The initial three-phase voltage phasors (, and ) at a bus of a power network are as shown in Case-1. Due to a disturbance, the bus voltage phasors changed in phase by a small angle , and the magnitudes remained the same as depicted in Case-2.

Which one of the following statements is correct about the zero sequence components?

For a two-phase network, the phase voltages  and  are to be expressed in terms of sequence voltages  and  as . The possible option(s) for matrix S is/are

The valid positive, negative and zero sequence impedances (in p.u.), respectively, for a 220 kV, fully transposed three-phase transmission line. From the given choices are         

(i) 1.1, 0.15 and 0.08        

(ii) 0.15, 0.15 and 0.35

(iii) 0.2, 0.2 and 0.2

(iv) 0.1, 0.3 and 0.1

Suppose  and  are a set of unbalanced current phasors in a three-phase system. The phase-B zero-sequence current  If phase-A current  and phase-C current , then  in p.u is

The series impedance matrix of a short three-phase transmission line in phase coordinates is

If the positive sequence impedance is and the zero sequence is , then the imaginary part of  (in ) is _________(up to 2 decimal places).

In an unbalanced three phase system, phase current pu, negative sequence current , zero sequence current . The magnitude of phase current  in pu is

A three phase, 100MVA, 25kV generator has solidly grounded neutral. The positive, negative and the zero sequence reactance of the generator are 0.2pu, 0.2pu and 0.05pu, respectively, at the machine base quantities. If a bolted single phase to ground fault occurs at the terminals of the unloaded generator, the fault current in amperes immediately after the fault is_______.

The sequence components of the fault current are as follows: . The type of fault in the system is

Suppose we define a sequence transformation between "a-b-c" and "p-n-o" variables as follows:

where  and k is a constant. Now, if it is given that:

 then,

The identical star connected resistors of 1.0pu are connected to an unbalanced 3 phase supply. The load neutral is isolated. The symmetrical components of the line voltages n pu are: .  If all the pu calculations are with the respective base values, the phase to neutral sequence voltages are

At a 220 kV substation of a power system, it is given that the three-phase fault level is 4000 MVA and single-line to ground fault level is 5000 MVA. Neglecting the resistance and the shunt susceptances of the system, the zero sequence driving point reactance at the bus is:  

A 3-phase transmission line supplies Δ-connected load Z. The conductor ‘c’ of the line develops an open circuit fault as shown in figure. The currents in the lines are as shown on the diagram.  The positive sequence current component in line ‘a’ will be

A three-phase alternator generating unbalanced voltages is connected to an unbalanced load through a 3-phase transmission line as shown in Figure, the neutral of the alternator and the star point of the load are solidly grounded. The phase voltages of the alternator are 10∠0°, 10∠−90°V, 10∠120°V.  The positive sequence component of the load current is

Determine the magnitudes of the symmetrical components  of the currents in a three phase (RYB) three wire system, when a short circuit occurs between R and Y phase wires, the fault current being 100A.