Interview Questions and Answers

Unsymmetrical Fault Analysis Interview Questions and Answers: 1. Draw the sequence network for single line-to-ground fault without fault impedance. Ans. 2. Draw the sequence network connections corresponding to L-L fault at a bus. Ans. 3. How are sequence networks interconnected in the case of L-L-G fault ? Ans. Three symmetrical component sequence networks are connected […]

Symmetrical Fault Analysis Interview Questions and Answers: 1. What is meant by fault level ? Ans. When fault occurs at a point in a power system, the corresponding MVA is referred to as the fault level at that point. 2. What are current limiting reactors ? Ans. Current limiting reactors are inductive coils having large

Symmetrical Components Interview Questions and Answers: 1. What do you mean by Fortescue theorem. Ans. According to Fortescue theorem, any unbalanced three-phase system of currents, voltages or other sinusoidal quantities can be resolved into three balanced systems of phasors which are called symmetrical components of the original unbalanced system. Such three balanced systems constitute three

Representation of Power System Components Interview Questions and Answers: 1. What is meant by percentage reactance ? Ans. Percentage reactance can be defined as the voltage drop across the given reactance expressed as percentage of normal voltage when carrying full-load current pertaining to normal rating. 2. Which of the electrical quantities are chosen as base

Switchgear and Protection Interview Questions and Answers: 1. What is meant by short circuit ? Ans. When conductors of different phases come into contact with each other in a power line, power transformer, or any other circuit element, part of the impedance of the system is shunted out of the circuit, a large current flows

High Voltage DC Transmission Interview Questions and Answers: 1. Why is voltage regulation better in case of dc transmission ? Ans. Because of absence of inductance in dc systems. 2. Why there is no limit on the length of the cable for dc system while it is in case of ac system ? Ans. Because

High Voltage AC Transmission Interview Questions and Answers: 1. What are the transmission voltages that are used in India ? Ans. 33, 66, 110, 132, 220 and 400 kV. 765/800 kV is also in used in India. 2. What are the advantages of adopting extra high voltage/ultra high voltage for transmission of ac electric power

Interference of Power Lines Interview Questions and Answers: 1. How do power lines cause interference with neighbouring communication lines ? Ans. The transmission lines transmit bulk power at relatively higher voltages and, therefore, these lines give rise to electromagnetic and electrostatic fields of sufficient magnitude which induce currents and voltages in the neighbouring communication lines.

Insulation Resistance of a System Interview Questions and Answers: 1. What are the faults that are likely to occur in cables ? Ans. The faults which are likely to occur in cables are open circuit, short circuit and ground faults. 2. What is meant by ‘ground fault’ in cables ? Ans. When the current starts

AC Distribution Interview Questions and Answers: 1. What is primary distribution system and what is normal operation voltage of primary distribution ? Ans. Primary distribution system is that part of the distribution system which operates at voltages such as 3.3, 6.6 or 11 kV. The normal operation voltage of primary distribution is 11 kV. 2.