Power systems theory - generation, transmissions and distribution
There are a lot of interesting two page type notes on various medium voltage topics – switchgear, circuit breakers, bus systems etc. It is on the Siemens US site, so many of he note are IEEE/ANSI ... read more..
Following on from my post on railway electrification voltages, I thought an introduction to traction substation... read more..
This post is quick introduction and overview to different railway electrification voltages used in answer to a question sent in via email. While there are numerous voltages in use through out the w... read more..
This is the first of two posts on the resistance of conductors. In the next post I will look at the ac resistance, including skin effect and we deal with this. To get started, this post will look at the... read more..
A quick post in connection with an email question:
Live Tank - the circuit breaker the switching unit is located in an insulator bushing which is live at line voltage (or some voltage above g... read more..
The correct sizing of current transformers is required to ensure satisfactory operation of measuring instruments and protection relays. Several methods exist to size current transformers. This note will... read more..
Electrical engineering has a multitude of laws and theorems. It is fair to say the Ohm's Law is one of the more widely known; it not the most known. Developed in 1827 by Georg Ohm the law defines the re... read more..
This morning I was explaining how differential protection works to a junior engineer. To give him something to read I opened up the NPAG (Network Protection and Automation Guide, by Areva) and turned to... read more..
While there are a vast array of cable insulation materials, these are often divided into two general types; Thermoplastic or Thermosetting. For example the current capacity determination of a cable in a... read more..
When selecting a generator, there are inherent limits on the active and reactive power which can be delivered. Generators are normally sized for a certain kW at a power factor of 0.8. However, to unders... read more..
I received this question by email a few weeks. First thoughts was that it is a product of the mathematics of rotating a straight conductor in a magnetic field. While I guess this is the primary issue... read more..
If you are wondering what happened to our cable notes, the short answer is that we have moved them to myCableEngineering.com. The "Knowledge Base" at...
Coils of wire on the rotor carry a d.c. current which generates a magnetic field. A stator magnetic field is created using either permanent magnets or...
A recurring theme on our forums is cable sizing. Now many installations are unique and require special consideration. However, a lot of the time things...
Electromagnetic compatibility (EMC) is the study of coordinating electromagnetic fields give off equipment, with the withstand (compatibility) of other...
The widely used United Sates standard ANSI/IEEE C37.2 'Electrical Power System Device Function Numbers, Acronyms, and Contact Designations' deals with...
Variable frequency drives are widely used to control the speed of ac motors. This note looks at the mechanisms which enable drive units to control the...
Gauss's Electrical law defines the relation between charge ("Positive" & "Negative") and electric field. The law was initially formulated by Carl Friedrich...
Alternating current (a.c.) is the backbone of modern electrical power distribution. In this article I’ll be pulling some of the more important concepts...
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...
Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is...
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