Power systems theory - generation, transmissions and distribution
Photovoltaic (PV) systems are typically more efficient when connected in parallel with a main power gird. During periods when the PV system generates energy this can be utilized and the grid energy u... read more..
Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base. By removing the impact of varying voltages, the... read more..
For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical components, the unbalance system is broken dow... read more..
In the previous note we looked at the approach taken by the standard to the sizing of cables and illustrated this with an example. We then looked at one method of applying the standard and iden... read more..
Current transformers (CTs) are used to convert high level currents to a sma... read more..
IEC 60287 "Calculation of the continuous current rating of cables (100% load factor)" is the International Standard which defines the procedures and equations to be used in determining the ... read more..
The image (reproduced from IEC 60909) shows a typical fault in an ac system. From the illustration it can seen that there is an initial dc component (id.c.). This initial dc compo... read more..
One of the fundamental requirements of an alternating current distribution systems it to have the ability to change the magnitude of voltages. It is more efficient to transmit power at high voltag... read more..
I've recently come across this question a couple times browsing the internet. Decided to give a quick answer here. A rectifier transformer is a transformer which includes diodes or thyristors in the sam... read more..
Over the past year or so I've been involved in on going discussions related to referring fault levels from the secondary of a transformer to the primary side. While this is easy for some people to... read more..
Electromagnetic compatibility (EMC) is the study of coordinating electromagnetic fields give off equipment, with the withstand (compatibility) of other equipment within the vicinity. In it's simplest... read more..
Installation of a UPS can help in reducing problems due to issues with the power supply. A lot of people relate this to nine key issues. Depending on the type of UPS installed it is possible... read more..
The standard aims to consolidate AC and traction voltages within the industry and defines the following bands: band 1 - A.C. systems 100 V to 1...
One of the comments on my Motor Starting Series was asking for something on duty cycles. Here it is. As a purchaser of a motor, you have responsibility...
Everything physical in electrical engineering from insulations to conductors revolves around materials. Here we are listing common materials along with...
Following on from my post on railway electrification voltages, I thought an introduction to traction substations would be a good idea. Traction substations...
When current flows within a wire, a magnetic field is created. The potion of this magnetic field perpendicular to the wire is called the magnetic flux...
If your are ever called out to troubleshoot something on your electrical system, one of the first things consider is the supply voltage. You want to ensure...
Light Emitting Diodes (LED ) are increasing gaining favour in both the domestic and commercial sectors; due to their efficiency, sustainability and durability...
If two dissimilar metals are touching and an external conducting path exists, corrosion of one the metals can take place. Moisture or other materials...
The image (reproduced from IEC 60909) shows a typical fault in an ac system. From the illustration it can seen that there is an initial dc component ...
For the past few years I have reading eBooks on my HTC touch phone. On and off I have debated buying an eReader and recently purchased a Sony PRS-300 ...
If you have some expert knowledge or experience, why not consider sharing this with our community.
By writing an electrical note, you will be educating our users and at the same time promoting your expertise within the engineering community.
To get started and understand our policy, you can read our How to Write an Electrical Note.