Fast Current Detection Method Based On Multi-Resolution Wavelet Coefficient Fusion Guided By Modulus Maxima Principle

With the high proportion of distributed generation connected to the power grid, the first half wave current limiter, as the key equipment to suppress the surge of short-circuit current, puts forward higher requirements for the rapidity and reliability of its matching current detection methods. In order to enable the first half wave current limiter on the bus to be put into operation quickly in the early stage of fault, a fast current detection method based on multi-resolution wavelet coefficient fusion guided by modulus maximum principle is proposed in this paper. In this method, the current data in a fixed time window is used as the fault detection quantity for multi-resolution decomposition, and the high-frequency coefficient reflecting the change of signal details is obtained. The three-scale detail coefficient is used to sum the absolute value to construct a new criterion, which realizes the rapid detection of current under most faults and any initial phase angle. Considering the rapidity and accuracy under various working conditions and interference signals, the performance indexes of this method and common current detection methods are compared. The simulation results show that the method has good performance, strong robustness, and can quickly and accurately identify line faults.