The essay describes the basic principles and the method of application of prony algorithm, as well as how to use prony algorithm to fit fault signal and extract the corresponding transient parameters. And on this basis, the order of the signal model, the data window length, sampling interval and the parameters such as attenuation factor are determined. Then, the correctness of the prony algorithm is verified by the means of extracting of the small current grounding fault transient component.

Concerned that wind generators start up and establish the stable terminal voltage of the stator which is connected to the grid, this paper presents that wind generator can be operated as the independent generator at a certain voltage and frequency by means of capacitive excitation. The paper also deduces the calculation method for the proper capacitance value of self-exciting startup of wind generator. The paper builds a simulation model based on real time digital simulator (RTDS) and takes a case for simulating self-excited startup of wind generator. Simulation results demonstrate that the wind generator with self-excitation can successfully start up and be connected to the grid, it make a good agreement of actual situation. Furthermore, the results of RTDS simulation show that only proper capacitors value from optimized calculation can lead to a normal terminal voltage characteristic. The validity of proposal methods and designed simulation model is verified by experimental and computed results.

At present the transient mechanism in lumped parameter for analyzing single-phase grounding fault in indirectly grounded power system exist deviations. This paper analyzes the amplitude-frequency and phase frequency characteristics of the impedance in line-mode network and zero-mode network through the distribution parameter model of transmission lines. This paper also analyzes the mechanism of LC resonant process. A high precision model of single-phase grounding fault in system with neutral point ungrounded is established using simulation software like ATP and Matlab, and the resonance mechanism of the single-phase grounding fault transient process in the proposed system with neutral indirectly grounding system simulated and identified.