Electrical Lectures
What is the short-circuit switching (making / breaking) capacity?
The switching capacity is the r.m.s value of a current at a given power factor cos φ as well as a given rated voltage at which a switchgear or a fuse can still shut-off under specified conditions in an operationally… Read more
Feb 10, 2014 | By Edvard Csanyi
Energy and Power
Electrical Preventive Maintenance of Air Circuit Breakers
Remove and clean interphase barriers. Clean all insulating materials with vacuum and/or clean lint free rags. If it is necessary to use cleaning solvents, use only solvents recommended by the manufacturer. Inspect for (early) signs of corona, tracking, arcing, or… Read more
Feb 07, 2014 | By Edvard Csanyi
Energy and Power
Purposes and Examples of Safety Interlocking Devices
Most switchboards and motor control centres are fitted with a variety of electrical and mechanical safety interlocking devices. Their purposes are to protect against for example: Withdrawing the switching device while it is carrying load or fault current. Prevent the switching… Read more
Feb 05, 2014 | By Edvard Csanyi
Energy and Power
Conceptual Model of Smart Grid Framework by IEC
From a communication point of view, each system plays the role of either supplier or consumer of information, or more typically both. In addition to this intersystem communication, these systems consist of subsystems with specific internal communications. The following paragraphs… Read more
Feb 03, 2014 | By Edvard Csanyi
Energy and Power
MV Circuit Breaker Or Vacuum Contactor? (2)
Continued from first part: MV Circuit Breaker Or Vacuum Contactor? (Part 1) When applied properly, both medium-voltage circuit breakers and medium-voltage fused contactors should provide decades of reliable service. Applied incorrectly, either can lead to major headaches. Characteristic Circuit Breaker Contactor… Read more
Jan 31, 2014 | By Mohan Krishnasamy
Energy and Power
MV Circuit Breaker Or Vacuum Contactor? (1)
To compare the application of medium-voltage circuit breakers and of fused contactors, we must understand the basic characteristics of each switching technology. Comparison presented here shows the major characteristics of medium-voltage circuit breakers and medium-voltage fused contactors that influence the… Read more
Jan 29, 2014 | By Mohan Krishnasamy
Power Substation
6 Simple Rules to Ensure Substation Safety
Another extremely important substation engineering aspect is associated with safety protection. It is fair to say that safety is always a No. 1 priority in substation design, operation and maintenance. Unlike the case where a higher reliability required a larger… Read more
Jan 27, 2014 | By Edvard Csanyi
Energy and Power
Dimensioning of Power Distribution Systems (2)
Continued from the first part: Dimensioning of Power Distribution Systems (1) Dimensioning of cable routes and devices follows the maximum load currents to be expected at this distribution level. As a rule: Ib max = ∑ installed capacity x simultaneity… Read more
Jan 24, 2014 | By Edvard Csanyi
Testing and Commissioning
Power Transformer Capacitance and Dissipation Factor Test
The capacitance and dissipation factor test is an AC low voltage maintenance test and is very similar to the power factor test. While the transformer preparation is identical to the power factor test procedure, there is no requiremnts to make… Read more
Jan 22, 2014 | By Edvard Csanyi
Energy and Power
Dimensioning of Power Distribution Systems (1)
When the basic supply concept for the electricity supply system has been established, it is necessary to dimension the electrical power system. Dimensioning means the sizing rating of all equipment and components to be used in the power system. In… Read more
Jan 20, 2014 | By Edvard Csanyi
Testing and Commissioning
How to perform a power transformer turns ratio test
Power transformer turns ratio test is an AC low voltage test which determines the ratio of the high voltage winding to all other windings at no-load. The turns ratio test is performed on all taps of every winding. The Transformer… Read more
Jan 17, 2014 | By Edvard Csanyi
Energy Efficiency
Automatic transfer switch (ATS) between two low-voltage utility supplies
Multiple utility services may be used as an emergency or standby source of power. Required is an additional utility service from a separate source and the required switching equipment. Figure 1 shows automatic transfer between two low-voltage utility supplies. Utility… Read more
Jan 15, 2014 | By Edvard Csanyi
Electric Motor
Calculating the short-circuit current across the terminals of a synchronous generator
Calculating the short-circuit current across the terminals of a synchronous generator is very complicated because the internal impedance of the latter varies according to time. When the power gradually increases, the current reduces passing through three characteristic periods: Subtransient (enabling determination… Read more
Jan 13, 2014 | By Edvard Csanyi
High Voltage
8 main disadvantages of HVDC transmission
Few weeks back I posted an article about advantages of HVDC over HVAC transmission systems. Advantages of HVDC are numerous and very well recognized, but like everything on this earth this system has other side too. The eight main disadvantages… Read more
Jan 10, 2014 | By Edvard Csanyi
Energy and Power
U.S. Renewable Energy – The Facts!
About 82% of the nation’s energy comes from fossil fuels, 8% from nuclear, and 9% from renewable sources. Wind is the fastest growing renewable source, but contributes only 1% of total energy used in the U.S. The examples below illustrate… Read more
Jan 08, 2014 | By Edvard Csanyi
