Job interview or viva Topics for Electrical Engineers (Part-6)

Electrical engineering interview question and answers:

Job interview or viva Topics for Electrical Engineers (Part-6)

21. Swing equation: 

During the transient state of the synchronous machine, the relation between the accelerating power and angular acceleration is called swing equation.

M (d²δ/dt²) = Ps – Pe

Here,

M = angular momentum of the rotor,

Ps = mechanical power input,

Pe = electrical power output,

δ= load angle,

t = time,

22. Swing Curve: 

The graph which shows the relation between δ versus t is called swing curve. These graphs provide the stability information. This swing curve information is useful for understanding the adequacy of relay protection in the power station. This information helps to solve the faults before one or more machines become unstable.

23. Unsymmetrical faults: 

The unbalanced conditions of the system are called unsymmetrical faults. If an unbalanced connection is attached at any point of the balanced system, then this point is called the fault point of the system. This unsymmetrical fault has normally two types:

1. Shunt fault. 

2. Series fault.

24. Shunt Fault:

An unbalanced shunt fault is an unbalanced condition between phases and ground or, an unbalance between phases.

25 Classification of shunt fault:

In a 3-phase system the shunt fault are as follows,

·        Single line to ground fault (LG).

·        Line to line fault (LL).

·        Double line to ground fault (LLG).

·        Three phase short Circuit fault (LLL).

·        Three phase to ground fault (LLLG).

Here,

·        LG, LL, LLG ---- unsymmetrical faults.

·        LLL, LLLG ---- symmetrical faults.

26. Series fault:

The unbalance in the line impedances is known as series fault.

-- - - - -- --- - -- - - -- - - - -- -  -- - - - - -  -- - - - -- - - - - - - - - 

We will give more important questions and answers for electrical engineering interview very soon. Please subscribed to RSS feed or Email feed. We need your help for the betterment of the site. Please give comments and tell us what’s your opinions and needs from us. We will try to give your required things.

vivasolve.blogspot.com