Q3(a) In an overhead line, there are THREE units in the string of insulators having phase voltage of 19.06kV. If the shunt capacitance between each insulator pin and earth is 0.22 times than insulator capacitance (1) Calculate the distribution of voltage over 3 insulators. (i) Explain why string efficiency, will not reach to 100% under practical condition.

In an outdoor substation the three bus-bar conductors are supported by units of post type insulators. Each unit consists of a stack of 3 pin type insulators fixed one on the top of the other. The voltage across the lowest insulator is 15kV and that across the next unit is 12kV. Estimate: i. ratio of mutual to self-capacitance ii. the bus-bar voltage of the substation. iii. Efficiency across the string of insulators

In an overhead line, there are three units in the string of insulators having line voltage of 33kV. If the shunt capacitance between each insulator pin and earth is 0.11 times than self-capacitance of each insulator, (i) Calculate the distribution of voltage over 3 insulators. (ii) Explain to how to make uniform voltages

7. Each of three insulators forming a string has self-capacitance of "C farad. The shunt capacitance of each cap of msulator is 0 25 C to earth and 0-15 C to line. Calculate the voltage distribution across each insulator as a pecentage of line voltage to earth and the string efficiency.

Which of the following statements is/are true? (A In purely inductive circuit, the current leads voltage. (B) In purely resistive circuit, the current lags voltage. C In purely resistive circuit, the current is in phase with voltage. D In purely capacitive circuit, the voltage lags current.

Q1) Find the string efficiency of each line of a 3-phase is hung by a 3 strings of insulators. Each insulator has (C) Farads. The shunt capacitance of metal is 0.5 C to earth and of 0.2 C to the line, and the line a guard ring increases the capacitance to the line of the lowest insulator to 0.6 C.

INSULATORS A string of suspension consists of four (4) units.  The Voltage between each pin and earth is 0.14 of the Self-Capacitance of the unit.  The Voltage between the Line Conductor and earth is 135 KV.  Find the Voltage distribution across each unit.  Draw the diagram.

Please choose the correct answer and explain if possible. Thank you. 4. The main terminal voltage across an ON conducting SCR depends on the instantaneous main terminal current in the following way: a. They are proportional b. The voltage increases as the current increases, but no quite proportionally c. The voltage increases as the current increases, by a squared (seond power) relationship d. They are virtually non-related 5. To turn Off a conducting SCR in a dc-powered circuit, it is necessary to: a. Interrupt (stop) the gate current b. Wait for the main terminal current to fall below IHO when the supply voltage crosses through zero c. Deliver a pulse of negative gate current via the gate lead d. Place a temporary reverse bias across the SCR’s main terminals 6. In a simple RC charging circuit used for trigger-control of an SCR, a good range of adjustment of the RC time-constant is: a. 1 to 5 msec b. 1 to 30 msec c. 0.1 to 10 msec d. 2 to 25 μsec

Derives and analyse relation of capacitance for 3-core cables ? proper explanation in details

:Two circuits are arrange as shown in figure (1), (a and b) each one of them has two identical conductors, the vertical distance between each conductor in the same circuit is 1 m, the distance horizontlly between circuits is 30 cm, take 1 cm as diamter for each conductors. Derermine the inductance per km of the double circuit ? a a' b' FIGURE (1) --