HV/MV/LV Transformer Protection Schemes
Transformer protection should take into account the power, voltage, vector group and the importance of the unit within a particular system. Depending on these factors, the transformers can be assigned… Read more
Nov 28, 2015 | By Edvard Csanyi
Connection Schemes For Testing Insulation Resistance Of Electrical Equipment
The following schemes show how to connect a Megger insulation tester to various types of electrical equipment. The schemes also show in principle how equipment must be disconnected from other circuits before… Read more
Nov 11, 2015 | By Edvard Csanyi
Electrical installations where use of TN-C-S system is prohibited
A real danger can arise when the non-current-carrying metalwork of an installation is connected to the system’s neutral, as is the case with a TN-C-S-fed system. The ground system is… Read more
Nov 06, 2015 | By Edvard Csanyi
6 steps to establish electrically safe work condition
Equipment that has been deenergized and verified as such is said to be in an electrically safe work condition. Article 120.1 of NFPA 70E outlines six steps that must be… Read more
Oct 31, 2015 | By Edvard Csanyi
9 basic rules for dimensioning of electric circuits
Basically, the dimensioning process itself is easy to understand and can be performed using simple means. Its complexity lies in the procurement of the technical data on products and systems,… Read more
Oct 16, 2015 | By Edvard Csanyi
6 Voltages a Person Can Be Exposed To In a Substation
Figures 1 and 2 show the voltages a person can be exposed to in a substation. There are many definitions related to these voltages, but the following six are the… Read more
Oct 09, 2015 | By Edvard Csanyi
Substation DC Auxiliary Supply – Battery And Charger Applications
A power substation can have one or several DC systems. Factors affecting the number of systems are the need for more than one voltage level and the need for duplicating… Read more
Sep 21, 2015 | By Edvard Csanyi
SF6 or Vacuum MV Circuit Breaker In Specific Switching Applications
Many years of experience in developing both SF6 and vacuum medium-voltage circuit breakers has yielded up ample evidence that neither of the two technologies is generally better than the other,… Read more
Sep 14, 2015 | By Edvard Csanyi
The Basics of Electrical Bus Protections
When we examine electrical protection schemes, the best place to start is with electrical bus protections, as they are the easiest to protect. They utilize the fundamental concept of the overcurrent relay (Figure 1)…. Read more
Sep 05, 2015 | By Edvard Csanyi
Electrical Design Project Of a Small Bakery
A small bakery with just a counter and storage areas is simple to design. The electrical design follows the layout for a house, but care must be taken on loading factors if… Read more
Aug 26, 2015 | By Edvard Csanyi
Few advice for improving integrity of protective conductor
Most modern electronic equipment uses switched mode power supplies (SMPS) which draw pulses of current from the mains supply rather than a continuous sinusoidal current. The fast rise time edges of the… Read more
Aug 14, 2015 | By Edvard Csanyi
7 key steps in lighting design process
To achieve the best overall outcome in a lighting installation, it is important to avoid the tendency of rushing straight into luminaire selection before determining more broadly what is required… Read more
Aug 03, 2015 | By Edvard Csanyi
Essential Basics of Total Harmonic Distortion (THD)
For a signal y, the total harmonic distortion (THD) is defined by the equation: This definition complies with that of standard IEC 61000-2-2. Note that the resulting value may exceed… Read more
Jul 22, 2015 | By Edvard Csanyi
Differences in size and weight of equipment using copper and aluminium conductors
It is a common misconception that electrical equipment built using aluminum conductors will always be larger than the same equipment using copper conductors. While the actual conductor within the equipment… Read more
Jul 13, 2015 | By Edvard Csanyi
Maintenance of electrical equipment in buildings
Apart from safety, maintenance is needed to keep plant in an acceptable condition. Maintenance of this kind must be reviewed on an economic and energy efficiency basis. While it is… Read more
Jul 08, 2015 | By Edvard Csanyi