Research on the accurate fault location of AC substations based on switching action logic

Abstract

Abstract AC substation systems contain multiple devices and components, which affect each other, resulting in increased system complexity and difficulty in locating power faults. However, the complexity of the system increases the difficulty of analysis and judgment, and puts forward higher requirements for the accuracy of algorithms and logic. Therefore, an accurate fault location method for AC substations based on switching action logic is proposed. Taking the YnD11 connection mode as an example, the operation model of the phase selection switch of the isolation switch is constructed, and the operation logic of the phase selection switch of the isolation switch is obtained. The phase amplitude and phase relationship of the three-phase isolation switch are analysed, and the appropriate switching strategy is selected to reduce the influence of electromagnetic coupling. Based on this, the time-frequency and frequency-domain information of the power signal is obtained by the wavelet decomposition method, and the local characteristic value of voltage signal is quantified. The fault location of the filtered the voltage signal is completed by the wavelet transform mode maximum method. The experimental results show that the no-load current has good linearity and almost no harmonics, and the results of the disturbance location are closer to the actual situation.