The Power Quality Disturbance Detection Method Research Based On Phase Space Reconstruction

In recent years, with the development of science and the expansion of industrial scale, the new technology, new process widely used in every aspect of people’s life and industrial production, power users requirement for power quality are also gradually improve. At the same time, application of a large number of non-linear devices to the power network injection various electromagnetic interference, the normal work of electrical equipment and the economic operation of power system has brought great influence and harm, the problem of the power quality is increasingly serious, caused widespread concern of the electric power enterprises and users. Improve the power quality is of great significance for the security and stability of power system. Voltage notch is a periodic voltage disturbance phenomenon appeared in power grids caused by electrostatic discharging and power electronic device commutation, with the widespread use of power electronic devices, voltage notch phenomenon occurs more frequently, the adverse effects arouse people’s attention gradually. Voltage notch was formally listed as the content of the voltage disturbance. Therefore, to explore a simple and effective method of voltage notch detection and parameter identification is necessary. In addition, with the increasingly complex of power system structure and increasing non-linear devices, disturbances in power system, most of the complex disturbance, accurate detection of complex disturbance of power quality governance is of great importance. Based on this, detection of the voltage notch and parameters identification and detection of complex disturbances are analyzed and studied in this paper.First of all, to determine the phase space reconstruction parameters, the attractor is reconstructed using coordinate delay method, and the optimal delay is determined with mutual information function, sequence of correlation dimension is calculated to determine the optimal embedding dimension. The voltage notch detection and parameter identification algorithm is put forward, to ensure that the voltage notch can be effectively detected during the voltage sags and swells. On the basis of embedded signal phase track after reconstructing phase space to detect the occurrance of voltage notch and extract the angle and width of the notch. Defined RMS depth and maximum depth of voltage notch, by constructing a sine function combined with phase points component, the depth of the notch can be abtained.Secondly, according to the characteristics of the complex disturbance signal and combining with the phase space reconstruction technology to design the detection and localization algorithm of complex disturbance signal. The disturbance signals and fundamental component reconstruct phase space respectively and subtract to get the trajectory of graphics, normal part of the disturbance signals is lose, the trajectory of graphics represents complex disturbance, the changes in regional of disturbance signal can be clearly detected through the trajectory of graphics, based on this to detect and locate complex disturbance.Finally, under the environment of Matlab simulation, mathematical models were constructed of voltage notch and complex disturbance signal, simulation was carried out of the above two parts. The examples analysis show that the presented method is competent to fufil the voltage notch detection and characteristic parameters identification tasks, complex disturbance signal can be accurately detected and located.