Energy and Power
Transient Voltage Surge Suppressors
Transient Voltage Surge Suppressor (TVSS) is a device that every data center or mission critical facility should have. Why should every data center have one and what does it do… Read more
Dec 01, 2011 | By Edvard Csanyi
Protection
Transformer and Transformer-Feeder Protection
The development of modern power systems has been reflected in the advances in transformer design. This has resulted in a wide range of transformers with sizes ranging from a few… Read more
Nov 30, 2011 | By Edvard Csanyi
Energy and Power
Overvoltages Caused by Direct Lightning Strokes
A lightning stroke is defined as a direct stroke if it hits either the tower or the shield wire or the phase conductor. This is illustrated in Figure 1. When… Read more
Nov 29, 2011 | By Edvard Csanyi
Protection
Transformer Winding Faults
A fault on a transformer winding is controlled in magnitude by the following factors: Source impedance Neutral earthing impedance Transformer leakage reactance Fault voltage Winding connection Several distinct cases arise… Read more
Nov 02, 2011 | By Edvard Csanyi
Protection
Short circuit protection of generator’s stator windings by overcurrent relays
If current transformers are not connected in the neutral ends of wye-connected generator windings, or if only the outgoing leads are brought out, protective devices can be actuated, as in… Read more
Oct 24, 2011 | By Edvard Csanyi
Power Substation
Complete overview of lightning arresters (part 3)
Continued from article Complete overview of lightning arresters (part 2) There are several types of lightning arresters in general use. They differ only in constructional details but operate on the… Read more
Oct 08, 2011 | By jiguparmar
Power Substation
Complete overview of lightning arresters (part 2)
Continued from article Complete overview of lightning arresters (part 1) Surge arresters are devices that help prevent damage to apparatus due to high voltages. The arrester provides a low-impedance path… Read more
Sep 29, 2011 | By jiguparmar
Power Substation
Complete overview of lightning arresters (1)
Lightning can create voltage surges in several of the following ways. Lightning can score a direct hit on your house. It can strike the overhead power line which enters your… Read more
Sep 23, 2011 | By jiguparmar
Power Substation
Animal deterrents and security in substation
The vast majority of electrical utility substations designed to transform transmission voltages to distribution class voltages employ an open-air design. The configurations may vary, but usually consist of equipment that… Read more
Sep 05, 2011 | By Edvard Csanyi
Protection
Bus protection – Overcurrent differential
When selecting relays for bus protection, a major concern is the ability of the protective relaying scheme to restrain from tripping for close-in line faults. Tripping for bus faults, the… Read more
Aug 31, 2011 | By Edvard Csanyi
Energy and Power
Surge arrester types and auxiliary equipment
Nearly 100 years ago, electrode gaps (rod, sphere, or pipe) were used to limit overvoltages on equipment (Sakshaug, 1991). Some of these systems, particularly pipe gaps, may still be in… Read more
Aug 25, 2011 | By Edvard Csanyi
High Voltage
Capacitor protection by surge arresters – ABB
Generally speaking, capacitor protection by surge arresters has been a difficult task before ZnO arresters became available. The high discharge currents and possible energies associated with an arrester operation at… Read more
Aug 22, 2011 | By Edvard Csanyi
Energy and Power
Applications and forms of differential relays
Differential relays take a variety of forms, depending on the equipment they protect. The definition of such a relay is “one that operates when the vector difference of two or… Read more
Aug 15, 2011 | By Edvard Csanyi
Energy and Power
Whole-House Protection Strategy
No single SPD (Surge Protection Strategy) can protect all the equipment in a residence from all causes of electrical surges. Instead, a whole-house protection strategy, consisting of point-of-entry and point-of-use… Read more
Aug 13, 2011 | By Edvard Csanyi
Low Voltage
How residual current device (RCD) works?
The residual current device (rcd) is used to detect earth fault currents and to interrupt supply if an earth current flows. The main application is to prevent electrocution but RCDs… Read more
Jun 11, 2011 | By Edvard Csanyi
