Research On Voltage Sag Source Identification And Source Location

Modern industrial equipment tends to be integrated and sophisticated,especially high-tech industrial equipment with digital and information technology as the core,which is very sensitive to changes in power supply voltage.The contradiction between the unavoidable voltage sag event of the power system and the increasingly sensitive electrical equipment is becoming more and more prominent.For the electrical side,the use of appropriate control devices can effectively alleviate the impact of the voltage sag on sensitive equipment;For the power grid,it is of great practical significance to establish a reliable and sensitive voltage sag source identification and source location system.This article relies on the China Electric Power Research Institute(Nanjing Branch)to carry out research on the user-side voltage sag treatment equipment,and then focuses on the source identification and source location of the voltage sag.This thesis first elaborates the background and research significance of the subject,and studies the current research status of the source identification and source location of voltage sags at home and abroad.The concept of voltage sag,the classification of the cause of voltage sag,the hazards of voltage sag,and the mitigation measures of voltage sag are studied from the power grid side,the equipment side,and the user side.Afterwards,the research focused on the source identification and source location of voltage sag.In terms of voltage sag source identification,a new type of voltage sag source identification method is used to build a one-dimensional convolutional neural network and compare loss functions to study the voltage sag type identification technology that requires only a small amount of labeled real data.This method only uses the real power grid voltage recording waveform,and introduces the few sample learning technology based on the twin network to pre-train the model first,and finally can realize the effective identification of the sag source type.It is verified by the actual measurement data of the power grid provided by the internship unit,which shows the effectiveness and accuracy of the method for source identification and judgment.In terms of voltage sag source location,the wavelet energy entropy is applied to the voltage sag source location method.This method takes the voltage amplitude change at the monitoring point at the time of the fault as the measurement quantity,and the magnitude of the change is quantified by the wavelet energy entropy.At the same time,it can filter the interference noise generated by the transient disturbance signal in the power system,further improve the simulation result,and finally realize the positioning estimation of the relative position of the sag source and the monitoring device.The IEEE-14 node standard test system was used for simulation and verified by the actual measurement data of the power grid provided by the intern unit.The results showed that the method is practical for the judgment of sag source location.