A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and mechanical power input are adjusted to give E = 24 kV and power angle δ = 30 degree. a) Determine the line current and active and reactive power fed to the generator terminal. b) The mechanical power input to the generator is increased by 20% from that in part (a) but its excitation is not changed. Find the new line current and power factor. c) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δ and mechanical power input. d) With the reduced current as in part (c), the power is to be delivered to generator terminal at unity power factor, what are the corresponding values of E and δ and also the mechanical power input to the generator. Per-unit values are given on machine rating as the base.
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.
A three-phase, 250 MVA, 16 kV rated synchronous generator is feeding into an infinite bus bar at 15 kV. The generator has a synchronous reactance of 1.62 pu. It is found that the machine excitation and
a) Determine the line current and active and reactive power fed to the generator terminal.
b) The mechanical power input to the generator is increased by 20% from that in part (a) but its excitation is not changed. Find the new line current and power factor.
c) With reference to part (a) current is to be reduced by 20% at the same power factor by adjusting mechanical power input to the generator and its excitation. Determine E, angle δ and mechanical power input.
d) With the reduced current as in part (c), the power is to be delivered to generator terminal at unity power factor, what are the corresponding values of E and δ and also the mechanical power input to the generator.
Per-unit values are given on machine rating as the base.
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