A 1000-MVA 20-kV, 60-Hz three-phase generator is connected through a 1000-MVA 20-kV A/345-kV Y transformer to a 345-kV circuit breaker and a 345-kV transmission line. The generator reactances are X = 0.17, X, = 0.30, and X4 = 1.5 per unit, and its time constants are T = 0.05, T, = 1.0, and TA = 0.10 s. The transformer series reactance is 0.10 per unit; transformer losses and exciting current are neglected. A three-phase short-circuit occurs on the line side of the circuit breaker when the gener- ator is operated at rated terminal voltage and at no-load. The breaker interrupts the fault 3 cycles after fault inception. Determine (a) the subtransient current through

A 1000-MVA 20-kV, 60-Hz three-phase generator is connected through a 1000-MVA 20-kV A/345-kV Y transformer to a 345-kV circuit breaker and a 345-kV transmission line. The generator reactances are X = 0.17, X, = 0.30, and X4 = 1.5 per unit, and its time constants are T = 0.05, T, = 1.0, and TA = 0.10 s. The transformer series reactance is 0.10 per unit; transformer losses and exciting current are neglected. A three-phase short-circuit occurs on the line side of the circuit breaker when the gener- ator is operated at rated terminal voltage and at no-load. The breaker interrupts the fault 3 cycles after fault inception. Determine (a) the subtransient current through

Power System Analysis and Design (MindTap Course List)

6th Edition

ISBN:9781305632134

Author:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Publisher:J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma

Chapter11: Transient Stability

Section: Chapter Questions

Problem 11.19P

See similar textbooks

Similar questions

The amplitude of the sinusoidal symmetrical ac component of the three-phase short-circuit current of an unloaded synchronous machine decreases from a high initial value to a lower steady-state value, going periods through the stages of __________ and ________ periods.
Consider the oneline diagram shown in Figure 3.40. The three-phase transformer bank is made up of three identical single-phase transformers, each specified by X1=0.24 (on the low-voltage side), negligible resistance and magnetizing current, and turns ratio =N2/N1=10. The transformer bank is delivering 100 MW at 0.8 p.f. lagging to a substation bus whose voltage is 230 kV. (a) Determine the primary current magnitude, primary voltage (line-to-line) magnitude, and the three-phase complex power supplied by the generator. Choose the line-to-neutral voltage at the bus, Va as the reference Account for the phase shift, and assume positive-sequence operation. (b) Find the phase shift between the primary and secondary voltages.
A synchronous generator has been synchronized to an infinite grid of 13.8 kV and 60 Hz. The generator prime mover C/C is such that the no-load frequency is 62.5 Hz and the power slope is 1 MW/Hz. The AVR C/C (The reactive power against the terminal voltage C/C) is such that the zero reactive power voltage is 14.6 kV, while the slope is 0.4 MVAR/kV. Calculate: (a) the kVA loading of the generator and its power factor. (b) the settings of the prime mover and AVR such that the generator delivers 3 MW at 0.85 lagging power factor.
The reactance of a generator is given as 0.25 per-unit based on the generator’s of 18 kV, 500 MVA. Find its per-unit reactance on a base of 20 kV, 100 MVA. a. 0.0505 b. 0.0605 c. 0.0405 d. 0.0606
3 X 0.1 1 2 XL = 0.2 to Eato oto O X = 0.1 X = 0.1 Above is the one-line diagram of a simple power system. Each generator is represented by an emf behind the subtransient reactance. All impedances are expressed in per unit on a common base. All resistances and shunt capacitance are neglected. The generators are operating on no load at their rated voltage with their emfs in phase. A symmetrical fault occurs at bus 1 through a fault impedance Z, =j0.08 per unit. a) Using Thevenin's Theorem, determine the impedance to the point of fault and the fault current in per unit. (2 Marks) b) Find the bus voltages and line currents during the fault. (2 Marks)
A generator feeds power to an infinite bus through a double circuit transmission line. A 3 phase fault occurs at the middle point of one of the lines. The infinite bus voltage is 1 pu, the transient internal voltage of the generator is 1.1 pu and the equivalent transfer admittance during fault is 0.8 p.u. The 100 MVA generator has an inertia constant of 5mJ/MVA and it was delivering 1.0 p.u. power prior of the fault with rotor power angle of 30°. The system frequency is 50 Hz. If the initial accelerating power is X pu, the initial acceleration in elect dag / sec, and the inertia constant in MJ - sec / elect deg respectively will be
A power station consists of two synchronous generators A & B of ratings 250 MVA and 500MVA with inertia 1.6 pu and 1.0 pu respectively on their own base MVA ratings. The equivalent pu inertia constant for the system on 100 MVA common base is:- (a) 2.6 (b) 0.615 (c) 1.625 (d) 9.0
A short transmission line connects a step-up transformer on the source side with a series impedance of j0.5 ohms (referred to the primary) to a step-down transformer on the load side with a series imnedance of 50 ohms (referred to the primary). The turn ratio of the step-up transformer is 1:14 and a no-load primary voltage of 17 (line-to-line) kV. The step-down transformer has a turn ratio of 18:1 and it has a Y-connected, balanced load of 0.463 +j 0.0772 ohms connected to its secondary side. Assuming an ideal transmission line, the load voltage (line-to-neutral) would be: y50 O A. 14.2 kV O B. 6.52 kV O C. 17.2 kV O D. 5.07 kV O E. None of the other choices are correct
A synchronous generator is rated 645 MVA, 24 kV, 0.9 pf lagging. It has a synchronous reactance 1.2 . The generator is feeding full load at 0.9 pf lagging at rated voltage. Calculate: (a) Excitation emf (E,) and power angle 8 (b) Reactive power drawn by the load Carry out calculations in pu form and convert the result to actual values.
A short transmission line connects a step-up transformer on the source side with a series impedance of j0.5 ohms (referred to the primary) to a step-down transformer on the load side with a series impedance of 50 ohms (referred to the primary). The turn ratio of the step-up transformer is 1:10 and a no-load primary voltage of 23 (line-to-line) kV. The step-down transformer has a turn ratio of 35:2 and it has a Y-connected, balanced load of 0.490 +j 0.0816 ohms connected to its secondary side. Assuming an ideal transmission line, compute the load voltage (line-to-neutral).
A short transmission line connects a step-up transformer on the source side with a series impedance of j0.5 ohms (referred to the primary) to a step-down transformer on the load side with a series impedance of 50 ohms (referred to the primary). The turn ratio of the step-up transformer is 1:10 and a no-load primary voltage of 23 (line-to-line) kV. The step-down transformer has a turn ratio of 35:2 and it has a Y-connected, balanced load of 0.490 +j 0.0816 ohms connected to its secondary side. A capacitor bank of -j0.171 ohms is added parallel to the load. Assuming an ideal transmission line, the load voltage (line-to-neutral) would be: O A. 7360 V O B. 6.2 kV O C. 12750 V O D. 4806 V O E. None of the other choices are correct
A 30 MVA, 11 kV generator has a reactance of 0.10p.u.on its own base. Determine the per-unit reactance when referred to base kVA of 50,000 kVA and base kV of 33 kV.