List of top Power Systems Questions

The geometric mean radius of a conductor, having four equal strands with each strand of radius ‘r’, as shown in the figure below, is
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

A 3-Bus network is shown. Consider generators as ideal voltage sources. If rows 1, 2 and 3 of the \(Y_{\text{Bus}}\) matrix correspond to Bus 1, 2 and 3 respectively, then \(Y_{\text{Bus}}\) of the network is 

In the figure shown, self-impedances of the two transmission lines are 1.5j p.u each, and $Z_m = 0.5j$ p.u is the mutual impedance. Bus voltages shown in the figure are in p.u. Given that $\delta > 0$, the maximum steady-state real power that can be transferred in p.u from Bus-1 to Bus-2 is 

Two generators have cost functions with incremental-cost characteristics: 
\[ \frac{dF_1}{dP_1} = 40 + 0.2 P_1, \frac{dF_2}{dP_2} = 32 + 0.4 P_2 \] They must supply a total load of 260 MW. Find the optimal generation (economic dispatch) ignoring losses. 
 

Suppose \(I_A, I_B\) and \(I_C\) are a set of unbalanced current phasors in a three-phase system. The phase-B zero-sequence current is \(I_{B0} = 0.1\angle 0^\circ\) p.u. If the phase-A current \(I_A = 1.1\angle 0^\circ\) p.u and phase-C current \(I_C = (1\angle 120^\circ + 0.1)\) p.u, then \(I_B\) in p.u is
The dimension of the sub-matrix $M$ in the Newton-Raphson Jacobian is \(\underline{\hspace{2cm}}\).