Electric power industry consulting
Sooner or later, we will make a series of posts about wave processes in cable lines. Understanding these processes allows, for example, to solve the following tasks:1️⃣ Determine the core current when the cable is energized.2️⃣ Determine, for cable lines with single-side grounding of the screens, on which of the two sides it is better
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
Today is a short post. It is about the need for thorough control of all stages of the cable line life cycle. And especially for the project and installation. The photo shows a 110 kV cable line, for which the cross-bonding of the screens was to be made according to the project. However, the installation
The screen (and core) must withstand the short-circuit (fault) current (If), taking into account its time (tf). For XLPE- and EPR-insulated cables, the temperature during a short-circuit should not exceed 250°C. In the lack of information, this temperature is applicable for both the core and the screen. However, according to IEC 61443, if the screen
Modern MV-HV cable has conductive screen. Such screen, after grounding, make it possible to equalize the electric field in the cable insulation and eliminate this field outside the cable. In practice, the question arises – how to choose the screen cross-section? Cable factories have their own opinion. Let’s assume that a screen is made out
Numerous cable lines running next to each other are usually assembled together into so-called pipe blocks. For example, this happens in areas near the switchgear, where up to several dozen parallel lines can be located in one place. Usually, the number of pipes exceeds the number of cables that need to be laid. Such a
If I hadn’t paid only 100 euros in taxes, I would be a criminal. If AC 6-35 kV networks are being massively built all over the world (for example, to connect windfarms to the grid), where each cable line has tens and thousands of euros of useless power losses in screens, then this is called
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