Power systems theory - generation, transmissions and distribution
Many questions sent in to the site are in connection with motor starting and in particular star-delta. For all but the simplest application, there is merit in performing a more detailed study.&... read more..
Traditionally substations have used circuit breakers, current transformers (CT), voltage transformers (VT) and protection relays all wired together using copper cables. With advances in digital... read more..
Modelica is an open source (free) software language for modelling complex systems. Having never used it before, I thought I would download a development platform and see how it stacked up. This... read more..
Within Europe the European Committee for Electrotechnical Standardization (CENELEC) has standardised the both the designation and colour of cables. These are published in CENELEC document... read more..
A UPS is an uninterruptible power supply. It is a device which maintains a continuous supply of electrical power, even in the event of failure of the mains (utility) supply. A UPS is inst... read more..
Power cables can basically be classified into earthed and unearthed cables, where earthed and unearthed refer to the application for which the cable is used. Earthed system refers to a three phase syste... read more..
Photovoltaic (PV) cells (sometimes called solar cells) convert solar energy into electrical energy. Every year more and more PV systems are installed. With this growing application, it's ... read more..
Fire resistant and fire retardant cable sheaths are design to resist combustion and limit the propagation of flames. Low smokes cables have a sheath designed to limit the amount of smoke and toxic ha... read more..
Capacitors have numerous applications in electrical and electronic applications. This note examines the use of capacitors to store electrical energy. The sidebar shows details of a typical c... read more..
If two dissimilar metals are touching and an external conducting path exists, corrosion of one the metals can take place. Moisture or other materials acting as an electrolyte between the metals... read more..
While not as popular as it once was, frame leakage protection does still have some use in some circumstances. In essence frame leakage is an earth fault type protection. A current transfo... read more..
Ever wondered what kind of power an aircraft uses when parked at the airport stand.
Normally the aircraft generates it own power, but when parked with the engines switched off power provided ... read more..
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...
Tapping your forearm or hand with a finger could soon be the way you interact with gadgets. A new technology created by Microsoft and Carnegie Mellon ...
A fundamental concept behind the operation of alternating current systems is that voltage and current waveforms will be sinusoidal – a Sine Wave. This...
The new standard IEC 61439 replaces the old 60439. Compared to the old standard, the new 61439 is a more clearly defined and takes into account the assembly...
For unbalance conditions the calculation of fault currents is more complex. One method of dealing with this is symmetrical components. Using symmetrical...
MIT OpenCourseWare, makes the materials used in teaching all MIT subjects available on the Web, free of charge, to any user in the world.
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...
While there are a vast array of cable insulation materials, these are often divided into two general types; Thermoplastic or Thermosetting. For example...
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...
Laplace transforms and their inverse are a mathematical technique which allows us to solve differential equations, by primarily using algebraic methods...
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