Cables
Sizing of power cables for circuit breaker controlled feeders (part 1)
The following three criteria apply for the sizing of cables for circuit breaker controlled feeders: [fancy_header]I. Short circuit current withstand capacity[/fancy_header] This criteria is applied to determine the minimum cross section area of the cable, so that cable can withstand… Read more
May 10, 2012 | By Asif Eqbal
Energy and Power
Types of Residual Current Devices (RCD)
For domestic applications only the first five of the below listed residual current devices (RCD) need to be considered. For industrial and commercial buildings all of the classifications need to be considered. Table below aims to identify where each type… Read more
May 03, 2012 | By Edvard Csanyi
Energy and Power
Glossary of Medium Voltage Switchgear Terms
This glossary was published originally by Schneider Electric and it is intended to cover the meaning of many common words and phrases used in association with medium voltage switchgear. Many terms will also be applicable to low voltage switchgear as… Read more
Jan 25, 2012 | By Edvard Csanyi
Energy and Power
Anti Pumping And Lockout Relays
What is ANSI code for Antipumping relay? ANSI codes 94 or even 52 can be used. Relays can be divided into six functional categories shown below: Detect defective lines, defective apparatus, or other dangerous or intolerable conditions. These relays generally… Read more
Jan 23, 2012 | By Asif Eqbal
Medium Voltage
ABB MV Switchgear – Single Busbar Or Double Busbar?
Most switchgear installations used in industry with normal service conditions are based on single busbar arrangements. Compared to double busbar switchgear, single busbar switchgear is definitely easier to use, readily understood by operators, requires less space, and the total cost of installation… Read more
Jan 03, 2012 | By Edvard Csanyi
Medium Voltage
Internal arc testing of MV switchgear – IEC 62271-200 (part three)
Continued from: Internal arc testing of MV switchgear – IEC 62271-200 (part two) The following chapter describes the development of a new gas-insulated switchgear generation GHA [4] for primary distribution for internal arc testing according to IEC 62271-200. All tests… Read more
Dec 16, 2011 | By Edvard Csanyi
Energy and Power
Medium voltage circuit breaker operating sequence
Rated switching sequence according to IEC, O – t – CO – t’ – CO. (cf. opposite diagram): O – Represents opening operation CO – Represents closing operation followed immediately by an opening operation Slow: O – 3 min –… Read more
Nov 10, 2011 | By Edvard Csanyi
Energy and Power
Working Principle of Earth Leakage Circuit Breaker (ELCB) and Residual Current Device (RCD)
The operation of an earth leakage circuit breaker (or shorten ELCB) is based on the fact that the algebraic sum of the currents in any healthy single phase, three phase and three phase and neutral system is zero. This simply… Read more
Nov 07, 2011 | By Jignesh Parmar
Maintenance
Retro perspective 30 years ago: Metal-Clad or Metal-Enclosed MV Switchgear? What to choose?
There are two types of switchgear commonly applied today for switching and protection of in-plant medium voltage (4.16 kV through 34.5 kV) power distribution systems. One is metal-clad switchgear using draw-out air-magnetic or vacuum circuit breakers and relays for both load… Read more
Oct 31, 2011 | By Edvard Csanyi
Electrical Lectures
What is the difference between MCB, MCCB, ELCB, and RCCB
This technical article briefly describes the most common breaker-related protection devices in low-voltage applications: MCB, MCCB, ELCB, and RCCB. We’ll describe their main characteristics and limitations and try to solve some misunderstandings and differences that many young engineers mix up…. Read more
Oct 25, 2011 | By Jignesh Parmar
Low Voltage
How Low-Voltage Air Circuit Breaker Works?
A low-voltage circuit breaker is one which is suited for circuits rated at 600 volts or lower. One of the most commonly used low-voltage air circuit breakers is the molded case circuit breaker (picture above). A circuit can be connected… Read more
Oct 23, 2011 | By Edvard Csanyi
Medium Voltage
VISAX – Medium Voltage Metal-clad Switchgear
Wherever electrical power must be distributed and used with maximum availability and reliability, we have the experience and the know-how to offer you the equipment which best meets these needs. To meet today’s demands for quality products, Schneider Electric has… Read more
Oct 17, 2011 | By Edvard Csanyi
High Voltage
Be extremely careful when racking in and racking out circuit breaker
There are many reasons causes arc flash incidents. Some of arc flash explosions occur when substation personnel insert or remove (rack in or out) circuit breakers from low or high voltage switchgear cubicles. Manual racking in and racking out circuit… Read more
Oct 11, 2011 | By Edvard Csanyi
Energy Efficiency
Setting circuit breaker tripping with MS Excel spreadsheet
The protective unit of circuit breaker MUST fulfill: Instantaneous trip setting Im < Iscmin for a circuit-breaker Fusion current Ia < Iscmin for a fuse The protective unit (or device) must satisfy the two conditions: Its fault-current breaking rating must… Read more
Jul 02, 2011 | By Edvard Csanyi
High Voltage
HIS – Highly Integrated Switchgear, Type 8DQ1
No more losing sleep over space restrictions: HIS, the gas-insulated switchgear for indoor and outdoor use requires less than half the space of comparable air-insulated switchgear. The 8DQ1-type HIS is a compact switchgear solution for rated voltages of up to… Read more
Jun 17, 2011 | By Edvard Csanyi
