In this system of earthing, the neutral point is earthed through the primary winding of a single-phase voltage transformer as shown in the figure below. The secondary winding of the voltage transformer is connected in series with…
Generally, at every voltage level, the neutral point is available from the generator or transformer i.e., when the star connected. But when there is a delta connection or when the neutral is desired on the busbars etc., then the …
The resistance offered to the lightning current when the tower is directly exposed to lightning is called tower footing resistance. It is the value of footing resistance measured at 50 Hz. The performance of the line purely depen…
When the neutral of the system is directly connected to the ground with negligible resistance and reactance between them, then the grounding system is known as solid grounding or effective grounding. A system is said to be solid…
The system in which the neutral point is grounded through a current limiting device (resistor) is known as a resistance grounded system and the grounding is referred to as resistance grounding. This method is used when it becomes…
The system in which the neutral point is grounded through impedance which is highly reactive is known as a reactance grounded system and the grounding is referred to as reactance grounding. Necessity of Reactance Grounding : If…
The neutral grounding is nothing but connecting the neutral point of the supply system or rotating machine or transformer to the earth directly or through some circuit elements. A three-phase system can be operated in two ways, t…
Phenomenon of Arcing Ground : Due to lightning surges, puncture of an insulator on an overhead line, falling of a branch, etc., an arc between the phase conductor and earth develops. The arc extinguishes and restrikes in a repea…
The Peterson coil is an adjustable iron-cored reactor connected between the neutral point and ground. It has the capability of producing resonance by turning the capacitance of the healthy phases during a line to ground fault. It…
Resonant grounding is also known as arc suppression coil grounding as it uses an arc suppression coil in the neutral earthing circuit i.e., the neutral of the system is connected to the ground through an adjustable iron cored rea…
The ungrounded neutral system is a neutral system in which there is isolation between neutral and ground i.e., there is no electrical connection between neutral and ground. Hence the ungrounded neutral system is also called an is…
A valve type lightning arrester is an improved and expensive lightning arrester which is also called a nonlinear surge diverter. A valve type arrester gets its name from the fact that a nonlinear resistor regulates itself from th…
What is Surge Absorber or Lightning Absorber? A surge absorber is a protective device that absorbs the high voltage surges and reduces the steepness of the surge wavefronts. The traveling waves set up by the surges on the transm…
Power transmission lines and associated equipment in the substations are subjected to overvoltage which is generally due to lightning discharge or internal causes (switching operation, sudden changes in load, insulation failure, …
