SGP Oral question / Switchgear and Protection Oral Question

SGP Oral question / Switchgear and Protection  Oral Question

1-What is Need for protective system? 

2- What is nature and causes of fault, types of faults, effects of faults?

3- State classification of relays & Component on relay ?

4- What is zones of protection? 

5-Explain Trip circuit of circuit breaker? 

6-Derive torque equation in induction type relay?

7-who TSM , PSM and operating time of relay? 

8-Formule for TSM , PSM and operating time of relay 

 9-For Which Circuit Breaker we used high and low resistance arc interruption? 

 10- Final derivation & definition of restriking voltage and RRRV? 

 11-In which Circuit Breaker current chopping and resistance switching is Present? 

 12-What are method to control current chopping Phenomenon? 

 13-What are the Method of arc interruption or Arc Quenching ? 

 14-What are the Classification of high voltage circuit breakers? 

 15-Full form ACB,ELCB,RCCB,VCB,SF6,OCB,ABCB. 

 16-What is GIS in India where it is implemented? 

 17-What is breaking, making capacity?

19- Where air circuit breakers are used Rating Upto? 

 20- On what factor does the performance of a circuit breaker depend? 

 21- Keeping in view the cost and overall effectiveness, the following circuit breaker is suited for capacitor bank switching? 

 22- With which of the following, a circuit breaker must be equipped for remote operation? 

 23- Circuit breakers usually operate under ? 

 24- The voltage appearing across the contacts after opening of the circuit breaker is called______voltage. ? 

 25- The time of closing the cycle, in modern circuit breakers is ? 

 26- Insulation resistance of high voltage circuit breakers is more than ? 27- Wave trap is used to trap waves of ? 

 28- Bus coupler is very essential in arrangement in ? 

 29- For cost and safety, the outdoor substations are installed for voltages above?

 30- The relay with inverse time characteristic will operate within? 

 31- Which of the following circuit breakers has high reliability and minimum maintenance? 

 32- Air blast circuit breakers for 400 kV power system are designed to operate in

 33- A fuse is never inserted in?

 34- The torque produced in induction type relay (shaded pole structure) is? 

 35-Which Relay used for

  Distance Relay  Under Frequency Relay  Differential Relay  Buchholz Relay  Translay Relay  Carrier Current ,Mho relay  Negative Sequence Relay  Directional Over current Relay  Inverse Directional Over current Relay

36-Delectric Strength of SF6 GAS OF Air ? 

 37-How to Calculate Rated Symmetrical Breaking Current ? 

 38-Explain Working and constructional features of ACB, SF6 , VCB- advantages, disadvantages and applications? 

 39-Testing Codes for Relay ? 

40-What is overreach& under reach. of Distance Relay ? 

 41- Distance Relay transient overreach is defined as? 

 42-What is merits and demerits of static relay? 

 43- Differentiate between amplitude comparators and phase comparators.? 

 44- What are the various faults to which a turbo alternator is likely to be subjected? 

 45- Mention any two disadvantage of carrier current scheme for transmission line only? 

 46- What are the causes of over speed and how alternators are protected from it? Sudden loss of all or major part of the load causes over-speeding in alternators. 

 47- Give the limitations of Merz Price protection. 

 48- Why neutral resistor is added between neutral and earth of an alternator?

 49- What are the problems arising in differential protection in power transformer and how are they overcome? 

 50- What is over fluxing protection in transformer? 

 51- Why busbar protection is needed?

 52- What are demerits of MOCB? 

 53- What is meant by electro negativity of SF6 gas? 

 54- Write the classifications of test conducted on circuit breakers. 

 55- How direct tests are conducted in circuit breakers?

56-What do you mean by Anti –Aliasing Filter, Block diagram of PMU? 

 57- What are Abnormal conditions and causes of failures in  Power Transformer Protection  3 Phase Induction Motor Protection  Synchronous Generator (Alternator) Protection 57-What do means by inrush current in Transformer ? 

 58-Which Relay is Used in loss of excitation & loss of prime mover?

 59 Derive Universe Torques Equation Impedance relay ,Reactance relay, Mho Relay?

 60-Draw R-X Diagram For Impedance relay ,Reactance relay, Mho Relay? 

 61-What do Means by Wide Area Measurement (WAM) system 

 62- Effect of arc resistance & power swing on performance of distance relay? 

 63- plot Characteristics of IDMT?