The parameters of Transmission line are R = 50 Ω/ km, L= 1mH/km ,C = 0.1µf/km, G = 2µV/km. calculate characteristic impedance.

Description : Calculate the characteristics impedance for a transmission line having L=0.5 mH/Km, C=0.08 µF and negligible R and G.

Answer : L=0.5 mH/Km C=0.08 µF

Description : A telephone cable has following primary constants per loop kilometer ,R=30Ω, L=20mH,C=0.06µF,G=0.If the applied signal has an angular frequency of 5000 rad/sec.., Determine (i) Characteristics impedence (ii) Attenuation constant

Answer : A telephone cable has following primary constants per loop kilometer ,R=30Ω, L=20mH,C=0.06µF,G=0.If the applied signal has an angular frequency of 5000 rad/sec.., Determine (i) Characteristics impedence (ii) Attenuation constant

Description : 220kV three phase transmission line is 60 km long. The resistance is 15 Ohms per phase and the inductance is j 30 Ohms. 1- Calculate : voltage regulation, TL line power losses and efficiency when ... for 0.85, calculate zise of the required capacitor and the same parameters which were in part 1

Description : A load of 200 ohm is used to match 300 ohm transmission line to achieve SWR=1. Find out the required characteristic impedance of a quarter of a quarter wave transformer connected directly to the load.

Answer : Solution :

Description : Calculate characteristic impedance (Zo) for parallel and co-axial cables.

Answer : characteristic impedance for parallel cable characteristic impedance for co-axial cable Zo =Characteristic impedance D=Diameter of outer conductor d= Diameter of inner conductor E=Dielectric constant

Description : A balanced Delta connected load supplied with 440 V 50 Hz three phase AC supply has R=10 Ohm and L=0.6 mH in is each arm. Calculate line and phase current, active power.

Description : For transmission line, the incident voltage Ei = 6V, and Er = 3V. Calculate: (1) Reflection coefficient (2) Standing wave ratio

Answer : (1)Reflection coefficient (2) Standing wave ratio (1)Reflection coefficient Reflection coefficient R=Er/Ei =3/6 R=0.5 (2) Standing wave ratio SWR=Ei+Er/Ei-Er =6+3/6-3 SWR =3

Description : For a transmission line, the incident voltage. Ei = 6V and Er =2V ,Calculate: (i) Reflection Coefficient (ii) SWR

Answer : Reflection Coefficient(K) = Er / Ei = 2V / 6V K = 0.333 SWR = 1+K / 1- K = 1+0.333 / 1-0.333 = 1.333 / 0.667 SWR= 1.998

Description : The input impedance of a short circuited loss less transmission line of characteristic impedance 50 Ohm is

Answer : The input impedance of a short circuited loss less transmission line of characteristic impedance 50 Ohm is may be capacitive or inductive depending on the length of the line

Description : a) For a transmission line, Find SWR and reflection coefficient R if, i. There is no reflected voltage. ii. Reflected voltage and incident voltage is equal. iii. If reflected voltage=20V and incident voltage=10V. iv. If reflected voltage=10V and incident voltage =20V.

Answer : reflection coefficient R=Vr/Vi i. There is no reflected voltage. i.e,Vr=0 R=0 SWR= 1+R/1-R=1 ii. Reflected voltage and incident voltage is equal. Vr=Vi; R=1 SWR= 1+R/1-R=1+1/1-1=infinity iii. If reflected ... and incident voltage =20V. Vr=10 and Vi=20 R=10/20=0.5 SWR= 1+R/1-R=1+.5/1-.5=3

Description : For a transmission line open circuit and short circuit impedances are 20 Ω and 5 Ω. Then characteristic impedance is: (1) 100 Ω (2) 50 Ω (3) 25 Ω (4) 10 Ω

Answer : For a transmission line open circuit and short circuit impedances are 20 Ω and 5 Ω. Then characteristic impedance is: 10 Ω

Description : A three phase 50 Hz, 400 kV transmission line is 300 km long. The line inductance is 0.97 mH/km per phase and capacitance is 0.0115 mF/km per phase. Assume a loss less line. Determine the line wavelength (a line phase constant). (A) 1250 km (B) 6578 km (C) 4990 km (D) 2445 km

Description : A transmission line of 200 km has a certain A, B, C and D parameters. If the length is reduced to 60 km

Answer : A transmission line of 200 km has a certain A, B, C and D parameters. If the length is reduced to 60 km A increases, B decreases

Description : A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is: (1) 4000 Ω (2) 400 Ω (3) 40 Ω (4) 4 Ω

Answer : A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is: 400 Ω

Description : Draw waveform for standing waves on an open and shorted line. Prove that impedance is inverted at every quarter wavelength interval.

Answer : Waveform- Explanation When the transmission line is short circuited voltage is zero and current is maximum.The variation is according to the wavelength. When the ... The pattern repeats for every half wavelength. Thus impedance is inverted at every quarter wavelength interval.

Description : A transmission line is terminated at its characteristic impedance. The reflection coefficient is (a) 1 (b) –1 (c) 0 (d) ∞

Answer : A transmission line is terminated at its characteristic impedance. The reflection coefficient is 0

Description : Define the transmission line? Draw it‟s general equivalent circuit.

Answer : Transmission line: A conductor or conductors designed to carry electricity or an electrical signal over large distances with minimum losses and distortion. Equivalent circuit:

Description : Draw general equivalent circuit of transmission line.

Answer : Fig. General Equivalent circuit of transmission line

Description : State and explain the losses in transmission line.

Answer : Losses in Transmission Line:- There are three ways in which energy, applied to a transmission may desperate before reaching the load. They are 1) Radiation Losses:- Its occurs when a ... down voltage of the dielectric insulator. Generally when corona occurs, the transmission line is destroyed.

Answer : If R, L and C are the parameters of a resistor then the condition for the resistor to be non-inductive is L = CR2 .

Description : A transmission line has 1 P.0 impedance on a base of 11 KV, 100 MVA. On a base of 55 KV. it will have a P.0 impedance of

Answer : A transmission line has 1 P.0 impedance on a base of 11 KV, 100 MVA. On a base of 55 KV. it will have a P.0 impedance of 0.02 P.U

Description : A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is?

Answer : A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is 0.6 lagging.

Description : Voltages phasors at the two terminals of a transmission line of length 70 km have a magnitude of 1.0 per unit but are 180 degree out of phase. Assuming that the maximum ... Pilot relaying system with directional comparison scheme (D) Pilot relaying system with segregated phase comparison scheme

Description : A 220 kV, 3 phase transmission line is 60 km long. The resistance is 0.15 ohm / km and the inductance is 1.4 mH / km. Use the short line model to find the power at the sending end when the line is supplying a three ... at 0.8 pf lagging at 220 kV. (A) 5.58MW (B) 80MW (C) 85.58MW (D) 74.42 MW

Description : An antenna has a radiation resistance of 72 Ω a loss resistance of 8 Ω and a power gain of 16. Find efficiency and directivity.

Answer : An antenna has a radiation resistance of 72 Ω a loss resistance of 8 Ω and a power gain of 16. Find efficiency and directivity.

Description : The driving point impedance with poles at ω = 0(zero) and ω = ∞ (infinity) must have the (a) s term in the denominator and an excess term in the numerator (b) s term in the ... the numerator and denominator (d) s term in the denominator and equal number of terms in the numerator and denominator

Answer : The driving point impedance with poles at ω = 0(zero) and ω = ∞ (infinity) must have the s term in the denominator and an excess term in the numerator

Description : For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is

Answer : For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is 0.707 lead

Description : How quarter wave transformer is used for impedance matching.

Answer : In all applications of transmission line, it is required that the load be matched to line, Which requires tuning out the unwanted load reactance and the transformation of resulting impedance to the required value ... Step down transformer If ZL <Zo then it acts as a Step up transformer

Description : Explain the use of baluns for impedance matching.

Answer : Balun stands for Balance to unbalance. It can also be used to connect the unbalanced transmission line to a balance load such as antenna. It consist of special type of transformer with an unbalanced primary ... matching. Its input is 300-75ohm. It consist of two quarter wave length.

Answer : In an R-C-L series circuit, during resonance, the impedance will be minimum.

Description : If the RF transmission is terminated in its Characteristic impedance Z, which of the following statements is wrong : a. The input impedance of transmission line becomes Zc. b. The transmission line acts as an infinite long transmission line. c. The VSWR becomes one d. The VSWR becomes infinite

Description : Write equation of resultant impedance in R-L circuit.

Answer : The equation of resultant impedance in R-L circuit

Description : The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is: (1) 25 ohm (2) 50 ohm (3) 75 ohm (4) 100 ohm

Answer : The magnitude of the open-circuit and short circuit input impedance of a transmission line are 100 ohm and 25 ohm respectively. The characteristic impedance of line is 25 ohm.

Description : A 10A DC Ammeter has a resistance of 0.1 Ω is to be extended to 50 A, the required shunt wire is A) Manganin wire of 20 m Ω B) Constantan wire of 20 m Ω C) Manganin wire of 25 m Ω D) Constantan wire of 25 m Ω

Answer : A 10A DC Ammeter has a resistance of 0.1 Ω is to be extended to 50 A, the required shunt wire is Manganin wire of 25 m Ω

Description : A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is (1) 10 (2) 2 (3) 1 (4) Infinity

Answer : A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is Infinity.

Description : A moving coli ammeter has a fixed shunt of 0.02 Ω with a coil circuit resistance of R=1 kΩ and needs potential of 0.5 V across it for full scale deflection. Calculate the value of shunt to give full scale deflection when the total current is 10 A. (1) 0.05 Ω (2) 0.005 Ω (3) 0.5 Ω (4) 0.0005 Ω

Description : Discuss the effect of transmission line parameters on the performance of transmission line .

Answer : Following are the effect on performance of transmission line: 1. Due to resistance (R), voltage drop in transmission line produces 2. Due to resistance (R), copper losses in ... voltage regulation of transmission line gets affected 7. Also power factor of transmission line gets affected

Description : State line parameters of transmission line.

Answer : Following are the of Line parameters of transmission line: 1. Resistance 2. Inductance 3. Capacitance

Description : The standing wave ratio of a 75 Ω transmission line used to feed a 300 Ω resistive load will be _____.

Answer : The standing wave ratio of a 75 Ω transmission line used to feed a 300 Ω resistive load will be 4.

Description : State and explain the concept of transmission bandwidth.

Answer : Bandwidth is defined as the portion of the electromagnetic spectrum occupied by a signal We may also define the bandwidth as the frequency range over which as information signal is transmitted. Bandwidth is the ... to 15 KHZ. Therefore the bandwidth is(f2-f1) BW= f2 - f1= 15000-20=14980Hz

Description : Define critical frequency w.r. to wave propagation.

Answer : Define critical frequency w.r. to wave propagation.

Description : Using the data from 16, calculate the correlation coefficient. a. r = 0.490 b. r = 0.985 c. r = 0.971 d. r = 0.240

Answer : b. r = 0.985

Description : Describe line of sight propagation in brief.

Answer : Line of sight propagation or Space wave propagation:- Explanation:- Space wave propagation of electromagnetic energy includes radiated energy that travels in the lower few miles of Earth's ... waves reflected by Earth's surface as they propagate between the transmit and receive antennas.

Description : Calculate the rate of heat transfer by radiation from an unlagged steam pipe, 50 mm o.d. at 393K to air at 293K emissivity e = 0.9.

Answer : Rate of heat transfer by radiation Assume length of pipe = 1 m

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Description : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is (A) sinusoidal current (B) constant dc current (C) continuous rectangular pulses (D) alternating rectangular pulses

Answer : In a 230 V, 50 Hz single-phase SCR bridge converter operating at a firing delay angle, α and with large R-L load, the input source current is alternating rectangular pulses

Description : A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9

Answer : A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9

Description : A loss less transmission line having Surge Impedance Loading (SIL) of 2280 MW is provided with a uniformly distributed series capacitive compensation of 30%. Then, SIL of the compensated transmission line will be (A) 1835 MW (B) 2280 MW (C) 2725 MW (D) 3257 MW

Answer : A loss less transmission line having Surge Impedance Loading (SIL) of 2280 MW is provided with a uniformly distributed series capacitive compensation of 30%. Then, SIL of the compensated transmission line will be 2280 MW

Description : When the load on a transmission line is equal to the surge impedance loading (a) The receiving end voltage is less than the sending end voltage (b) The sending end voltage is less than the ... is more than the sending end voltage (d) The receiving end voltage equal to the sending end voltage

Answer : When the load on a transmission line is equal to the surge impedance loading The receiving end voltage equal to the sending end voltage

Description : Surge impedance of overhead transmission line is normally in the order of (a) 1- 5 ohms (c) 300 - 500 ohms (b) 20 - 30 ohms (d) 300000 - 500000 ohms

Answer : Surge impedance of overhead transmission line is normally in the order of 300 - 500 ohms