Open-circuited line

In a similar manner to a short-circuited line, the solutions of the voltage and the current are obtained in the following form  

The input impedance of the finite line seen from the sending end is expressed as 

Input impedance of an open-circuited line. r = 1.3 mm, y = 60 cm between conductors, and /=800 Hz. 

The line is in a resonant condition when the denominator of the earlier 

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Where, St is the MVA rating of the transformer, and Vqs is the open-circuit line voltage of the secondary winding. 

FIGURE 1.16 Z(/) - 0 characteristic of a lossless open-circuited line. 

Open-circuited line An open-circuited line Zq with an incoming wave e(x - ct) from the left in Figure 1.37a is equivalent to an infinite line with the incoming wave from the left and another incoming wave e(x + ct) from the right with the same amplitude and the same polarity as in Figure 1.37b. 

FIGURE 1.37 (a) An open-circuited line, (b) An equivalent circuit. 

FIGURE 1.44 Voltage and current responses on an open-circuited line, (a) An open-circuited line, (b) V2(0- (c)... 

It is well-known that a distributed parameter line is approximated by a lumped parameter circuit such as a PI equivalent and an L equivalent. For example, the open-circuited line in Figure 2.2 is approximated by Figure 2.55 with the I equivalent. Let us analyze the switching surges in this circuit. 

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