Answer / mrudang

in DG

i am answering about transfdormer
PRD (pressure relief device) using also in transformer
the function remain same
when the fault occcures in transformer , the oil pressure ,
tank mechanichal preessure affect the transformer ,
when fault occurs the oil temperature is high , and ur oil
expands and pressure will be increase

so u use the PRD for relese the pressure of transformer

Answer / dinesh (techie.dinesh@gmail.co

whenever the pressure in the transformer tank increases, the
pressure is released by PRD. PRD reduces the pressure by
splashing the oil outside the tank, i.e the PRD has a preset
value, if the value exceeds beyond the preset value, the prd
comes in action.

and when the PRD reduces the pressure, the vertical
flap/flag mounted on the PRD raises. although the pressure
is reduced, the flap wont lowered, it is used to indicate
the supervisor/operator that the pressure value has
increased. once the operator get noticed, he will manually
lower that flap

Answer / sunil guru

elobrating the above answer..
pressure relief valve is used alonge with the BUCCHOLZ RELAY..
whenever there is an incipient fault in transformer due to
oxidation the gases are produced in the oil ... which expands
the oil so to auto relief that valve we use pressure relief
valve...

regards

Based on CPI/CGPA they shortlist the candidates & than directly start Interview so there is no Written Exam or GD Only PI.Interview held @ MNNIT , ALLAHABAD On-Campus on 6th,Aug, 2007 & the Questions asked to me by Interview Board ( 4 People) are from HR/SummerTraining/BTP/Subject-core, POWER SYSTEM & MACHINE. time duration of I/V is about 15-20 Minutes. HR- Q.1 Name,hobbies & About family background ? Q2.What u know abt NTPC ?? Q3.Why u want to choose NTPC as ur Carrier's starting i.e power sector not any other Oragnisation or sector ?? Techincal Questions- Q1.What is the reason for transformer Noise ?? Q2.Which material is used for making Transformer oil & How u measure its dielectric strength & Name the test ? Q.3 Which Machine u will prefer 2 use if flammble gases are coming out at a place & why ?? Q4.What is relation b/w Transmission Lines & Communication Lines ? Q5.What is the maximum capacity Synchronus Machine & total powerGeneration in our country ? Q.6 In india Power generation is at 50Hz while in America its 60 hz ,why so ?? Advantage or disadvantage ?? Q.7 Maximum Generation Voltage in india ? Q8. What is the Voltage regulation & why its required n how much is permissible ? & causes of voltage variation ?? Q.9 Why electric shock is feel ?? n in a Electric Train why we didnt feel that ? Q.10 Have u seen/ experience of any power plant/ industry related to the power sector ? so these are the questions which not too diffcult i think was asked to me.

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