HVDC Back to Back System

As we know that High voltage AC is used to transmit the electrical power for reducing the power transmission losses and because of the flexibility of AC System. In a transmission system different Grids are interconnected but some time it may happen that one or more Grid or Power System may not be in synchronization … Read more

Why for Transmission Lines R/X ratio is low but for Distribution Lines R/X ratio is high?

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

Difference between Isolators and Sectionalizers in Power System

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

Transformer Inrush Current

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

Q Factor / Quality Factor of a Coil

The ratio of the inductance L to the resistance R of a coil remains constant for different winding arrangements in the same volume and shape. It makes sense to define this value as a figure of merit to distinguish different coil structures. The quality factor Q is defined by this ratio of L and R. … Read more

Speed Control of DC Motor by Varying Field Flux

In previous post “Speed Control of DC Motor” we discussed the method of speed control of DC Motor by Armature Circuit Resistance Control Method. In this post we will discuss the method of speed control of DC Motor by varying the Field Flux which is known as Field Weakening Method. By Field Weakening Method of … Read more

Two Wattmeter Method – Measurement of Three Phase Power

There are three methods which are used for the measurement of three phase power in three phase circuits. The three methods are: Three Wattmeter Method Two Wattmeter Method Single Wattmeter Method In this post, we will discuss the Two Wattmeter Method for power measurement. Two Wattmeter Method: In two wattmeter method, a three phase balanced … Read more

Speed Control of DC Motor

DC Motor speed control means to have full control on the speed of DC Motor. The variation in speed of DC Motor because of variation in load is not the speed control. Therefore intentional variation in speed of DC Motor is called Speed Control. As we know that for a DC Motor having armature resistance … Read more

Brushless Excitation System

Brushless Excitation System is a technology for providing the field current to the Synchronous Generator without using Slip Ring and Carbon Brushes. As this method of Excitation i.e. Brushless Excitation System do not use Carbon Brushes, therefore the losses because of contact resistance of carbon brushes is eliminated. Also, in case of initial start up … Read more