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
Low Voltage
Example of MV/LV network structure with dual fed main MV switchboard
Connected to article: Example of standard MV/LV network structure MV consumer substation; The main MV switchboard can be backed up by a generator set and it feeds two MV/LV transformers; MV switchboard can be GIS or AIS and consist of… Read more
Jan 06, 2014 | By Edvard Csanyi
Energy and Power
Driving Distributed Energy with Smart Networks
The smart network will set up a virtuous cycle for distributed generators and energy storage devices. It will grow the market by opening up more niches where distributed energy is economically competitive. This growth will lead to economies of scale… Read more
Jan 03, 2014 | By Edvard Csanyi
Transformers
Economic Evaluation of Transformer Losses
Transformer losses represent power that cannot be delivered to customers and therefore have an associated economic cost to the transformer user/owner. A reduction in transformer losses generally results in an increase in the transformer’s cost. Depending on the application, there may be… Read more
Jan 01, 2014 | By Edvard Csanyi
