Energy and Power
Short-Circuit Switching Capacity Definition
The switching capacity is the r.m.s value of a current at a given power factor cosφ as well as a given rated voltage at which a switchgear or a fuse can still shut-off under specified conditions in an operationally safe… Read more
Dec 20, 2012 | By Edvard Csanyi
Energy and Power
The Solid State Relay (Static Relay) Overview
The static relay is the next generation relay after electromechanical type.The Solid Static relays was first introduced in 1960’s. The term ‘static’ implies that the relay has no moving mechanical parts in it. Compared to the Electromechanical Relay, the Solid… Read more
Dec 19, 2012 | By Jignesh Parmar
Energy and Power
The Good Old Electromechanical Protective Relay
This is the first generation oldest relaying system and they have been in use for many years. They have earned a well-deserved reputation for accuracy, dependability, and reliability. There are two basic types of operating mechanisms: Electromagnetic-attraction relay and Electromagnetic-induction… Read more
Dec 18, 2012 | By Jignesh Parmar
Energy and Power
Using Protective Relay For Fighting Against Faults
Introduction to Protective Relay Working Principle of Protective Scheme What is Relay? Functions of Protective Relay Desirable qualities of protective relaying Terminology of protective relay History of Protective Relay Types of Relays Types of Relay based on Relay Operation Mechanism… Read more
Dec 17, 2012 | By Jignesh Parmar
Protection
Power Line Carrier Communication (PLCC)
Use of PLCC in modern electrical power system is mainly for telemetry and telecontrol. Tele means remote. Telemetry refers to science of measurement from remote location. Introduction Major goal/Application of PLCC Main Components of PLCC: Coupling Capacitor Line trap Unit… Read more
Dec 14, 2012 | By Asif Eqbal
Energy and Power
Rogowski Coil Construction
Figure 1 shows the construction of a Rogowski coil, an air-core current transformer that is especially well suited to measuring ripple currents in the presence of a DC component or measuring pulsed currents. The raw output is proportional to the… Read more
Dec 13, 2012 | By Edvard Csanyi
Energy and Power
21 Safety Rules for Working with Electrical Equipment
A safe work environment is not always enough to control all potential electrical hazards. You must be very cautious and work safely. Safety rules help you control your and others risk of injury or death from workplace hazards. The good… Read more
Dec 12, 2012 | By Edvard Csanyi
Energy and Power
The Role of Fuse in Low Voltage Systems
A fuse is the very important protective device used to automatically disconnect a live circuit when a predetermined value of current & or time of predetermined current is exceeded. To simplify, fuse is actually the wire designed to melt, and thereby… Read more
Dec 11, 2012 | By Edvard Csanyi
Energy and Power
What Is The Basic Insulation Level (BIL)
Insulation levels are designed to withstand surge voltages, rather than only normal operating voltages. Since the transmission & distribution lines and substation equipment are protected by surge arresters draining the surges rapidly before the insulation is damaged, the arrester must… Read more
Dec 03, 2012 | By Edvard Csanyi
Protection
The Purpose Of Transformer Gas Relay
The transformer gas relay is a protective device installed on the top of oil-filled transformers. It performs two functions. It detects the slow accumulation of gases, providing an alarm after a given amount of gas has been collected. Also, it… Read more
Nov 29, 2012 | By Edvard Csanyi
Protection
Surge Protection for Frequency Converters
In principle a frequency converter consists of a rectifier, a d.c. link converter, an inverter and of the control electronics (Figure 1 above). At the input of the inverter the single phase or interlinked, three-phase a.c. voltage is changed into a… Read more
Nov 26, 2012 | By Edvard Csanyi
Energy and Power
Purpose of Miniature Circuit Breakers (MCBs)
Miniature circuit breakers (MCB) are primarily designed to protect cables and lines against overload (thermal) and short-circuit (electromagnetic). They thus care for protecting this electrical equipment against excessive temperature rises and destruction in the event of a short-circuit. They meet the requirements… Read more
Nov 24, 2012 | By Edvard Csanyi
High Voltage
HV Instrument Current Transformers in T&D
Electrical measurements on a high-voltage transmission and distribution systems cannot be made practically or safely with direct contact to the power carrying conductors. Instead, the voltages and currents must be brought down to a safe and usable level that can… Read more
Nov 23, 2012 | By Edvard Csanyi
Electric Motor
Stator Overheating Protection
All motors need protection against overheating resulting from overload, stalled rotor, or unbalanced stator currents. For complete protection, three-phase motors should have an overload element in each phase. This is because an open circuit in the supply to the power… Read more
Nov 19, 2012 | By Edvard Csanyi
Protection
Principles and Characteristics of Distance Protection
Distance relays are one of the most important protection elements in a transmission line. These relays may sometimes be set based in percentages of the line impedances, for example a typical setting for zone 1 is 80% of the impedance… Read more
Nov 13, 2012 | By Edvard Csanyi
