Types of Conductor

-

Conductor:

Conductor is a metal that permit allow to flow of electron from particle to particle inside it.An electrical conductor allows the electric charges to easily flow through them. The property of conductors to “conduct” electricity is called conductivity. Such materials offer less opposition or “resistance” to the flow of charges. Conducting materials allow easy charge transfer because of the free movement of electrons through them.

Properties of Electrical Conductor:

The main properties of electrical conductors are as follows:

- A conductor always allows the free movement of electrons or ions.

- The electric field inside a conductor must be zero to permit the electrons or ions to move through the conductor.

- Charge density inside a conductor is zero i.e. the positive and negative charges cancel inside a conductor.

- As no charge inside the conductor, only free charges can exist only on the surface of a conductor.

- The electric field is perpendicular to the surface of that conductor.

The types of conductors are following:

1.) Solid conductor:

Solid Conductor are made up of one single wire. It has high skin effect.Mostly, solid conductor are used for heavy duty application.

2.) Stranded Conductor:

Eddy current losses are very much lesser than the solid conductor. Proximity and skin effect is reduced using stranded conductors.

Fig. Solid Conductor & Stranded conductor

3.) Hollow conductor:
It's preferred under heavy current, i.e. more than 1000 Amp. Hollow Conductor are used in transmission lines to reduces corona loss. And, it also reduces reactance of electric transmission lines.

4.) Composite Conductor:

It's used for voltage less and equal to 220 kV. Composite conductors reduce proximity effect and also reduces skin effect up to certain extent.

5.) Bundle Conductor:

Bundle conductor are used for greater than and equal to 275Kv. Bundled conductors are employed in Extra High Voltage (EHV) transmission as at higher voltages corona effect is significant. The advantages of bundle Conductor are :- Voltage gradient reduced so corona loss reduced and Power system stability increases.

Fig. Bundled conductor







Comments

Post a Comment

Popular posts from this blog

Reactive Power

-
Reactive Power Reactive power is used to control voltage over transmission line or in power systems network. Mathematically, Reactive Power is product of volage and current with sin(phi).        Q = VI sin(phi) -----------(1) Here, we observed that from eq.(1), Reactive Power depends upon flux (phi). And We have,   V = E1 = 4.44 Nf(phi) ----------(2)     Where, phi = magnetic flux(Weber)                     N  = No. of turns                     f   = freuency(Hz) From eqn(2), We can says that, voltage depend upon flux. By this way we can say that, Reactive Power depends upon voltage. In case of synchronous machine: Over excitation ---> Over flux ---> Over R.P Need of Reactive Power : Voltage control in power system is important for proper operation for electrical devices/elements to prevent from damage such as :  -To reduces Transmission lines losses -To mantain the ability of system and prevent Voltage collapse. -Over heating of Electrical machine - Reactive Power (VARs) is used
Read more

Surge impedance Loading

-
Surge Impedance Loading: A transmission line may considered as generating capacitive reactive volt-amperes in shunt capacitance and consuming (absorbing) inductive reactive volt-amperes in its series inductance. The load at which inductive and capacitive reactive volt amperes are equal and opposite is called the surge impedance Loading or (nature load of the line). "The power delivered by the line to purely resistive load equal to its surge impedance the load at which the inductive and capacitive reactive volt-amperes are equal and opposite, is called surge impedance Loading of the line." Capacitive volt-amp. generated in the line = V *I = V / Xc = V² / ωL Inductive volt-amp.  absorbed in the line = V * I = I *XL = I² *ωL Under natural load conditions, Capacitive volt-amp. = Inductive volt-amp.             V² * wc   =    I² * ωL    or,  V / I   = √(L/C) =  Zo = Surge impedance At this load V and I are in same phase. At this Zo is purely resistive. There is not present imagina
Read more

Ferranti Effect

-
Image
 When Recieving end of the transmission line is operating under no load condition or lightly condition,sending end voltage(Vs) is less than Recieving end Voltage (VR). Ferranti Effect is due to charging current Ic of the line. In medium Transmission lines; At No-Load,   Hence, Recieving end Voltage is more than sending end voltage. This is Ferranti Effect. This is also show that Ferranti Effect depends on the frequency and Electrical Length of the line. Now Let's see; At Load condition, Here, we saw that, No Ferranti Effect occurs at Load condition. **Ferranti Effect is more dominanting in communication Lines.** ## Elimination of Ferranti Effect: --To eliminate/nullify Ferranti Effect, we need inductor parallel to the capacitor.
Read more