Partial Discharge Pulse Segmentation Approach of Converter Transformers Based on Higher Order Cumulant

As one of the most effective methods to detect the partial discharge (PD) of transformers, high frequency PD detection has been widely used. However, this method also has a bottleneck problem; the biggest problem is the mixed pulse interference under the fixed length sampling. Therefore, this paper focuses on the study of a new pulse segmentation technology, which can separate the partial discharge pulse from the sampling signal containing impulse noise so as to suppress the interference of pulse noise. Based on the characteristics of the high-order-cumulant variation at the rising edge of the pulse signal, a method for judging the starting and ending time of the pulse based on the high-order-cumulant is designed, which can accurately extract the partial discharge pulse from the original data. Simulation results show that the location accuracy of the proposed method can reach 94.67% without stationary noise. The field test shows that the extraction rate of the PD analog signal can reach 79% after applying the segmentation method, which has a great improvement compared with a very low location accuracy rate of 1.65% before using the proposed method.

Flow control in cavity by means of sDBD actuator

This paper presents results of controlling the hydrodynamic cavity pulsations by plasma sDBD actuators. The study was held at flow velocity 36 m/s. The discharge was organized near the upstream edge of cavity. The discharge pulse energy was 0.03 J, Excitation of resonant modes, whose frequency coincides with the modulation frequency of the discharge, is obtained. Also, in the case of the detuned discharge operation, locking of the cavity to the discharge modulation frequency occurs.