Energy and Power
220V DC system at thermal power station
The 220V DC system supplies direct current as source of operating power for control, signaling, relays, tripping and closing of switchgears, emergency motors of most important auxiliary systems. Under normal conditions of station generation, the storage battery units are kept… Read more
Feb 15, 2012 | By Bipul Raman
Renewable Energy
Solar energy is free, but what does it really cost?
“Solar energy is free, but it’s not cheap” best sums up the major hurdle for the solar industry. There are no technical obstacles per se to developing solar energy systems, even at the utility megaWatt level (e.g., 14 MW utility… Read more
Feb 13, 2012 | By Edvard Csanyi
High Voltage
Protection Of Generators And Transformers
As Generators and transformers are major components of a power system, so it is quite necessary to take all the preventive measures for the protection of transformers and generators. These are the following ways (ANSI codes) we use to protect… Read more
Feb 11, 2012 | By Bipul Raman
Electrical Lectures
Types of neutral earthing in power distribution (part 2)
Resistance grounding has been used in three-phase industrial applications for many years and it resolves many of the problems associated with solidly grounded and ungrounded systems. Resistance Grounding Systems limits the phase-to-ground fault currents. Continued from Types of neutral earthing… Read more
Feb 09, 2012 | By Jignesh Parmar
Cables
Discussing About LV And HV Electrical Cables
Space is really a critical criterion when discussing electrical cables and wires. In a low-voltage (LV) plastic-sheathed cable with conductor cross-sections of up to 10 mm2 per conductor or in high-voltage (HV) cables (Figure 2), the lion’s share of the… Read more
Feb 08, 2012 | By Edvard Csanyi
Electrical Lectures
Types of neutral earthing in power distribution (part 1)
In the early power systems were mainly Neutral ungrounded due to the fact that the first ground fault did not require the tripping of the system. An unscheduled shutdown on the first ground fault was particularly undesirable for continuous process… Read more
Feb 06, 2012 | By Jignesh Parmar
Maintenance
Purpose and maintenance of transformer bushings
The two most common types of bushings used on transformers as main lead entrances are solid porcelain bushings on smaller transformers and oil-filled condenser bushings on larger transformers. Solid porcelain bushings consist of high-grade porcelain cylinders that conductors pass through…. Read more
Feb 05, 2012 | By Edvard Csanyi
Electric Motor
Internal losses that reduce efficiency of a DC generator
There are four internal losses that contribute to lower efficiency of a DC generator. Copper losses Eddy-current losses Hysteresis losses Mechanical losses Copper loss is the power lost as heat in the windings; it is caused by the flow of… Read more
Feb 03, 2012 | By Edvard Csanyi
Electric Motor
Three phase induction motors – Operating principle
An electric motor converts electrical energy into a mechanical energy which is then supplied to different types of loads. A.c. motors operate on an a.c. supply, and they are classified into synchronous, single phase and 3 phase induction, and special… Read more
Feb 03, 2012 | By Henry James
Electrical Lectures
About Permeability And Permitivity
The strength of electric field or electrostatic force strength or intensity of field (all synonymous terms) is measured & expressed in terms of force experienced by unit positive charge placed in sphere of influence of another source charge, which has… Read more
Feb 01, 2012 | By Asif Eqbal
Energy and Power
Using VLT AQUA Drive in submersible pump application
The system consists of a submersible pump controlled by a Danfoss VLT AQUA Drive and a pressure transmitter. The transmitter gives a 4-20 mA feedback signal to the VLT AQUA Drive, which keeps a constant pressure by controlling the speed… Read more
Jan 30, 2012 | By MarkoCvrkota
High Voltage
Ceramic (Porcelain and Glass) Insulators
Porcelain is the most frequently used material for insulators. Insulators are made of wet, processed porcelain. The fundamental materials used are a mixture of feldspar (35%), china clay (28%), flint (25%), ball clay (10%), and talc (2%). The alternative method… Read more
Jan 27, 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
Cables
EHV/HV Underground Cable Sheath Earthing (part 2/2)
Continued from previous part: EHV/HV Cable Sheath Earthing (part 1/2) Link Box is electrically and mechanically one of the integral accessories of HV underground above ground cable bonding system, associated with HV XLPE power cable systems. Link boxes are used… Read more
Jan 21, 2012 | By Edvard Csanyi
