In the given circuit if R = 0 then the circuit becomes purely inductive. So the phase angle between v(t) and i(t) is 90°.
Isolator or disconnecting Switch: An isolator is a switch that is designed to open a circuit under no-load condition. Its main purpose is to isolate one portion of the circuit from the other and is not allowed to be opened while current is flowing in the line. Such switches are used on both sides of a circuit breaker so that its repair works or replacement could be done.
Note that an isolator is never opened until the circuit breaker in the circuit is opened and it is closed before the circuit breaker is closed. If an isolator is switched OFF when a high current is flowing through the circuit, a heavy spark will be produced. This heavy spark may break the supporting insulator of the isolator which may cause a fatal accident to the operator.
The total number of the conductor in stranded cable is given by
N = 3x2 − 3x + 1
x = no. of layer
For layer 1
N1 = 3(1)2 − 3(1) + 1
N1 = 1
For layer 2
N2 = 3(2)2 − 3(2) + 1
N2 = 7
In layer 2 no. of conductor = N2 − N1 = 7 − 1 = 6
For layer 3
N3 = 3(3)2 − 3(3) + 1
N3 = 19
In layer 3 no. of conductor = N3 − N2 = 19 − 7 = 12
Mutual inductance between the two coils is K = √L1.L2
K = √2 × 8
k = √16
k = 4 H
Voltage regulation:- When a transmission line is carrying current, there is a voltage drop in the line due to resistance and inductance of the line. The result is that the receiving end voltage (VR) of the line is generally less than the sending end voltage (Vs). This voltage drop (Vs − VR) in the line is expressed as a percentage of receiving end voltage VR and is called voltage regulation.
The difference in voltage at the receiving end of a transmission line between conditions of no-load and full-load is called voltage regulation and is expressed as a percentage of the receiving end voltage. Mathematically,
% Voltage regulation = (Vs − VR) ⁄ VR × 100
Obviously, it is desirable that the voltage regulation of a transmission line should be low i.e., the increase in load current should make very little difference in the receiving end voltage. In the transmission line, the voltage regulation is negative whenever the receiving end voltage VR is Greater than the sending end voltage.
The regulation will depend upon the power factor of the load. If the power factor is lagging, the voltage at the sending end is more than that at the receiving end. Hence, voltage regulation is positive. On the other hand, if the power factor is leading, the voltage at the sending end will be somewhat less than that at the receiving end. In that case, the regulation is negative.