Energy and Power
How to get rid off the harmonics in electrical system?
The subject of harmonics is also a contributory factor in electrical noise I already wrote few days ago (Cable spacing as a means of noise mitigation). It also causes several other problems in power circuit components such as motors, transformers and capacitor… Read more
Jul 16, 2014 | By Edvard Csanyi
Electric Motor
13 features and advances of using electronic soft starters for a motor starting
Soft starters serve for a continuous adjustment of the starting characteristic of three-phase asynchronous motors to the requirements of the load by controlling the voltage across the motor and enable for an optimum integration of the drives in process control… Read more
Jul 14, 2014 | By Edvard Csanyi
Cables
Cable spacing as a means of noise mitigation
In situations where there are a large number of cables varying in voltage and current levels, the IEEE 518-1982 standard has developed a useful set of tables indicating separation distances for the various classes of cables. There are four classification… Read more
Jul 11, 2014 | By Edvard Csanyi
Medium Voltage
Microprocessor and conventional secondary systems compared
Secondary systems are all those facilities needed to ensure reliable operation of the primary system, e.g. a high voltage substation. They cover the functions of controlling, interlocking, signalling and monitoring, measuring, counting, recording and protecting. With conventional secondary systems, the… Read more
Jul 09, 2014 | By Edvard Csanyi
Energy and Power
Harmonic distortion and high frequency applications
The presence of harmonic frequencies in addition to the fundamental 50Hz, bring about distortion of the fundamental sine wave. Considerable problems may arise dependant upon the level of this distortion. Sources of harmonic distortion can be: Variable Speed Drives UPS… Read more
Jul 07, 2014 | By Edvard Csanyi
Energy and Power
How the Weather Affects Conductors
Notice how a conductor is strung between poles. It is not pulled tight; it sags. In hot weather it sags even more than in cold weather. Consider the analogy of the clothesline. A tightly strung clothesline as shown in Figure… Read more
Jul 04, 2014 | By Edvard Csanyi
Protection
Protection Against Overexcitation Of a Transformer
Overexcitation of a transformer means that the magnetic flux in the core is increased above the normal design level. This will cause an increase of the magnetizing current and the transformer can be damaged if this situation isn’t taken care… Read more
Jul 02, 2014 | By Edvard Csanyi
Cables
An example how to calculate voltage drop and size of electrical cable
According to the National Electrical Code, in order for general use circuits to operate reasonably efficiently, the maximum voltage drop for branch circuit conductors is 3% and for feeder and branch circuit conductors combined it is 5%. When designing circuits… Read more
Jun 30, 2014 | By Jignesh Parmar
Safety
How dangerous are induced currents in transmission towers and poles?
Landowners and developers should be aware of the potential for nuisance and startle shocks (caused by induced voltage) that can occur when someone comes in contact with a large conductive object (eg. a vehicle, building or even fencing) located on or off… Read more
Jun 27, 2014 | By Edvard Csanyi
Electrical Lectures
2 Most Common Contributing Factors In Motor Insulation Failure
The most frequent failure in electrical equipment is the degradation and breakdown (flashover) of the insulation. Electrical insulation can be liquid or solid, organic or inorganic. Organic insulation material consists of: enamels, varnishes, resins, or polymers that are applied to the steel surface to provide… Read more
Jun 25, 2014 | By Edvard Csanyi
Power Substation
Arriving at the scene of a substation fire. What should you do first?
Power substations contain transformers, large quantities of oil, energized electrical equipment and, in some cases, cylinders of compressed gas. Some of the oil may contain polychlorinated biphenyls (PCBs). On arriving at a substation fire, normally you should first call for firefighters… Read more
Jun 23, 2014 | By Edvard Csanyi
Energy and Power
Differences between disconnectors, load switches, switch disconnectors and circuit breakers
Various types of devices are available for carrying out the switching and protection tasks listed under a title that are specially designed to fulfill the respective requirements. The various parts of IEC 60947 (Low voltage switchgear and controlgear) specify the… Read more
Jun 20, 2014 | By Edvard Csanyi
Electric Motor
Selecting AC induction motors for cement plant applications
This technical article relies on the great paper written by Barton J. Sauer (Siemens Energy & Automation) which goes into essence of selecting the proper AC motor for cement plant applications. Although motors may appear to be the least complicated component… Read more
Jun 18, 2014 | By Edvard Csanyi
Power Substation
Why is continuous on-line monitoring of partial discharge in the switchgear necessary?
Not sure? You know that periodical maintenance test like partial discharge test can still leave switchgear in virtually unknown condition. Insulation defects and deterioration may very well develop in service within maintenance cycle. These defects are often not detectable with… Read more
Jun 16, 2014 | By Edvard Csanyi
Transformers
An Example Of Transformer Tap-Changer Correct Adjustment
A 13800V/4160 V transformer has five taps on the primary winding giving -5%, -2 1/2 %, nominal, +2 1/2 % and +5 % turns. If, on-load, the secondary voltage reduces to 4050 V then, which tap, should be used to… Read more
Jun 13, 2014 | By Edvard Csanyi
