Special considerations when selecting transformer protection
Current transformer ratio selection and performance require special attention when applying transformer protection. Unique factors associated with transformers, including its winding ratios, magnetizing inrush current, and the presence of winding… Read more
May 19, 2012 | By Edvard Csanyi
Sizing of power cables for circuit breaker controlled feeders (part 3)
Continued from article Sizing of power cables for circuit breaker controlled feeders (part 2) This criterion is applied so that the cross sectional area of the cable is sufficient to… Read more
May 17, 2012 | By Asif Eqbal
Power Measurement In AC Circuits
Power measurement in AC circuits can be quite a bit more complex than with DC circuits for the simple reason that phase shift complicates the matter beyond multiplying voltage by current… Read more
May 15, 2012 | By Edvard Csanyi
Introduction to instrument transformers
Instrument transformers (ITs) are designed to transform voltage of current from the high values in the transmission and distribution systems to the low values that can be utilized by low… Read more
May 14, 2012 | By Edvard Csanyi
Sizing of power cables for circuit breaker controlled feeders (part 2)
Continued from article Sizing of power cables for circuit breaker controlled feeders (part 1) This criterion is applied so that cross section of the cable can carry the required load… Read more
May 13, 2012 | By Asif Eqbal
Overvoltages Caused by Indirect Lightning Strokes
A direct stroke is defined as a lightning stroke when it hits a shield wire, a tower, or a phase conductor. An insulator string is stressed by very high voltages… Read more
May 08, 2012 | By Edvard Csanyi
Using AC and DC together in electrical system?
There are a number of issues to using AC and DC together in the same electrical system. Briefly, they are: circuit boxes and hardware, outlets, wiring schemes and sizes, and switches. The Electrical… Read more
May 05, 2012 | By Edvard Csanyi
Types of Residual Current Devices (RCD)
For domestic applications only the first five of the below listed residual current devices (RCD) need to be considered. For industrial and commercial buildings all of the classifications need to… Read more
May 03, 2012 | By Edvard Csanyi
Time relays setting ranges explained in details
Time relays are used in control switching operations involving time delay. Most of these time relays have multiple time setting ranges and most of them are explained below. Time relays… Read more
Apr 30, 2012 | By Edvard Csanyi
Overview Of Electrical Loads In Building
The electrical design professional should determine a building’s electrical load characteristics early in the preliminary design stage of the building to select the proper power distribution system and equipment having… Read more
Apr 27, 2012 | By Edvard Csanyi
System protection and safety coordination definitions
The objective of system protection is to detect faults and to selectively isolate faulted parts of the system. It must also permit short clearance times to limit the fault power… Read more
Apr 16, 2012 | By Edvard Csanyi
Inspection Of Voltage Drop In Conductors
It is part of the inspection process to ensure that installed conductors have been correctly selected for current carrying capacity and voltage drop. To check the suitability of the current… Read more
Apr 15, 2012 | By Edvard Csanyi
What is incident energy caused by arc flash?
Incident energy is the energy per unit area received on a surface located a working distance away from the arc flash location. The working distance is the distance from where… Read more
Apr 13, 2012 | By Edvard Csanyi
Key Cyber Security Purposes for the Smart Grid
In the Smart Grid, there are two key purposes for cyber security: Keep electricity flowing to customers, businesses, and industry. For decades, the power system industry has been developing extensive… Read more
Apr 12, 2012 | By Edvard Csanyi
Short review of resistance, reactance and impedance
Resistance is essentially friction against the motion of electrons. It is present in all conductors to some extent (except superconductors!), most notably in resistors. When alternating current goes through a… Read more
Apr 08, 2012 | By Edvard Csanyi