Testing and Commissioning Requirements for Switchgear

Before starting the switchgear testing an approved testing & commissioning engineer should be appointed in order to thoroughly review all the applicable drawings and specification, and to become totally familiar with all systems and the design intent. Experience certificate of T&C engineer to be submitted for client approval and test and commissioning should be done under… Read More »

Air Blast Circuit Breaker | Construction & Operating Mechanism

A circuit breaker is a mechanical switching device, capable of making, carrying and breaking currents under normal circuit conditions. It is also capable of making and carrying currents for a specified time and breaking currents under specified abnormal circuit conditions, such as those of a short circuit. Air Blast Circuit Breaker is one of major component… Read More »

What is On Load Tap Changer OLTC in Transformers

A tap changer is a device fitted to power transformers for regulation of the output voltage to required levels. On-load tap-changers (OLTCs) are indispensable in regulating power transformers used in electrical energy networks and industrial applications. OLTC changer alters the turn ratios of the transformer on the system by altering the number of turns in… Read More »

Dry Type Substation Transformers Technical Features

Most transformer companies offer standard engineered products only, and ask the users to make it fit their applications. Also these companies can engineer the product both electrically and mechanically to fit virtually any application. Typically companies employ three winding styles for Special Design Dry Type transformers, based on kVA, voltage and BIL requirements. The ability to… Read More »

Medium Voltage Indoor Dry Type Transformers Rating, Rated Voltage, Frequency and Ratio

The rated voltage ratio of the transformers at no load normally is specified at 50 Hz, this being related to the principal tapping of the transformer. Tapping shall be provided on the primary winding to provide a ratio variation of +7.5% and –2.5% in steps of 2.5%. The tap charge mechanism is of the off load… Read More »

How To Measure Transformer Winding Resistance

Transformer winding resistance is very important factor for the life of any transformer, this test is part of type tests, routine tests and field tests. The purpose of winding resistance test is to determine the following: Calculation of the I2R losses in transformer. Calculation of winding temperature at the end of temperature rise test of transformer. As a benchmark… Read More »