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..
When making adding a Note to our site we have a great online WYSIWYG editor and things are pretty simple. However, if you prefer you can write, manage...
Per unit fault calculations is a method whereby system impedances and quantities are normalised across different voltage levels to a common base. By removing...
In an earlier note on the site [Photovoltaic (PV) - Electrical Calculations], the theory of solar (PV) cell calculations was introduced. In particular...
Battery powered cars are a hot topic and widely debated. The pros, cons, issues and time frames can be talked about endlessly. An article by the Telegraph...
IEC 61439 'Low-voltage switchgear and controlgear assemblies', specifies standard arrangements of switchboard (call forms of internal separation). The...
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...
Current transformers (CTs) are used to convert high level currents to a smaller more reasonable level for use as inputs to protection relays and metering...
Light Emitting Diodes (LED ) are increasing gaining favour in both the domestic and commercial sectors; due to their efficiency, sustainability and durability...
Some colleagues had an issue earlier in the week on sizing conduits to be cast in concrete for some power cables . It became clear that none of us had...
Often document control is dictated by project requirements, for example a particular organisation may have an existing numbering system. Existing company...
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