From the category archives: Power Systems

Power systems theory - generation, transmissions and distribution

Lightning Protection and Earth Electrode Resistance

By Steven McFadyen on 11/22/2009 7:48 PM

Most installations involve some form of lightning protection system which is connected to an earth electrode.  The function of the earth electrode is to dissipate the lightning strike safely in to ... read more..


1,000 kV UHV First for China

By Steven McFadyen on 11/3/2009 8:33 PM

At the beginning of the year China put the world's first 1,000 kV UHV transmission system into operation. Transmitting power at over a million volts is just amazing.  Some key facts about the syste... read more..


Gas Insulated or Air Insulated Switchgear

By Steven McFadyen on 8/11/2009 2:32 AM

Various arguments exist around SF6 Gas Insulated (GIS) and Air Insulated (AIS) medium voltage switchgear. Recently we had to change a GIS design to AIS due to an instruction from&nbs... read more..


Voltage Levels – Confused?

By Steven McFadyen on 3/23/2009 2:06 AM

I was having a conversation the other day about voltage levels.  While everyone was in agreement that low voltage was 1000 V and less, there was more confusion on the terms 'Medium Voltage' and ... read more..


Three Phase Current - Simple Calculation

By Steven McFadyen on 3/1/2009 11:47 AM

The calculation of current in a three phase system has been brought up on our site feedback and is a discussion I seem to get involved in every now and again. While some colleagues prefer to remember... read more..


Aluminium Windings - Dry Type Transformers

By Steven McFadyen on 2/25/2009 3:19 AM

The other day I was talking to a colleague who is a building services consultant.  Despite regularly specifying dry-type/cast resin transformers he was unaware that many manufactures’ use alu... read more..


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Mobile Phones (Brick to Implant)

The mobile phone was born in 1973. They were the size of a brick and weighed a couple of kg, making them difficult to fit into your pocket. At a few thousand...

IEC Reference Designations

The IEC publishes a series of documents and rules governing the preparation of documents, drawings and the referencing of equipment.   Depending on country...

Voltage Drop in Installations - Concepts

Problems on achieving maximum voltage drop within an installation come up often. Depending where you live, local regulations will have different limits...

Alternating Current Circuits

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...

Closed Doors

"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong...

Fault Calculations - Introduction

Fault calculations are one of the most common types of calculation carried out during the design and analysis of electrical systems. These calculations...

The ac resistance of conductors

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...

IEC Document Designation

Often document control is dictated by project requirements, for example a particular organisation may have an existing numbering system. Existing company...

Lightning Protection and Earth Electrode Resistance

Most installations involve some form of lightning protection system which is connected to an earth electrode.  The function of the earth electrode is to...

Fault Calculation - Symmetrical Components

For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...

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