The negative sequence current of a solidly grounded generator for single line to ground fault is j 2.5 p.u. Then the current flow through the neutral during the fault is
Q: Line to ground fault has the highest probability in the power system O True False
A: Need to find true false
Q: If a generator double-line-to-line fault occurs across "b" and "c" to ground, and Ea = 235 VZ0°, Z,…
A: In this question we need to find a sequence current , fault current and sequence voltage.
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A: 6.6 kV and 12 MVA x1=0.15x2=0.75x3=0.30
Q: The zero sequence current of a generator for line to ground faults is į 3.0 p.u. Then the current…
A: Given, For the line to ground fault, the zero-sequence current, I0=j3.0 pu
Q: Which among the following faults does mostly happen in 3-phase power systems? Single line to ground…
A: As 3 phase fault in power system are, 1. Single Line to Ground fault 2. Three phase short circuit 3.…
Q: A 70-kV, three-phase short .Determine t
A: It is given that: V= 70 kVL=18 KmZphase=1+j5 ΩPR3-ϕ=90 MW
Q: Single line to ground fault is one type of the symmetrical fault. Select one: O True O False
A:
Q: For the system shown in Fige, a 3-phasefault Loccurs at the beginning ofT.L. Determine 1.…
A: “Since you have posted a question with multiple sub-parts, we will solve first three sub parts for…
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Q: Generators generate positive sequence voltage only False True
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Q: QIS) For a power system: Line to line fault current =-j 2.5 p.u. 3-0 fault current =- j 5 p.u. The…
A: Given: Line to line fault current is -j2.5 p.u. And three phase fault current is -j5 p.u.
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Q: Problem2 A generator having H = 6.0 MJ /MVA is delivering power of 1 per unit to an infinite bus…
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Q: It is required to put resistance in neutral of alternator to control the fault current to rated line…
A: Given data, Positive sequency reactance = 0.3 pu Negative sequence reactance = 0.4 pu Zero sequence…
Q: 2. Explain how the value of fault current can be computed for L-L-G fault occurring at the unloaded…
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Q: the slip-rings replaced by separated segments In order to generate a bidirectional Voltage true /…
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A: In a LLLG symmetrical fault the fault currents are equal.
Q: It is required to keep L-G fault current with zero fault impedance to rated line current. Determine…
A: In this question we need to find a reactance need to be placed in neutral of genrator to limit the…
Q: It is required to keep L-G fault current with zero fault impedance to rated line current. Determine…
A: Given:Z1=0.35p.uZ2=0.5p.uZ0=0.05p.uWe need to find the value of reactance that need to be placed in…
Q: An unloaded star connected solidly grounded 10 MVA, 11 KV generator has positive, negative and zero…
A:
Q: three phase generator with constant terminal voltages gives the following currents when under fault:…
A: The solution can be achieved as follows.
Q: In a short circuit test on 132 kV, 3-phase system, the breaker gives the following results: Power…
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Q: V, =1.025Z0°pu P=300MW j0.05 Bus 1 Bus 3 V = 1.03 Slack j0.025 j0.025 Bus 2 400MW 200MVAR
A: The given power system can be redrawn as shown below:
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Q: A 15 MVA, 11 kV, alternator has positive, negative and zero sequence reactance are 0.3 p.u., 0.2…
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Q: Due to the fault in all the phases at bus -5 the positive sequence fault current of -j1.125 flows to…
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Q: The zero sequence currents of a generator for line to ground fault is j2.4 p.u. then the current…
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Q: A 30kV, 50MVA generator having a solidly grounded neutral and Z1 = 0.25pu, Z2=0.15pu and Z0=0.05pu.…
A: Part (a) Given values are 30KV,50MVA, Z1 = 0.25pu, Z2=0.15pu and Z0=0.05pu. For single to ground for…
Q: A three-phase synchronous generator produces 10 MVA power under a rated voltage of 10 kV. Zero…
A: Hello. Since your question has multiple sub-parts, we will solve the first three sub-parts for you.…
Q: Single line to ground fault of a solidly grounded generator positive sequence current is j2.5 p.u,…
A: For any current in the neutral = 3×zero sequence current. For single line to ground fault zero…
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Q: Q7: Generators G and G2 are identical and rated 11 kV, 20 MVA and have a transient reactance of 0.25…
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A: Given, Zbus=j1j1j1j1j2.55j1.67j1j1.67j3the pre-fault voltages are,V1=V2=V3=2 p.u.the bus-2 is a…
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A: A three-phase fault occurs at 75% of the distance from bus G as shown in figure The fault has 10 arc…
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A: For double-line to ground fault, Vb=Vc=0Ia=0 Let the fault phases are b and c, then The positive,…
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- For large power transformers rated more than 500 kVA, the winding resistances, which are small compared with the leakage reactances, can often be neglected. (a) True (b) FalseThree single-phase two-winding transformers, each rated 25MVA,34.5/13.8kV, are connected to form a three-phase bank. Balanced positive-suence voltages are applied to the high-voltage terminals, and a balanced, resistive Y load connected to the low-voltage terminals absorbs 75 MW at 13.8 kV. If one of the single-phase transformers is removed (resulting in an open connection) and the balanced load is simultaneously reduced to 43.3 MW (57.7 of the original value), determine (a) the load voltages Va,Vb, and Vc; (b) load currents Ia,Ib, and Ic; and (c) the MVA supplied by each of the remaining two transformers. Are balanced voltages still applied to the load? Is the open transformer overloaded?Figure 3.39 shows a oneline diagram of a system in which the three-phase generator is rated 300 MVA, 20 kV with a subtransient reactance of 0.2 per unit and with its neutral grounded through a 0.4- reactor. The transmission line is 64km long with a cries reactance of 0.5-/km. The three-phase transformer T1 is rated 350MVA.230/20kV with a leakage reactance of 0.1 per unit. Transformer T2 is composed of three single-phase transformers, each rated 100 MVA, 127/13.2kV with a leakage reactance of 0.1 per unit. Two 13.2kV motors M1 and M2 with a subtransient reactance of 0.2 per unit for each motor represent the load. M1 has a rated input of 200 MVA with its neutral grounded through a 0.4- current-limiting reactor, M2 has a rated input of 100 MVA with its neutral not connected to ground. Neglect phase shifts associated with the transformers. Choose the generator rating as base in the generator circuit and draw the positive-sequence reactance diagram showing all reactances in per unit.
- Two alternators rated 30 MVA and 20 MVA have per unit reactance of 0.30 and 0.50 respectively are connected to a common 12-kV bus bar. Solve the fault current if a symmetrical 3-phase fault occurs at the bus bar.2. The positive, negative and zero sequence reactances of a 20MVA, 13.2 kV synchronous generator are 0.3 pu, 0.2 pu and0.1 pu respectively. The generator is solidly grounded andis not loaded. A line to ground fault occurs on phase a.Neglect all resistances, determine the fault current.A 30kV, 50MVA generator having a solidly grounded neutral and Z1 = 0.25pu, Z2=0.15pu and Z0=0.05pu. a. Calculate the fault current and voltages for a single line to ground fault. b. Sketch the phasor diagram for the fault voltages.
- A 25 MVA, 13.2 kV alternator with solidly grounded neutral has a subtransient reactance of 0.40 p.u. The negative and zero sequence reactances are 0.20 and 0.3 p.u. respectively. Find the fault current when, (i) A single line to ground fault occurs at the terminals of an unloaded alternator and (ii) ALL fault occurs.A three-phase synchronous generator produces 10 MVA power under a rated voltage of 10 kV. Zero sequence component reactance of this generator is given as X0 = j0.1 pu, positive sequence component reactance X1 = j0.1 pu and negative sequence component reactance X2 = j0.1 pu, and the star point of this generator is given as Xn = j1 Ω grounded. a) Calculate the real value of the fault current that will occur in the three-phase short circuit fault at the output of this generator. (The actual value of the fault current will be calculated and entered AS INTENT (such as 3550. Values entered as per unit will not be accepted.) b) Calculate the real value of the fault current that will occur in the case of single phase-ground short circuit fault at the output terminal ends of this generator. (The actual value of the fault current will be calculated and INTENT (such as 3550) will be entered. Values entered as per unit will not be accepted.) c) Calculate the real value of the fault current…An unloaded star connected solidly grounded 10 MVA, 11 KV generator has positive, negative and zero sequence impedances are j 1.3 Ω,j 0.8Ω and j 0.4Ω respectively. A single line to ground fault occurs at the terminals of the generator. (i) Calculate the fault current. (ii) Determine the value of the inductive reactance that must be inserted at the generator to limit the fault current to 50% of the value obtained in (i)
- In a short circuit test on 132 kV, 3-phase system, the breaker gives the following results: Power factor of the fault = 0.45. Recovery voltage 0.9 time of full line voltage. The breaking current is symmetrical. The restriking transient has a natural frequency of 15 kHz. Calculate the rate of rise of restriking voltage (RRRV) in the following types of faults: (1) Grounded fault (2) Undergrounded fault.the slip-rings replaced by separated segments In order to generate a bidirectional Voltage true / falseA generator is rated 100 MVA, 15 kV. It is Y-connected, solid grounded and is operated at rated voltage at no-load and is disconnected from the rest of the system. Its positive and negative sequence reactances are 0.10 p.. and its zero sequence reactance is 0.05 p.. Calculate in ohms of inductive reactance to be inserted in the neutral connection of the generator to limit the fault current for a single line to ground fault to the fault current of a symmetrical three-phase fault.
