Electrical Lectures
Dielectric Strength Of Insulator Materials
The atoms in insulating materials have very tightly-bound electrons, resisting free electron flow very well. However, insulators cannot resist indefinite amounts of voltage. With enough voltage applied, any insulating material will eventually succumb to the electrical ”pressure” and electron flow… Read more
Jun 14, 2012 | By Edvard Csanyi
Energy and Power
MCB – Miniature Circuit Breaker Construction
The miniature circuit breaker (MCB) plays an important role in providing overcurrent protection and a disconnect means in electrical networks. Recent advancements in circuit breaker technology has increased breaker performance and protection. A breaker is a device designed to isolate a circuit… Read more
Jun 07, 2012 | By Edvard Csanyi
Electrical Lectures
Fundamental Characteristics of Circuit Breaker
The fundamental characteristics of a circuit breaker are: Its rated voltage Ue Its rated current In Its tripping current level adjustment ranges for overload protection (Ir or Irth) and for short circuit protection (Im) Current-level setting values which refer to the… Read more
Jun 05, 2012 | By Edvard Csanyi
Energy and Power
Understanding Vector Group of Transformer (Part 2)
Vector Groups are the IEC method of categorizing the primary and secondary winding configurations of 3-phase transformers. Windings can be connected as delta, star, or interconnected-star (zigzag). Winding polarity is also important, since reversing the connections across a set of… Read more
Jun 04, 2012 | By Jignesh Parmar
Electrical Lectures
Understanding Vector Group of Transformer (Part 1)
Three phase transformer consists of three sets of primary windings, one for each phase, and three sets of secondary windings wound on the same iron core. The vector group of the transformer is determined by the connection between the windings… Read more
Jun 03, 2012 | By Jignesh Parmar
Energy and Power
Process Design Basics for Station Facility
The purpose of this article is to establish the design basis electrical system Front End Engineering Design (FEED) and data design or standards uses in the gathering stations facility will be built. Electrical system design refers to the process flow diagram… Read more
May 25, 2012 | By ivan.kurniawan
Energy and Power
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 taps or load tap changers, are sources of difficulties in… Read more
May 19, 2012 | By Edvard Csanyi
Cables
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 keep the voltage drop (due to impedance of cable conductor)… Read more
May 17, 2012 | By Asif Eqbal
Electrical Lectures
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 figures obtained with meters. What is needed is an instrument… Read more
May 15, 2012 | By Edvard Csanyi
Energy and Power
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 voltage metering devices. There are three primary applications for which… Read more
May 14, 2012 | By Edvard Csanyi
Cables
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 current continuously at the designed ambient temperature and laying condition. Ampacity… Read more
May 13, 2012 | By Asif Eqbal
Energy and Power
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 caused by a direct stroke. An insulator string can also… Read more
May 08, 2012 | By Edvard Csanyi
Energy and Power
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 Code prohibits AC and DC in the same box. You’ll need two… Read more
May 05, 2012 | By Edvard Csanyi
Energy and Power
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 be considered. Table below aims to identify where each type… Read more
May 03, 2012 | By Edvard Csanyi
Energy and Power
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 perform either on-delay or off-delay timing. An arrow is used… Read more
Apr 30, 2012 | By Edvard Csanyi
