what is Transposition of lines? Transmission line transmits bulk power at relatively higher voltages.These lines gives rises to electromagnetic and electrostatic fields of sufficient magnitudes which induces currents and voltages in the neighboring telephone lines.The currents so induced are superimposed on the true speech currents in the neighboring telephone wires and set up distortion,while the … Read more
Medium transmission line Transmission line having length between 80 Km and 200 Km and line voltage between 20 KV and 100 KV fall under medium transmission lines. In medium transmission line with the increase in the length and the operating voltage shunt capacitance becomes more pronounced and the capacitive current is appreciable.Hence line capacitance is … Read more
Short transmission line Transmission line having the length lesser than 80KM and operating voltage lower than 20 KV falls under short transmission line.The capacitance effects are neglected in short transmission line due to smaller distance and lower line voltage .In a short transmission line the shunt conductance and shunt capacitance are neglected and only the … Read more
Surge Impedance surge Impedance or characteristics impedance is the ratio of the amplitudes of voltage and current of a single wave propagating along the line i.e a wave travelling in one direction in the absence of reflections in other direction.surge impedance is the characteristics impedance of a loss-free line.The square root of the ratio of … Read more
Potential Transformers(PTs) Potential transformer or voltage transformer are used in electrical power system for stepping down the system voltage to a safe value which can be fed to low ratings meters and relays. Commercially available relays and meters used for protection and metering, are designed for low voltage. This type of transformer is generally employed … Read more
Current Transformer The Current Transformer ( C.T. ) is a type of “instrument transformer” that is designed to produce an alternating current in its secondary winding which is proportional to the current being measured in its primary.current transformer are connected in ac power circuits to feed the current coils of indicating and metering instruments (ammeters, … Read more
Definition: For all the electrical systems electric current flows from the region of higher potential to lower potential region to compensate for the electrical potential difference that exist in the system.In all practical cases the sending end voltage is higher than the receiving end voltage so the electric current flows from the source to the … Read more
The generated electrical energy is distributed form the urban areas and delivered to the ultimate consumers through a network of transmission and distribution.There may be the variation of voltage at the consumers terminal which may cause erratic operation or even malfunctioning of the consumers appliances such as motors,lamps and other load.The main cause of the … Read more
Dc motor are indispensable for many adjustable speed drives as Speed control can be achieved in dc motor.The expression for for speed of a dc motor is given by: The above expression reveals that the speed can be controlled by adjusting any one of the three factors appearing on the right hand side of the … Read more
Introduction Bus-bar is one of the vital elements in electric power stations and substations. The term bus is derived from the word omnibus which means collector of things. Thus the electrical bus bar is the collector of electrical energy at one location. Bus bar are convenient means of connecting switches and other equipment’s into various … Read more