Why and where do internal faults happen in substation transformers
Transformers are subjected to many external electrical stresses from both upstream and downstream that can lead directly to internal fault(s). The consequences of any failure can be very great in terms of damage as well as in terms of operating… Read more
Apr 28, 2017 | By Edvard Csanyi
Typical power supply schemes for standby and production generator sets
The main types of prime movers used in engine driven generator sets for industrial sites and commercial buildings are Diesel engines, gas turbines, and steam turbines. Turbines are used mainly for production sets whereas Diesel engines can be used for… Read more
Apr 26, 2017 | By Edvard Csanyi
The most frequent errors in specifying current transformers (CTs)
Current transformers (CTs) form an essential link within the protection chain of electrical networks. Their specification, even if it is handled by specialists, often includes errors and is insufficiently optimized. This often leads to technological impossibilities, operating delays, extra costs,… Read more
Apr 24, 2017 | By Edvard Csanyi
Network harmonics analysis – Installation with 6-pulse rectifier, capacitors & filters
The diagram in figure 1 represents a simplified network comprising a 2,000 kVA six-pulse rectifier, injecting a harmonic current spectrum, and the following equipment which will be considered consecutively in three different calculations. So, let’s list these calculations and start with… Read more
Apr 21, 2017 | By Edvard Csanyi
Rules for dimensioning, disconnecting and protecting the neutral conductor
Dimensioning of neutral conductor Smaller than the cross-sectional area of the phase conductors… Equal to the cross-sectional area of the phase conductors Greater than or equal… Neutral conductor disconnection TN-C system TT or TN-S system IT system Important recommendations #1… Read more
Apr 19, 2017 | By Edvard Csanyi
Thumb rules for surge arrester installation in different earthing systems
A variety of documents deal with the subject of surge arrester installation: for example in France, standard NF C 15-531 focuses on the installation rules of LV surge arresters, and standard NF C 15-100 covers all the LV electrical installations…. Read more
Apr 17, 2017 | By Edvard Csanyi
Circuit breaker selections for low voltage installation (with discrimination)
The LV installation which forms the subject of this study is shown in figure 1 above. This study includes discrimination and coordination of protection between the LV equipment and the protection located upstream of each MV/LV power supply transformer. The… Read more
Apr 14, 2017 | By Edvard Csanyi
Six network operating conditions under which ferroresonance can occur
Due to the multitude of various sources of capacitances and non-linear inductances in a real power network and the wide range of operating conditions, configurations under which ferroresonance can occur are endless. Experience has, however, made it possible to list… Read more
Apr 12, 2017 | By Edvard Csanyi
8 essential relay operating principles of catching faults
In general, as faults (short circuits) occur, currents increase in magnitude, and voltages go down. Besides these magnitude changes of the AC quantities, other changes may occur in one or more of the following parameters: phase angles of current and… Read more
Apr 10, 2017 | By Edvard Csanyi
Three main techniques for mitigating step and touch potential hazards
Mitigating step and touch potential hazards is usually accomplished through one or more of the following three main techniques. Understanding the proper application of discussed techniques is the key to reducing and eliminating any ground potential rise hazards. Contents: Reduction… Read more
Apr 07, 2017 | By Edvard Csanyi
How good are you at reading electrical drawings? Take the quiz.
Every electrician, in every branch of electrical work, will need to consult and understand the information presented on electrical drawings to locate the various outlets, the routing of circuits, the location and size of panelboards, and other similar electrical details…. Read more
Apr 05, 2017 | By Edvard Csanyi
Two main functions of an earth electrode and its installation parameters
The prime function of an earth electrode is the protection of persons. That’s it. It is a fact that we live on Earth! And it is vital to earth exposed metal parts of electrical equipment to avoid electrocution by indirect… Read more
Apr 03, 2017 | By Edvard Csanyi