What are the problems in station operation due to grid under frequency?

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What are the problems in station operation due to grid under frequency?

asked Nov 17, 2021 by anonymous

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What are the problems in station operation due to grid under voltage?

Description : What are the problems in station operation due to grid under voltage?

Last Answer : a) All the HT motors overloaded. b) VAR load increases on generator leads to heating up of rotor c) Stator current increases for same power export leads to stator over heating.

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Description : Operation carried out in Thermal power station?

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Description : What are the operation carried out in Thermal power station?

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Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation? A. The motor will overspeed. B. The motor will run at a reduced speed. C. A time delay will stop the motor. D. The winding will burn out.

Description : Which of the following problems will most likely occur if the starting winding of a split-phase induction motor failed to cutout once the motor was in continuous operation? A. The motor will overspeed. B. The ... reduced speed. C. A time delay will stop the motor. D. The winding will burn out.

Last Answer : Answer: D

Write the most important mode of operation of power system and mention the major problems encountered with it.

Description : Write the most important mode of operation of power system and mention the major problems encountered with it.

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As shown in the illustrations, most console schematic diagram sheets have letters and/or numbers placed across the top and numbers along the side boarders. The purpose of these markings is to ________________. EL-0099 A. make a grid which, together with the sheet numbers, can direct the engineer to any location in the prints B. section-off the book so that each console function is marked with the same letter/number combination C. allow a record to be kept of how often a particular component represented on that page has been tested D. indicate, by punching a small hole over a letter and number, what month and year that particular page was redrawn

Description : As shown in the illustrations, most console schematic diagram sheets have letters and/or numbers placed across the top and numbers along the side boarders. The purpose of these markings is to ... small hole over a letter and number, what month and year that particular page was redrawn

Last Answer : Answer: A

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Last Answer : Answer: C

Explain the behavior of generator when operating alone and operating parallel with grid.

Description : Explain the behavior of generator when operating alone and operating parallel with grid.

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Transformers are used onboard ships with AC generators to _____________. A. change frequency B. increase power output to modulating frequency controllers C. decrease power output to modulating frequency controllers D. permit higher voltage for electric motor operation and low voltage for lighting circuits

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Last Answer : Answer: D

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Description : How does change in frequency affect the operation of a given transformer?

Last Answer : a) Iron loss .........increases with a decrease in frequency. A 60-Hz transformer will have nearly 11% higher losses when worked on 50Hz instead of 60 Hz. However, when a 25-Hz ... ....since total loss is greater at a lower frequency, the temperature is increased with decrease in frequency.

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Description : Explain the operation of variable frequency transformer?

Last Answer : A. A variable frequency transformer is used to transmit electricity between two asynchronous alternating current domains. It is a double fed electric machine resembling a vertical shaft hydroelectric ... adjustable phase shifting transformer. It allows control of the power flow between two networks.

How does change in frequency affect the operation of a given transformer?

Description : How does change in frequency affect the operation of a given transformer?

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Last Answer : Answer: C

The illustration shows a fluorescent light fixture. The ends of the lamp alternately glow and become dark, but the tube will not light. The most probable cause is that ____________. EL-0081 A. component 'D' is loose and due to the ship's vibrations makes and breaks contact B. the power system's voltage is fluctuating in and out of the range necessary for proper operation C. component 'A' is shorted and therefore unable to produce the high voltage required to start the lamp D. component 'B' contacts are opening and closing thus prohibiting sufficient current flow

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Magnetic controller contacts may become welded together during operation due to _____________. A. an open coil B. low contact pressure C. excessive ambient temperature D. excessive magnetic gap

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During start-up of the circuit shown in the illustration, it is noted that the ends of component 'C' alternately glow and become dark without the tube illuminating. The most probable cause for this is that ____________. EL-0081 A. component 'D' is loose and due to the ship's vibrations makes and breaks contact B. the power system's voltage is fluctuating in and out of the range necessary for proper operation C. component 'A' is shorted and therefore unable to produce the high voltage required to start the lamp D. component 'B' contacts are opening and closing thus prohibiting sufficient current flow

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Description : What is an under frequency relay?

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Last Answer : b. The DME is trying to lock onto range

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Last Answer : a. Try another appropriate frequency

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Last Answer : c. Never

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A super heterodyne AM receiver is tuned to a station operating at 1200 KHz .Find local oscillator frequency and image frequency.

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Description : Before any work on electrical or electronic equipment is performed, which of the following precautions should be carried out? A. De-energize the applicable switchboard bus. B. Bypass the interlocks. C. ... supply circuit breaker in the open position. D. Station a man at the circuit supply switch.

Last Answer : Answer: C

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Last Answer : Answer: B

In the system shown in the illustration, the station at section I is unable to signal any other station nor is any other station able to signal the station in section I. The station can, however, ring itself by proper positioning of its selector switch. EL-0093 A. The selector switch is grounded at the problem station diverting current from the other stations' ringing devices. B. There is an open between terminal 'C' of the problem station and the multi-conductor cable to the other stations. C. The contacts to the left of component 'B' are stuck closed allowing only a single station to respond to itself. D. The switch at component 'C' is stuck open.

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Last Answer : Answer: B

Sections 'I', 'II' and 'III' of the circuit shown in the illustration are 'station numbers' _____________. EL-0093 A. 2, 4 and 6 B. 1, 2 and 3 C. 3, 5 and 8 D. 1, 2 and 6

Description : Sections 'I', 'II' and 'III' of the circuit shown in the illustration are 'station numbers' _____________. EL-0093 A. 2, 4 and 6 B. 1, 2 and 3 C. 3, 5 and 8 D. 1, 2 and 6

Last Answer : Answer: D

anonymous · Answer 1 · 2021-11-17T09:22:44+0000

a) Turbine having under frequency limitation, house load happen if < 48 Hz

b) Due to under frequency PHT flow reduces, therefore reactor power reduces, generator power reduces

c) If frequency is less than 48 Hz DG cannot be synchronised to grid, therefore DG kept on isolation running

d) GT overfluxing.

What are the problems in station operation due to grid under frequency?

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