Simulation of three-phase short-circuit at the terminals of synchronous machine
Three-phase sudden short-circuit at the terminals of a synchronous machine under open circuit condition is simulated. The standard parameters are calculated by using the known parameters, and substituted into the analytical expression for computing short-circuit current. The curve of the relationship between the maximal armature momentary current and the rotor angle is plot. It is concluded that the armature momentary current is maximal when short-circuit occurring at the time of the terminal voltage wave is going through zero. Furthermore, a simulation model in SIMULINK environment is constructed, thus the oscillograms of the armature short-circuit currents in the three phases and the field short-circuit current are plot.
Performance of Superconducting Synchronous Generator for Three-Phase Short-Circuit at Its Terminals
In this paper, three-phase short-circuit at the terminals of a superconducting synchronous generator is simulated by using MATLAB. In this simulation, a single screened superconducting generator directly connected to power system is considered and two operating cases are investigated: the first case is that the fault is permanent and the second case is that the fault is cleaned by a protection system. To show the effects of this short-circuit and the performance of the superconducting synchronous generator for both cases, the deviations of armature momentary currents, angular speed and field current are plotted. In order to compare the obtained results, the present simulations for the both cases mentioned above are repeated for a conventional synchronous generator having the same rating as considered superconducting counterpart, which is directly connected to power system, and the deviations of the same variables as considered for the superconducting synchronous generator are also given in the paper.
Generator Models Established by Frequency Response Tests on a 555 MVA Machine
An accurate model of a turbogenerator is required for excitation and transient stability studies. Frequency response tests have been made on a 555 MVA unit to determine direct and quadrature axis transfer functions under operating conditions. Digital and analog computations were performed on line in the course of system tests. The performance of the model derived from the test results compares satisfactorily with the behaviour observed in service.