The one-line diagram of a simple power system is shown in Figure 9.20. Each generator is represented by an emf behind the transient reactance. All impedances are expressed in per unit on a common MVA base. All resis- tances and shunt capacitances are neglected. The generators are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 1 through a fault impedance of Zf = j0.08 per unit. (a) Using Thévenin's theorem obtain the impedance to the point of fault and the fault current in per unit. (b) Determine the bus voltages and line currents during fault. 3 Xt = 0.1 1 2 %3D XL = 0.2 Xa = 0.1 X = 0.1
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.
The one-line diagram of a simple power system is shown in Figure 9.20. Each generator is represented by an an emf behind the transient reactance. All impedances are expressed in per unit on a common MVA base. All resistance and shunt capacitances are neglected. The generation are operating on no load at their rated voltage with their emfs in phase. A three-phase fault occurs at bus 1 through a fault impedance of Z_f = j0.08 per unit. Using Thevenin's theorem obtain the impedance to the point of fault and the fault current in per unit. Determine the bus voltages and line currents during fault.
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