Power System Analysis Short-Circuit Load Flow and Harmonics 2nd. Edition by J.C. Das | 9781315217949 | 1439820805 | Holooly

Circuit Analysis

Power System Analysis Short-Circuit Load Flow and Harmonics

99 SOLVED PROBLEMS

Question: 6.7

Calculate the component short-circuit currents at the instant of three-phase terminal short circuit of the generator (particulars as shown in Table 6.1). Assume that phase a is aligned with the field at the instant of short circuit, maximum asymmetry, i.e., δ = 0. The generator is operating at no ...

Verified Answer:

The calculations are performed by substituting the...

Question: 6.1

Consider a 13.8 kV, 100 MVA 0.85 power factor generator. Its rated full-load current is 4184 A. Other data are Saturated subtransient reactance X”dv = 0.15 per unit Saturated transient reactance X’dv = 0.2 per unit Synchronous reactance Xd = 2.0 per unit Field current at rated load if = 3 per unit ...

Verified Answer:

From Equation 6.15, the voltage behind subtransien...

Question: 12.1

Consider a function f(x) = x³ – 2x² + 3x – 5 = 0 Find the value of x. ...

Verified Answer:

The derivative is

f^{\prime}(x)

= 3...

Question: C.2

The transformer of Example C.1 gave the following results on open circuit test: open circuit on the 4.16 kV side, rated primary voltage and frequency, input = 10 kW, and no-load current = 2.5 A. Find the magnetizing circuit parameters. ...

Verified Answer:

The active component of the current

I_{e}[/...

Question: C.1

The copper loss of a 2500 kA, 13.8–4.16 kV delta–wye connected three-phase transformer is 4 kW on the delta side and 3 kW on the wye side. Find R1, r1, r2, and r’2 for phase values throughout. If the total reactance is 5.5%, find X1, x1 x2, and x’2, assuming that the reactance is divided in the ...

Verified Answer:

The copper loss per phase on the 13.8 kV side = 4/...

Question: 12.3

Consider a transmission system of two 138 kV lines, three buses, each line modeled by an equivalent Π network, as shown in Figure 12.4a, with series and shunt admittances as shown. Bus 1 is the swing bus (voltage 1.02 per unit), bus 2 is a PQ bus with load demand of 0.25 + j0.25 per unit, and bus 3 ...

Verified Answer:

First, form a Y matrix as follows:

\overlin...

Question: 8.2

Calculate the fault current contributions of the following asynchronous machines, directly connected to a bus, using ANSI and IEC methods. Calculate first-cycle (IEC peak) currents and the interrupting (breaking) currents at contact parting times of two and three cycles, 60 Hz basis, and IEC ...

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These results of ANSI calculations are shown in Ta...

Question: A.2

Find the characteristic equation of the matrix A = |1 4 2 3 2 -2 1 -1 2| and then the inverse of the matrix. ...

Verified Answer:

The characteristic equation is given by

\le...

Question: 2.1

Consider a balanced three-phase delta load connected across an unbalanced three-phase supply system, as shown in Figure 2.7. The currents in lines a and b are given. The currents in the delta-connected load and also the symmetrical components of line and delta currents are required to be calculated ...

Verified Answer:

The currents in delta windings are

I_{AB} =...

Question: 6.5

Consider the generator data of Example 6.1. Calculate the direct and quadrature axis components of the currents and voltages and machine voltage E when the generator is delivering its full-load rated current at its rated voltage. Also calculate all the angles shown in the phasor diagram, ...

Verified Answer:

The generator operates at a power factor of 0.85 a...

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