How optical communication cables work and how they differ from other cables

In several previous articles I mentioned optical fibre in the context of substation automation, protection signaling, communication between electrical devices, LAN communications, etc. Now I will get into details of… Read more

May 23, 2018 | Edvard

Overhead vs. Underground Residential Distribution Circuits. Which One Is ‘Better’?

This debate continues. Both designs have advantages (see Table 1). The major advantage of overhead circuits is cost. An underground circuit typically costs anywhere from 1 to 2.5 times the… Read more

Nov 13, 2017 | Edvard

Sizing calculations for 20/3.3 kV, 12.5 MVA transformer feeder cable

Typical calculations for a 20kV transformer feeder cable are presented below. After correct cable voltage classification the following considerations apply: Current carrying capacity Short circuit rating Voltage drop Earth loop… Read more

May 08, 2017 | Edvard

Guidelines for high potential (Hi-Pot) DC testing of medium voltage cables

This technical article provides general guidelines for high potential “Hi-Pot” DC testing of MV power cables. All tests made following cable installation and during the warranty period must be performed… Read more

Feb 20, 2017 | Edvard

Specifying energy efficient motor, cabling and local power transformer

Many energy saving actions can encourage specifiers and engineers to look closely at the savings which can be made by specifying an energy efficient version of a particular component. The… Read more

Jan 09, 2017 | Edvard

5 key factors to the correct cable selection and application

It is essential to know cable construction, characteristics, and ratings to understand problems related to cable systems. However, to correctly select a cable system and assure its satisfactory operation, additional… Read more

Oct 31, 2016 | Edvard

Shielding and Grounding Practices for Control Cables in EHV Substations

For several years, the increased application of solid-state devices for protective relaying and control and for electronic equipment, such as audio tones, carrier and microwave equipment, event recorders, and supervisory… Read more

May 20, 2016 | Edvard

Recommended Practice For Cableways Selection and Installation

The term cableways refers to conductors and/or cables together with the means of support and protection, etc. for example: cable trays, ladders, ducts, trenches, and so on… are all cableways…. Read more

Mar 14, 2016 | Edvard

Underground residential distribution – More hidden and more reliable

A classic underground residential distribution circuit is an underground circuit in a loop arrangement fed at each end from an overhead circuit (see Figure 1). The loop arrangement allows utilities… Read more

Mar 11, 2016 | Edvard

8 tips to avoid ground loops when dealing with signal level circuits

General recommendation is to properly design and implement the facility’s grounding system to avoid unwanted involvement of ground loops with the operation of the equipment. This kind of approach can… Read more

Jan 06, 2016 | Edvard

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