Electric power industry consulting
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
There are cable lines, there are overhead lines. However, there are also mixed lines consisting of both cable and overhead sections. On such mixed lines, the question arises as to how best to equip a transition point. There are a lot of issues there:➡️ where to place the set of cable terminations and of which
Let us discuss the length of the bonding cable and also such a thing as the steepness of current/voltage impulses that creates voltage drop. Industry documents suppose that the voltage in the joint can be determined as a sum of residual voltage of SVL (sheath voltage limiter) and the voltage drop across the bonding cable,
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