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
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
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
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
High Voltage
How to mitigate effects of very fast transients (VFT) on HV equipment
The level reached by very fast transients (VFT) overvoltages originated by disconnector switching or line-to-ground faults inside a gas insulated switchgear (GIS) are below the basic insulation level (BIL) of substation and external equipment. However, aging of the insulation of… Read more
Jun 11, 2014 | By Edvard Csanyi
Energy and Power
6 Factors Influencing Requirements for a Good Grounding System
In an industrial plant or other facility that requires a grounding system, one or more of the following must be carefully considered (refer to Figure 1 below): Limiting to definite values the voltage to earth of the entire electrical system…. Read more
Jun 06, 2014 | By Edvard Csanyi
Energy and Power
Which type of residual current device (RCD) to use and when?
We know how (very) important the total earth loop impedance Zs is in the reduction of shock risk. However, in TT systems where the mass of earth is part of the fault path, the maximum values of Zs given in… Read more
Apr 09, 2014 | By Edvard Csanyi
Energy and Power
Erection of earthing arrangements (TNC, TN-S, TNC-S, TT)
The earthing arrangements (TNC, TN-S, TNC-S, TT) of low voltage networks is largely determined by the Low Voltage Supplies. However, if the incoming supplies are at 11kV and the transformers are in the ownership of the user, the LV supplies… Read more
Apr 07, 2014 | By Edvard Csanyi
Energy and Power
Practical calculations of lightning strikes frequency
We distinguish between the following frequencies of lightning strikes which can be relevant for a building or structure: ND – Frequency of direct lightning strikes to the building or structure;· NM – Frequency of close lightning strikes with electromagnetic effects;… Read more
Nov 04, 2013 | By Edvard Csanyi
Energy and Power
What’s Really Important When You’re Designing The Low Voltage Switchgear?
Here what’s important when you’re designing the low voltage switchgear: Device Application in the Supply Circuit Short-circuit strength Release (Trip Unit) Device Application in Supply Circuits (Coupling) Device Application in the Distribution Circuit Device Application in the Final Circuit The… Read more
Oct 07, 2013 | By Edvard Csanyi
Electrical Lectures
What Is a Good Ground Resistance Value?
The goal in ground resistance (or earth resistance) is to achieve the lowest ground resistance value possible, that makes sense economically and physically, when contacting the earth, also known as the soil/ground rod interface. Ideally, a ground should be zero… Read more
Oct 02, 2013 | By Edvard Csanyi
Energy and Power
Comparison Of Neutral Earthing Methods
Neutral earthing systems are very similar to circuit breakers in that they do nothing until something in the system goes wrong! There are several methods for system earthing which can be generally divided into three main categories: Insulated earthing, Solid… Read more
Sep 16, 2013 | By Edvard Csanyi
Energy and Power
Lightning And Surge Protection For Cable Networks And Antennas For TV (Part 2)
Continued from part one: Lightning And Surge Protection For Cable Networks And Antennas For TV (Part 1) If an antenna is protected by isolated air-termination systems it means: – That in the area of flat roofs an air-termination rod will be… Read more
Sep 13, 2013 | By Edvard Csanyi
Energy and Power
Lightning And Surge Protection For Cable Networks And Antennas For TV (Part 1)
IEC 60728-11 complies with the state of the art and offers easy, standardized and effective protective mechanisms against the effects of lightning strikes into antennas. Antennas installed according to this standard do not increase the probability of lightnings to strike… Read more
Sep 09, 2013 | By Edvard Csanyi
