, and I’m
Single-core cables of 6-35 kV usually have a two-side grounding of the screens (“solid bonding”). This leads to the fact that in normal operation, the magnetic field of the core induces 50 Hz currents in the screens. At a given current in the core, the induced currents in the screens depend on:✅the cross-section of the
Last week in LinkedIn, I came across a post where the cable was “preheated” with an open fire before laying. Workers “heated up” beautiful cable with open fire and at the same time cheerfully said, “How good that we have a cable with a non-flammable outer sheath”. I couldn’t get past such a terrible attitude