Solar harvesting, as the most mature environmental energy harvesting technology, can provide a convenient, low-carbon, and off-grid solution for energy-constrained WSN in remote environmental monitoring. However, the stochastic and intermittent nature of solar energy seriously affects network energy efficiency. In this paper, we jointly consider solar harvest deployment and scheduling for clustered WSN collaborating with SWIPT, where the solar-powered cluster (SC) coordinates SWIPT to periodically broadcast energy to a set of wireless charging nodes in full-duplex mode, each member node exhausts the recharged energy for data sensing and forwarding. To maximize network energy efficiency, we formulate a Solar harvesting collaborative SWIPT Energy Scheduling(SS-CoES) optimization problem, which jointly optimizes the deployment of SCs, the energy broadcast power with time allocation, and data sensing size under the constraint of the self-sustaining demand for network energy. Given the combinational nature of the energy deployment with its strong coupling with energy scheduling, we propose a multi-layer iteration decoupling optimization algorithm based on the Dinkelbach method, which decouples the problem into three subproblems and proposes the Hybrid discrete Firefly algorithm, Lagrangian dual subgradient algorithm, and bisection search method to obtain near-optimal feasible solutions. Simulation results show that the proposed SS-CoES can effectively maximize network energy efficiency and eliminate the dependence on the grid and move chargers, achieving rechargeable wireless sensor networks (RWSN) energy self-sustainability in remote areas.

The atmospheric absorption effect greatly increases the transmission loss of terahertz (THz) waves, which limits the transmission distance. In this article, with the support of sufficient antenna gain, a series of high-frequency THz transmission windows in the ground-satellite link are presented. First, the more ideal ground-based site is determined. Based on the path loss model and the layered transmission theory, the total path loss is obtained. Combined with signal transmit power, antenna gain, signal-to-noise ratio, and noise power, total usable bandwidths and transmission windows in the 0.2–15 THz corresponding to antenna gain from 0 to 100 dBi are given. By taking the high-altitude platform as a relay link, the usable transmission windows are also given. The first six transmission windows are identified as [0.4776–0.48645 THz], [0.4906–0.49975 THz], [0.6618–0.6811 THz], [12.1015–12.10355 THz], [12.10425–12.11285 THz], and [12.11505–12.14355 THz] bands against 100 dBi gain near 1 and 10 THz bands, respectively. Furthermore, the influence of ice clouds on the transmission characteristics is analyzed. The additional attenuation in the partial usable atmospheric window frequency range can reach 1.84 dB typical, which is directly related to the effective radius and shape of particles.

An efficient analytical model based on electromagnetic (EM) topology has been developed for predicting the EM field coupling with a lossless penetrated transmission line (TL) of which the termination loads are located in two enclosures, respectively, excited by an internal vertical monopole and an external plane wave of oblique incidence. Firstly, the electric fields generated by the plane wave are calculated based on Bethe's aperture coupling theory and scalar wave function method. Then, the topology network of the EM interaction is established according to the analysis of the interference paths and the coupling mechanism from sources to the TL. Finally, the electric current induced at the line terminations is obtained by combining the generalised Baum–Liu–Tesche equation and the Agrawal's model. The analytical model has been successfully verified by the finite difference time domain method over a broad frequency range, and costs less time and fewer computational resources than numerical methods, which provides guidance for the field‐to‐line coupling in complex multiple enclosures against different sources.

High-frequency power transformers are conducive to the reliable grid connection of distributed energy sources. Polyimide is often used for the coating insulation of high-frequency power transformers. However, creeping discharge will cause insulation failure, therefore, it is necessary to use disiloxane for the purpose of modifying the molecular structure of polyimide. This paper not only introduces 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane (GAPD) with a molar content of 1%, 2%, and 5% to polyimide, but also tests both the physical and chemical properties of the modified film and the high frequency creeping dielectric strength. The results show that after adding GAPD, the overall functional groups of the material do not change, at the same time the transfer complexation of intermolecular charge and the absorption of ultraviolet light increase. There is no phase separation of the material and the structure is more regular and ordered, moreover the crystallinity increases. The overall dielectric constant and the dielectric loss tangent value show different trends, which means that the former value increases, while the latter value decreases. In addition, the resistivity of the surface and the volume increase, which is the same as the glass transition temperature. The mechanical properties are excellent, and the strength of bulk breakdown is mounting. The insulation strength of the high frequency creeping surface has been improved, which will increase with larger contents of GAPD. Among them, the relative change of the creeping flashover voltage is not obvious, and the creeping discharge life of G5 is 4.77 times that of G0. Further analysis shows that the silicon-oxygen chain links of the modified film forms a uniformly dispersed Si-O-Si network in the matrix through chemical bonds and charge transfer complexation. Once the outer matrix is destroyed, it will produce dispersed flocculent inorganic particles which have the role of protecting the inner material and improving the performance of the material. Combined with the ultraviolet light energy absorption, the increase of deep traps, the reduction of dielectric loss, and the improvement of thermodynamic performance, can better improve the high-frequency creeping insulation strength of polyimide film and its potential application value.

With increasing penetration of distributed generators (DG), the uncertainty and intermittence of renewable energy has brought new challenges to the economic dispatch and promotion of environment sustainability of microgrids. Active loads, especially in electric vehicles (EVs), are thought to be an efficient way to deal with the uncertainty and intermittence of renewable energy. One of the most important features of EVs is that their demand will vary in response to the electricity price. How to determine the real-time charging price to guide the orderly charging of EVs and operate with an uncertain renewable energy output represents an important topic for the microgrid operator (MGO). To this end, this paper formulates the optimal pricing and robust dispatch problem of the MGO as a Stackelberg game, in which the upper level minimizes the MGO’s cost, while the lower level minimizes the charging cost of each EV. In the problem, the approximate linear relationship between the node voltage and equivalent load is modeled, and the approximate linear expression of the node voltage security constraint is derived. Using dual optimization theory, the robust optimal dispatch model is transformed into a linear programming model without uncertain variables. Then, the Stackelberg game model is transformed into a mixed integer linear program by using the duality theorem of linear programming. Finally, the effectiveness of the proposed method is proved by simulation within the modified IEEE33-bus system.

An efficient field‐to‐line coupling model in the time domain is developed combining the second‐order decoupled multiconductor transmission lines (MTLs) equations and the finite‐element time‐domain (FETD) method for evaluating the electromagnetic (EM) transient response of MTLs over a lossy ground excited by a high‐altitude EM pulse (HEMP). First, the incident HEMP electric fields on the lines are calculated as equivalent distributed sources introduced into the MTLs equations. Then, the discrete FETD equations for the lines against the HEMP, in which the effect of frequency‐dependent parameters caused by the ground impedance is considered, are derived using the FETD method with current as the single iteration variable. Finally, the transient currents induced on the lines are obtained by assembling all the discrete FETD equations into the global FETD equation, and the transient induced voltages on the lines are calculated by discretising the coupled equations with respect to current and voltage. The proposed model is successfully compared with the finite‐difference time‐domain method via several examples. It is then employed to analyse the effect of various parameters on the transient currents including the polarisation and the incident angles of the HEMP, the conductivity, and the relative permittivity of the soil.