The uncertainties caused by sources and load switchings and the equivalent negative impedance of constant power loads (CPLs) commonly exist in microgrids and often undermine the system stability and damping. A distributed secondary $H_{\infty}$ consensus approach with an event-triggered communication scheme is proposed for DC microgrids to achieve accurate current sharing and satisfactory performance in the presence of CPLs and uncertainties. The proposed event-triggered communication scheme only requires the information at every fixed sampled interval. Global large-signal stability of the DC microgrid with CPLs and uncertainties is analyzed, where a primary plug-and-play (PnP) voltage controller is considered for each distributed generator. Further, effects of key controller parameters and CPLs on the dynamic performance is analysed, and a PnP design method is presented for the primary-secondary controllers. Full PnP operation and reduced communication of the DC microgrid can be realized. Finally, simulation results are presented to validate the proposed method.

Flash sintering is a novel field‐assisted sintering technology for ceramics that allows a dramatic reduction in processing time and temperature. Since 2010, when flash sintering was first reported, it has been a focus of research interest in the field of materials science. Recent study results have confirmed that the sintering temperature decreases with the strength of the applied electric field; for some ceramics, the sintering temperature can be lowered even to room temperature. This represents an innovative breakthrough for ceramic sintering at ultra‐low temperatures. However, once the electric field strength in flash sintering is increased, new questions and challenges arise, such as whether or not partial discharge occurs in the green body if under electro‐thermal coupling stress, how to quantitatively analyse the impact of discharge on sintering, and, moreover, whether the sintering mechanism under a strong electric field is consistent with that under a weak electric field. These research questions require knowledge of partial discharge detection, dielectric theory, and other topics that are beyond the scope of materials science. To address this need, this review summarises the work carried out in flash sintering with a strong electric field from the perspective of high voltage and insulation technology. First, the flash sintering process and mechanism are briefly introduced. Then, the published literature on flash sintering with a strong electric field for various ceramic materials is summarised in depth. In addition, experimental phenomena that are observed in flash sintering with a strong electric field, such as flash and blackening, are discussed. Finally, some suggestions for future work are presented. It is anticipated that the knowledge gap between different areas of study can be filled by this review.

Distributed generators are integrated into microgrids or geographically distributed subsystems in active distribution networks and may belong to various entities. Centralized solutions cannot meet future requirements such as high resilience and privacy protection. Therefore, fully distributed economic dispatch (ED) methods are needed and most existing algorithms exhibit first-order convergence. This paper introduces an efficient fully distributed dynamic ED solution for minimizing photovoltaic (PV) power curtailment, based on a parallel primal-dual interior-point algorithm with a quasi-Newton technique. In this method, each area optimizes its own problem with limited information exchanged with its neighbors, and no central coordinator is needed. Based on a peer-to-peer communication paradigm, this method can achieve a global optimum while the privacy of each area is obliquely protected. Numerical tests demonstrated that the algorithm outperforms gradient-based methods such as ADMM and maintains stability under a partial communication failure.

After a long-term operation, defects may occur in the composite insulators and threat the safe operation of the power transmission. To secure the power transmission system, it would be beneficial to detect the defects in their initial stage. In this paper, the terahertz technique combined with a deconvolution method was proposed, and a terahertz time-domain spectroscopy system was built. To validate the method proposed, three types of defects, namely single air gap defect, inclusion defect, and double-layer air gap defect were artificially prepared and tested. According to the test results, it was found that, compared with the traditional terahertz method, the air gap size that could lead to pulse overlapping was reduced from 1.22 mm to 0.57 mm. After the deconvolution process, air gap defect as small as 0.173 mm could be distinguished due to the shape characteristics of unipolar pulse. It was also found that when the defect was damp, the obtained waveform near the defect became smooth. The results of the present study demonstrate that terahertz time-domain spectroscopy (THz-TDS), combined with the deconvolution method, can have high potential in the detection of defects in composite insulators.

Misalignment of wireless power transfer (WPT) system’s transmitting and receiving ends can cause severe efficiency degradation and electromagnetic radiation. In this paper, a novel parallel transmission (TX) coil matrix structure was proposed to improve the performance of the WPT in the misalignment condition. The receiving (RX) coil’s position measurement method was innovated by investigating the magnetic field and the mutual inductance change caused by the relative position change between RX and TX coils. Both theory and experiments confirmed that the phase difference between signal coil and detector coil can be featured as the parameter to represent the magnetic field’s change. Based on this principle, a 4×4 TX coil matrix was made which verified the proposal and the sensitivity of the sensor. It was found that the position measurement result was sufficient to decide which TX coil to gate to facilitate the wireless charging in misalignment conditions. The structure and the size of the TX coil matrix could be further optimized to enhance the sensor’s reliability and sensitivity.