Energy and Power
Earthing (grounding) transformer – Voltages during a ground fault
Earthing Transformer or grounding transformer is the neutral grounding transformer – star connected on the primary and has an open delta on secondary. Open Delta has two terminals. A resistor is connected across these two terminals. Whenever a fault occurs, voltage… Read more
May 05, 2014 | By Asif Eqbal
Testing and Commissioning
Inspection and Test procedures for Instrument Transformers
Visual and Mechanical Inspection Electrical Tests: Electrical Tests – Current Transformers Electrical Tests – Voltage Transformers Electrical Tests – Coupling-Capacitor Voltage Transformers Electrical Tests – High-Accuracy Instrument Transformers (Reserved) Test Values: Test Values: Visual and Mechanical Test Values: Current Transformers… Read more
Apr 04, 2014 | By Edvard Csanyi
Testing and Commissioning
Testing of power transformer – Measurement of impedance voltage and load loss
The measurement is carried out to determine the load-losses of the transformer and the impedanse voltage at rated frequency and rated current. On Figure 1 above (Circuit for the impedance and load-loss measurement) there are following figures: G1 – Supply… Read more
Mar 12, 2014 | By Edvard Csanyi
Testing and Commissioning
Testing Procedures for HV Voltage Transformers
Equipment required for testing General inspection Insulation Resistance Test Polarity Test Transformer Turns ratio test Following equipment is necessary to perform testings: Polarity test kit Megger 500-5000V Ohmmeter Multimeter Autotransformers & Step-up transformers Go up to the Content General visual… Read more
Feb 28, 2014 | By Edvard Csanyi
Transformers
How challenging can be transporting of a Large Power Transformer (LPT)
Transporting an Large power transformer (LPT) can be quite challenging. LPTs large dimensions and heavy weight pose unique requirements to ensure safe and efficient transportation. Current road, rail, and port conditions are such that transportation is taking more time and… Read more
Feb 14, 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
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
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
Transformers
Large power transformer tailored to customers’ specifications
An LPT (Large Power Transformer) is a large, custom-built piece of equipment that is a critical component of the bulk transmission grid. Because LPTs are very expensive and tailored to customers’ specifications, they are usually neither interchangeable with each other… Read more
Dec 30, 2013 | By Edvard Csanyi
Testing and Commissioning
Eight important checks to do before powering up the dry-type transformer
The transformer should be powered up only after checking the following items: name plate ratings, parallel operation, connections: cables, busbars, tap change connections, grounding connection, thermal protective device, impurities removal and insulation resistance test. Make sure the name plate ratings… Read more
Oct 23, 2013 | By Edvard Csanyi
Power Substation
Dry-Type Transformer Installation and Ventilation Requirements
Dry-type transformers should be installed over foundations that are properly leveled and capable to withstand their weight. When a transformer is fitted with wheels, make sure the equipment will be equally supported on its base points in order to assure… Read more
Oct 21, 2013 | By Edvard Csanyi
High Voltage
Five special transformers for industrial applications you should know about
A number of industry applications require specific industrial transformers due to the usage of power (current) as a major resource for production. Electric arc furnaces (EAF), ladle furnaces (LF) and high-current rectifiers need a specific design to supply the necessary… Read more
Sep 23, 2013 | By Edvard Csanyi
Testing and Commissioning
Identifying The Primary And Secondary Phasor Polarities Of Transformer – Polarity Test
This is needed for identifying the primary and secondary phasor polarities. It is a must for poly phase connections. Both a.c. and d.c methods can be used for detecting the polarities of the induced emfs. The transformer is connected to… Read more
Aug 26, 2013 | By Edvard Csanyi
Power Substation
Total Losses in Power Distribution and Transmission Lines
This technical article discusses two types of transmission and distribution losses, technical losses and non-technical losses (or commercial losses). Power generated in power stations pass through large and complex networks like transformers, overhead lines, cables and other equipment and reaches… Read more
Aug 19, 2013 | By Jignesh Parmar
IEC Standards
An Overview of IEC 60076-10 – Determination Of Sound Levels Of Power Transformers
The audible sound radiated by transformers is generated by a combination of magnetostrictive deformation of the core and electromagnetic forces in the windings, tank walls and magnetic shields. Historically, the sound generated by the magnetic field inducing longitudinal vibrations in the… Read more
Aug 14, 2013 | By Edvard Csanyi
