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..
Straight forward list of some common motor faults. If I have missed any other common faults, please take a bit of time to add them in as a comment below...
Estimating maximum demand is a topic frequently discussed. Working out how much power to allow for a building can be very subjective . Allowing too much...
If you are working on a large plan, get the real coordinates [latitude, longitude] for two or more points and add them to the drawing. That way you can...
Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...
Famed English chemist and physicist Michael Faraday was born on September 22, 1791, in Newington Butts, a suburb of Surrey just south of the London Bridge...
Request to look at induction motor starting time have come up a few times on the site. Hopefully in this post, I give you guys some idea on how to calculate...
When sizing cables, the heat generated by losses within any sheath or armour need to be evaluated. When significant, it becomes a factor to be considered...
If you want to check a circuit is dead (not live), you should always use the three point method. First check a known live circuit, then check the dead...
In a previous article I looked at the dc resistance of conductors and in this article we turn our attention to ac resistance. If you have not read the...
Capacitors are widely used in electrical engineering for functions such as energy storage, power factor correction, voltage compensation and many others...
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