IEC and NEMA/IEEE ratings of current transformers (CTs) in medium voltage applications

First, let’s remind ourselves of the basics in a few sentences. That is something you must know. A current transformer (CT) is designed to produce a secondary current which is… Read more

Jan 20, 2020 | Edvard

Notes in preparation of an MV/LV substation civil drawings and construction layout

MV/LV substations are not only a point of supply but also provide a means of network isolation in the event of faults or emergencies. In that manner, a detailed substation…...

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Dec 05, 2019 | Edvard

Four special connections of current transformers in relay protection applications

As you should already know, current transformers are used for metering and relay protection purposes. When we are talking about current transformers used for metering, their performance is of interest… Read more

Dec 02, 2019 | Edvard

4 electrical quantities you MUST fully understand to select the right cast-resin transformer

This the basic question, but it’s important to start from the scratch. Well, distribution transformers link the MV to the LV system and step down the electrical power to be… Read more

Nov 13, 2019 | Edvard

12 on-site checks to inspect the transformer’s health

On-site inspection of the substation transformer usually exposes important condition changes and it initiates various suspicions that need to be investigated in detail. As with any other substation equipment, many… Read more

Nov 11, 2019 | Edvard

Pre-commissioning checks and tests of high voltage current transformers (CTs)

Once erection is completed, various pre-commissioning checks and tests are performed to ensure the healthiness of the switchyard equipment prior to their energization. This technical article explains various major electrical… Read more

Oct 02, 2019 | Edvard

Testing and commissioning of HV power transformers, circuit breakers, CTs and VTs

As you already know, substations are the points for controlling the supply of power on different routes by means of various equipment such as power transformers, circuit breakers, CTs/VTs, compensating… Read more

Sep 11, 2019 | Edvard

Case study: Failure of a transformer & switchgear buses due to a ferroresonance event

First of all, it’s good to know that the possibility of a transformer ferroresonance condition rapidly increases as the transformer is closer to generator zone. This condition may occur when…...

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Aug 23, 2019 | Edvard

Practical implementation of the six most common transformer protection principles

This technical relies on the previously published article (6 alarms coming from a substation transformer you MUST take very seriously), but is much more dedicated to the implementation of relay… Read more

Jul 24, 2019 | Edvard

6 alarms coming from a substation transformer you MUST take very seriously

Transformers are the most expensive piece of apparatus in a power substation and therefore must have appropriate protection equipment installed to guard against various faults. This technical article explains a… Read more

Jul 22, 2019 | Edvard