Question: A 60-Hz synchronous generator having inertia constant H~4 MJ/MVA and a direct axis transient reactance X₂-0.2 per unit is connected to an infinite bus through a purely reactive circuit as shown in following circuit. Reactance are marked on the diagram on a common system base. The generator is delivering real power P₂=0.7 per unit and Q=0.05 per unit to the infinite bus at a voltage of V=1 per unit. (a) A temporary three-phase fault occurs at the sending end of the line at point F. When the fault is cleared, both lines are intact. Determine the critical clearing angle and the critical fault clearing time. (b) A three-phase fault occurs at the middle of one of the lines, the fault is cleared, and the faulted line is isolated. Determine the critical clearing angle. XL1-0.5 XL2-0.6 V- 1 pu X'd-0.2 Xt-0.1 (c) A three-phase fault occurs at a point on one of the lines that are twice as far from one side as the other. After the fault is cleared, the faulted line is isolated. Determine the critical clearing angle.
Load flow analysis
Load flow analysis is a study or numerical calculation of the power flow of power in steady-state conditions in any electrical system. It is used to determine the flow of power (real and reactive), voltage, or current in a system under any load conditions.
Nodal Matrix
The nodal matrix or simply known as admittance matrix, generally in engineering term it is called Y Matrix or Y bus, since it involve matrices so it is also referred as a n into n order matrix that represents a power system with n number of buses. It shows the buses' nodal admittance in a power system. The Y matrix is rather sparse in actual systems with thousands of buses. In the power system the transmission cables connect each bus to only a few other buses. Also the important data that one needs for have a power flow study is the Y Matrix.
Types of Buses
A bus is a type of system of communication that transfers data between the components inside a computer or between two or more computers. With multiple hardware connections, the earlier buses were parallel electrical wires but the term "bus" is now used for any type of physical arrangement which provides the same type of logical functions similar to the parallel electrical bus. Both parallel and bit connections are used by modern buses. They can be wired either electrical parallel or daisy chain topology or are connected by hubs which are switched same as in the case of Universal Serial Bus or USB.
Hi, I was having trouble solving this practice example. I see part a and b are already solved, but i am having trouble understanding the procedure. Especially the part where the Xeq is solved for. If you could explain this as well as part c). that would be appreciated.
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