# Overhead system can be designed for operation up to?

Overhead system can be designed for operation up to 400 kV.

## Related questions

Description : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... Current will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

Answer : What would happen if a power transformer designed for operation on 50 Hz (frequency) were connected to a 500 Hz (frequency) source of the same voltage:  (A) Eddy Current and Hysteresis losses will be ... will be too much high  (C) Transformer may start to smoke and burn  (D) No effect

Answer : Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.

Description : Why ACSR conductor is used for overhead lines?

Answer : It has high tensile strength

Description : Draw and explain integrated duration curve used in system operation.

Answer : Diagram of integrated duration curve used in system operation: Explanation:  Integrated duration curve is obtained from load duration curve. It is drawn in between load on Y-axis in KW/MW and the X- ... a particular time of a day can also be shown on a curve which is called as mass curve.

Answer : Relays can be designed to respond to changes in resistance, reactance or impedance voltage and current, light intensity, temperature.

Description : Explain the lighting scheme to be designed for each of the following: i) Special ward in hospitals ii) Dentist’s Cabin

Answer : i) Special ward in hospital: For the patients in the wards, lighting should create a cozy and pleasant atmosphere. Lighting in the wards should be planned in such a way that it meets the specific ... we use such as cements and bonding agents that we use to restore your teeth back to health.

Description : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :  (A) less than 66 kV (B) lie between 66 kV and 110 kV (C) more than 165 kV (D) lie between 110 kV and 165 kV

Answer : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : lie between 66 kV and 110 kV

Answer : Overhead lines for power supply to tramcars are at a minimum height of 10 m.

Answer : D.C. generators are normally designed for maximum efficiency around full-load.

Answer : Generators for peak load plants are usually designed for maximum efficiency at 50 to 75 percent full load.

Description : State properties of conductor material used for overhead conductor.

Answer : Following are the properties of conductor material:-   1. High conductivity :- Material should have high conductivity 2. High mechanical strength:- Material should have sufficiently high mechanical strength ... available & less costly. 9. Scrap Value: - Material should have high scrap value.

Description : A circuit breaker is designed to protect an electrical circuit from damage caused by :  (A) Over load (B) Short circuit (C) Over current (D) All of the above

Answer : A circuit breaker is designed to protect an electrical circuit from damage caused by :  (A) Over load (B) Short circuit (C) Over current (D) All of the above

Answer : The efficiency of a properly designed synchronous motor will usually fall in range 85 to 95%.

Answer : An efficient and a well designed protective relaying should have good selectivity and reliability, economy and simplicity, high speed and selectivity.

Description : Differentiate between overhead transmission and underground transmission.

Answer : Points Overhead line  Underground cable Capital cost  Less More Erecting cost  Less More Time require for completion of work Less More Flexibility More ... Space consumed Space consumed  No space consumed Appearance Not good  Very good

Description : Why are overhead transmission lines not insulated?

Answer : Insulators are useful to help separate electrical conductors when they come into physical contact. Overhead Transmission Lines Are Not Insulated: The overhead transmission line is carrying extreme high voltage and ... a whole lot of thick insulation to absorb the heat produced by such high voltage.

Description : Why underground service connections are service connections are costly than overhead service connection

Answer : Reason: Underground service connection is given by underground cable. This cable is costly than bare conductor. Sometimes cable trench is required for cable laying, which requires additional cost. So underground service connections are costly than overhead service connection.

Description : Define service connection and state types connection and state types of overhead service connection

Answer : Service Connection:- It is the input conductor or wire which is carried out from supply company (authorities) pole to consumers' main board or premises. Types of overhead service ...  1. Overhead service connection with Bare conductor 2. Overhead service connection with weather proof cable

Description : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is

Answer : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is terminated into a resistance equal to surge impedance of the line

Description : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO

Answer : Which of the following thyristors can be used for high frequency of operation? A) TRIAC B) DIAC C) SCR D) GTO

Answer : The underground system cannot be operated above 66 kV.

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

Description : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm

Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm

Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

Answer : For the parallel operation of two or more D.C. compound generators, we should ensure that series fields of all generators should be either on positive side or negative side of the armature.

Answer : Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers:  1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.

Description : Explain the basic operation of an oscilloscope with necessary diagram for each section in detail.

Description : vertical deflection system and explain its operation.

Answer : The main function of the vertical deflection system , is to provide an amplified signal of proper level to derive the vertical deflection plates without any distortion. For amplification of the ... suppression, reduced nonlinear effects because none of the plates are at ground potential.

Description : State jumping operation.

Answer : Jumping up operation: This process makes metal shorter and thicker and carried out at near welding temperature. Metal can be either thickened at the ends of bars or swollen in the center.

Description : With neat sketch explain four modes of operation of a TRIAC?

Answer : Modes of operation of a TRIAC: There are four different operating modes of TRIAC:  1) MT2 and gate are positive with respect to terminal MT1(Mode1) : Here terminal MT2 is positive ... junction P2-N2 is forward biased, current carriers are injected and therefore, the TRIAC is turned on.

Description : What is PLL? Explain its operation with a block diagram.

Answer : PLL - A phase-locked loop or phase lock loop is a control system that generates an output signal whose phase is related to the phase of an input signal Block diagram  ... to the input frequency. The phase - locked loop goes through three states free running capture and phase lock.

Description : Draw & explain operation of phase detector.

Answer : In phase detector, the op-Amp basically acts as a zero crossing detector. If a sine wave is applied at the i/p, we get square wave at the op-Amp o/p (at point ... to two channel of the CRO. The time duration between the pulses corresponding to voltages represent the phase between them.

Description : State the principle of operation of d.c. motor.

Answer : When a current carrying conductor is placed in a magnetic field, the conductor experiences the force. The magnitude of force is given by F = BIL newton  where F – Force   B – maximum flux density   I – Current   L – Length of conductor

Description : operation of DSO with block diagram.

Answer : The input is amplified and attenuated with input amplifiers. The output of the input signal amplifiers feeds an analog to digital converter (ADC). There are numbers of ADC available. But the selection of ADC ... view the display on the CRT, the data from memory is reconstructed in analog form.

Description : operation of ramp type DVM.

Answer : This is given to an input comparator which will compare two signals and generates the output. One input to the input comparator is from the input and another input is from the ramp. This input voltage and ... ground and output is given. This output will stop the flow of purchase from clock

Description : operation of half wave rectifier type AC Voltmeter.

Answer :  Half-wave Rectifier Voltmeter The d'Arsonval meter movement only responds to the average or dc value of the current through the moving coil. In order to measure alternating ... ) input voltage signal alternating signal needs to be rectified first by using diode rectifier to produce

Description :  operation of whetstone bridge.

Answer : A Wheatstone bridge is widely used to measure the electrical resistance. This circuit is built with two known resistors, one unknown resistor and one variable resistor connected in the form of bridge. ... using a Wheatstone Bridge the unknown electrical resistance value can easily measure.

Description : State principle of operation of piezo-electric transducer. State its application.

Answer : The piezoelectric element used for converting mechanical movement into electric signals. The mechanical deformation generates charges and this charge appears as a voltage across the electrodes.  ... destructive test (NDT) equipments 6. Piezoelectric materials are used in ultrasonic transducers.

Description : Explain the operation of UPS with a neat block diagram.

Answer : Uninterruptible-Power-Supplies (UPS): A block diagram of UPS system is shown in figure. It essentially consists of four major components: i)Rectifier (or battery charger) ii) ... . Due to fast action requirement, transfer switch can be implemented by fast acting semiconductor devices.

Description : Describe principle of operation of Doppler type ultrasonic flow meter with diagram.

Answer : Diagram: Working:  The flow meter consists of a crystal transducer mounted outside the pipe in which flow is to be measured. This transducer is a piezoelectric crystal which ... , so the frequency of the reflected wave is shifted to particle velocity, according to Doppler principle.

Description : Explain the operation of advanced gas cooled reactor.

Answer : Operation:- Carbon dioxide or Helium is the gas used for transferring the heat produced form the reactor core to the Heat exchanger. The gas is pumped through the reactor core at high pressure. In heat ... The AGR was designed to have a high thermal efficiency 40 %. Steam pressure is 162 Kg/cm2

Description : Describe the operation of N channel enhancement type MOSFET with diagram.

Answer : As its name indicates, this MOSFET operates only in the enhancement mode and has no depletion mode. It operates with large positive gate voltage only. It does not conduct when the ... of charge carriers attracted to the positive gate. Thus drain current is controlled by the gate potential.

Description : Draw diagram of class A push-pull amplifier and explain its operation.

Answer : Class A Push-pull Amplifier: The circuit diagram of class A push-pull amplifier is as shown in the fig.(a). Operation: The resistors R1 and R2 along with Vcc provide the dc biasing so as ... Vcc is applied to the collectors of transistors Q1 and Q2 through the centretapped output transformer.

Description : Describe operation of N-channel JFET

Answer : Operation of N-channel JFET  1) When VGS = 0 volt: When a voltage is applied between the drain and source with a DC supply voltage VDD with VGS = 0 V, the electrons flow from source ... to zero. The gate to source voltage at which current reduces to zero is called as pinch-off voltage.

Description : What is photodiode? Draw the symbol and explain operation of photodiode.

Answer : A photodiode is a light detector that converts light into an electrical current. A photodiode is a semi-conductor device, with a p-n junction and an intrinsic layer between p and n layers ... current is independent of reverse bias voltage. Reverse current is mostly depends on the light intensity.

Description : A four -quadrant operation requires two full converters connected in  (1) Series (3) Back to back (2) Parallel (4) Series Cascade

Answer : A four-quadrant operation requires two full converters connected in Parallel

Description : The operation of a ramp type Digital Voltmeter is based on the principle of (A) Voltage-to-current conversion. (B) Voltage-to-time conversion. (C) Current-to-time conversion. (D) Current-to-frequency conversion.

Answer : The operation of a ramp type Digital Voltmeter is based on the principle of Voltage-to-time conversion.

Description : Enlist the different modes of operation of electronic counters and explain any two modes in details.

Description : Describe the basic SHA operation with the help of its four mode specifications.

Answer : Sample-and-hold amplifier (SHA) is a unity gain amplifier with a mode control switch where the input of the amplifier is connected to a time-varying signal. A trigger pulse at the mode control switch ... but other forms, such as optical and mechanical forms, are possible. Also denoted S/H.

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