Electric power industry consulting
For high-voltage cable lines, the cross-bonding of screens is quite common. It is used not only for 110-500 kV lines, but also for 6-35 kV. The cross-bonding assumes that the six cable screens (1,2,3,4,5,6) must be removed from the three joints (A,B,C) and then connected to each other in a cross manner using a system
When laying cable lines in the ground, there are several different ways to provide mechanical protection for cables. The following options are known:1️⃣ Covering the cable with bricks on top.2️⃣ Covering the cable with polymer tiles/covers.3️⃣ Laying cable in pipe/duct/conduit.4️⃣ Laying cable in tray/trough.5️⃣ Laying cable in concrete tunnel.Another way of protection is to lay
We often think that 6-35 kV medium-voltage (MV) networks are simpler than 110-500 kV high-voltage (HV) networks. Of course, this is not the case, and it is in MV networks that many serious problems are concentrated – among them, for example, the selection of the optimal method of neutral grounding as well as the selection
Medium voltage 6-35 kV grid usually do not have a solid neutral grounding, and a voltage of 50 Hz may occur on the neutral. Today let’s talk about why it may happen in the cable network even in normal operation, and how this can lead to Temporary Overvoltages (TOV) and damage to equipment. One of
Books seriously explain to the readers where the root of three or the root of two are needed in the energy sector. I decided to write about “combination” of these roots – a cubic root of two. Let it be the “cable root”. Cable specialists know well where and why it is needed. This is
Single-core cables are used in networks of all voltage classes from 6 to 500 kV. Such cables have conductive screens (CU or AL), and these screens are often grounded on both sides. This leads to the appearance of significant longitudinal induced currents (Is) in the screens caused by the 50 Hz magnetic field of the
When any element of the electrical network is energized, a transient process usually occurs. For example, when a voltage is applied to a power transformer, an inrush current of a magnetic nature occurs. The magnitude of the magnetization current of the transformer can reach several kA and sometimes causes serious concern. Today let’s compare inrush
Sometimes it seems to me that the world has gone crazy. At such moments, I think – God, thank you that I have my specialty “power cables”, which on the one hand allows me to distract myself from sad thoughts, and on the other hand to do something really necessary and useful for society. Apparently,
Sometimes it is necessary to have several cables for each phase. For example, this happens when an overhead line (OHL) and a cable line are connected in series (see photos). Or it happens when we connect a transformer of a great power to the busbars (or consumers) using a cable line. Cable connections of overhead
Single-core cables of medium voltage 6-35 kV often have simple grounding of the screens on both sides (“solid bonding”). As a result, the cable screens form closed contours, and the magnetic field of the core current induces currents in these contours, that is screen currents. Induced currents (Is) in the screens pass through the screens