Time Domain Hilbert Transform Method

Signal detection, extraction and analysis means a lot to theoretical research and engineering practice in power system. Both the operation and control of system under steady state conditions, and relay protection and system detection under electromagnetic transient condition can provide many useful data. The dynamic characteristics all needed to be caught quickly and accurately. The traditional signal processing methods mainly focuses on frequency signal of the system, while neglect to extract and the analysis characteristics of non-stationary components under fault conditions of the system. In fact, the transient characteristics of power system contain a wealth of valuable information, though it will be more difficult to extract and process as the complexity of the signal increases significantly. So to come up with a new method to help analyze these kinds of signals is of great value to theoretical research and engineering applications.This article introduces the frequently used signal processing method in power system. After describing the development and theoretical basis of time domain analysis, frequency domain analysis, time-frequency analysis and other aspects, then talk about each analyze methods' advantages and disadvantages and application in use. Aiming at the lack of research on non-stationary signals, a new method based on sinusoidal transform method and characters of Hilbert transform is proposed. This method can use advanced least square method to deal with sampling signals, and then come up with a pair of primary functions, called time domain Hilbert transform method.The new time domain Hilbert transform method can tell the inner properties of Hilbert method on a new perspective, this help people have a better understanding of instantaneous characters. And also makes it more accurate to do the calculation and makes up the influence of impulse response and data truncation. This new method can avoid signal distortion while directly give the Hilbert transform expression within the limited time period. Based on the establishment of a strict mathematical theory, the new method carries out some detailed characters and gives the digital calculation method that can be used in reality.Finally, this thesis verifies the accuracy and practicability of the time domain Hilbert transfer method on the base of Matlab software by simulating the typical signals of power system. Meanwhile, this method is used to make comparison with several classical signal processing methods to fully demonstrate the generalized sinusoidal signal processing method of transient power signal's advantages on Hilbert transform.