Tricky but Easy Electrical Engineering!
BDV test means Breakdown Voltage Test. It is done for checking the dielectric strength of the oil of the Transformer. Dielectric strength means the maximum capacity to withstand voltage of insulating oil. This test shows the dielectric strength of Transformer oil. In transformer oil has mainly two purposes, first for insulation, second as cooling of … Read more
Conservator is a cylindrical tank mounted on supporting structure on the roof of the transformer’s main tank. Function: When transformer is loaded and when ambient temperature rises, the volume of oil inside transformer increases. A conservator tank of transformer provides adequate space to this expanded transformer oil. It also acts as a reservoir for transformer … Read more
A Phase Imbalance Fault indication on a motor monitor means that the voltage and / or current in one phase winding of the motor is not the same as the other two phases by an amount that exceeds a settable maximum.This means something is wrong and need to be corrected. The most common reason for … Read more
In any electrical system, we do the neutral grounding at the power source e.g. the star-points of generators or transformers. By keeping the grounded neutrals at the power source, earth fault current will have a return path from the point of short-circuit at downstream to the source. In this way the direction of earth fault … Read more
In AC circuit breakers/ arc extinction is achieved at the natural current zero of the AC waveform used. But in DC circuit breakers / natural zero of voltage and current is not available as both are continuously available. Thus for extinction of an arc, artificial current zero is required to be introduced. Such an artificial … Read more
SFRA stands for Sweep Frequency Response Analysis. This test is very reliable for condition monitoring of physical condition of transformer winding, core and above all core & winding integrity. Why to conduct SFRA test? The winding of Transformer may be subjected to mechanical stresses during transportation, heavy short circuit faults, transient switching impulses & lightening impulses etc. … Read more
Relays are electro-mechanical switches that have coil and two types of contacts that is NO & NC. But a Programmable Logic Controller, PLC is a mini computer which can take decision based on the programme and its input & output. Thus a PLC can perform many functions with the same hard wiring. A simple architecture … Read more
Even though high R/X ratio causes more Voltage drop in Distribution System, Distribution lines are designed such that R/X comes more. Whereas for Transmission Line, low R/X ratio reduces ohmic loss, so for Transmission line it is beneficial. Then why Distribution Lines are designed for high R/X?? I am here explaining the reason. Actually, lines … Read more
An isolator is a switch used in power lines, to completely open (physically) a specific section of line, when maintenance or modification work is to be done. The isolator can be operated manually, or in some cases, opened by energizing a motor. With a three-phase system, the isolator opens all three lines. A picture of Isolator is shown below … Read more
In this post we will discuss the Magnetizing Inrush Current in a Power Transformer. Magnetizing Inrush urrent in Transformers results from any abrupt changes of the magnetizing voltage. This current in transformer may be caused by energizing an unloaded transformer, occurrence of an external fault, voltage recovery after clearing an external fault and out-of phase … Read more