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A novel method to make a round end rectangular joint whose total length is much larger than the diameter of the laser spot, named as incremental laser shock clinching, was proposed in this paper. Experimental and numerical investigation was conducted to verify the feasibility for joining three sheets of copper/aluminum/stainless steel. The transverse section and the appearance of the joint were explored to determine the spacer height and the forming strategy. The shape evolution of interlock was discussed by observing sectional images. To describe the material flow characteristics in the forming process, a series of typical points were traced. The mechanical properties of the joints relating to the load directions and clamping ways were studied by tensile shear tests. The results show that fine joints with smooth surface morphology and uniform thickness can be obtained under the larger spacer height and multi-pass forming strategy. Simulated results agree well with the experimental results, which implies that the finite element model can be effectively used to analyze the process. During deformation, most material flows along the transverse direction to form undercuts, meanwhile flows slightly towards the laser spot moving direction. What’s more, the maximum load in the perpendicular shear test is larger than that in the parallel shear test. Two failure modes are observed when the copper foil and pre-slotted sheet are clamped on one side and only one failure mode is found when the copper foil is clamped alone.

Nonvolatile processor (NVP) attracts more and more attentions for its immunity to power loss in energy harvesting scenarios. The overall performance of an NVP is determined by its sleep and wake-up speeds, which refer to how fast the NVP can turn itself off and on when a sudden power failure occurs. To the best of our knowledge, this paper is the first work to improve the system-level sleep/wake-up speed of an energy harvesting NVP. A hybrid CMOS/ferroelectric nonvolatile flip-flop (nvFF) and a high-speed voltage detector are designed and integrated in the proposed NVP to jointly minimize its sleep and wake-up time. Measurement results demonstrate $46~\mu \text {s}$ wake-up time and $14~\mu \text {s}$ sleep time, which is up to 18 and 24 times speedup over existing works. This approach not only improves the robustness of the NVP to power fluctuations but also brings significant advantages for better utilization of harvested energy.

The interconnected power grid emerges because of the temporal and spatial difference of power generation and power utilization as well as the precondition of considering the complementary resources, safety and reliability. The economic dispatch of multi-area interconnected power grids can realize the effect in scale economies and mutual complementary cooperation in supporting capacities of frequency and voltage, to achieve a wider range of the optimal allocation of resources. Considering the increasing power grid interconnection in the new situation and the trend of resource allocation in the wide range, this paper proposes the economic dispatch method for interconnected power grid considering transmission flexibility. The bus tearing method is applied to split the interconnected power grid, and the decomposition-coordination model is built based on the alternating direction multiplier method. In addition, the alternating direction multiplier idea is introduced to realize the parallel computation of the economic dispatch of each regional power grid. The calculation results of each area are coordinated by the central coordination unit, and the iterative calculation is carried out alternately until the convergence solution is obtained. Numerical example analysis illustrates the effectiveness and economic benefits of the proposed dispatch method.

As a by-product of nickel production, the ferronickel slag (FNS) puts a lot of pressure on the environment. It is becoming more and more urgent to deal with the increasing FNS. The aim of this study is to explore the durability of concrete with FNS fine aggregate. Two kinds of FNS with different storage time were selected. The radioactivity detection, XRD test and stability detection of FNS were conducted to ensure FNS can be used as construction materials. Then the durability of concrete with 13%, 27%, 40% and 50% FNS (by weight of fine aggregate) was investigated, respectively. It was found that the properties of concrete prepared from FNS with different storage time had little difference. The results indicated that 27% FNS replacement showed improvement in resistance to sulfate attack by 22% but the resistance to chloride ion penetration was not significantly influenced. Moreover, 40% FNS addition brought a 33% abrasion reduction than that of original concrete. SEM analysis showed that FNS produced more C-S-H gels and improved the microstructure of concrete. This study indicated that proper content of FNS can be used as fine aggregate and it was beneficial to the durability of concrete, especially to the abrasion resistance.

With the increasing penetration of distribution generations, distribution system is characterized by complex injection uncertainties, which brings formidable challenges for distribution network operation. As distributed renewable energy penetrating into power network, the operation mechanism and control strategy of distribution network become more complex, which makes it necessary to adjust the control measures to improve the operation quality and efficiency. In order to deal with the increasing uncertainties caused by renewable generations, a voltage aware synergetic dispatch method of active distribution network is proposed. By accounting for the voltage regulation characteristics of all kinds of generators and loads, flexible network topology and participation mechanism of regulation reserves of synchronous generators and connected transmission network in response to uncertainties, an optimization model of voltage aware synergetic dispatch of active distribution network is constructed. The proposed model is formulated as a mixed-integer nonlinear optimization problem and is resolved by the combination of firefly algorithm and nonlinear primal-dual interior-point method. Finally, case studies on the modified IEEE 33-bus distribution system are conducted to illustrate the effectiveness of the proposed method.

In order to deal with diversity of massive data structures and the variety of information formats, a novel mechanism is designed for unified management of power grid planning data. By integrating many business systems including production management system (PMS), geographic information system (GIS), energy management system (EMS), distribution network information acquisition system in the power supply company's system and adopting various technical means such as data warehouse technology (e.g. ETL, Extract-Transform-Load) and incremental capture, data structure that supports the whole process management of power grid business is designed, data correlation analysis and integration & migration are carried out, and efficient access and deep fusion of massive relational data, file-type data, distributed data and spatial data are realized. Besides, through computing modes such as diagnostic analysis, load analysis and spatial analysis, the integrated database for power grid planning that integrates data fusion, storage, mining, modeling, computing, analysis and intelligent perception is finally constructed based on the designed data management mechanism, which could provide the comprehensive model and data support for power grid development. Field application shows the engineering benefit of the designed data management mechanism.

To deal with the increasing penetration of uncertainties caused by renewable generations and uncertain loads, this paper proposes a novel robust optimization model for the optimal power flow (OPF) problem of power systems. In the model proposed, the generation and the network topology are co-optimized, and then the proposed robust optimal power flow with transmission switching (ROPF_TS) model is converted to be a two-stage mixed-integer optimization model based on the duality theory. Based on Benders decomposition, the model is decomposed into a master problem and a slave problem, the master problem corresponds to the resolution of the deterministic optimal power flow with transmission switching problem under base-point mode, the slave problem corresponds to the robust optimal power flow with the given network topology, and then the feasible domain of the master problem is restrained by the Benders cuts developed by the slave problem. Finally, Example analyses are conducted to verify the validity of the proposed model and its solution methodology.

Based on the integration of power production management system, electricity information management system, supervisory control and data acquisition, the power grid planning platform support the power planning by big data technology. Load forecasting and analysis play an important role in power planning. By collecting real-time load data and putting history load data into database, power grid planners can implement load data calculation and analysis in different time scales. Load forecasting reveals the multidimensional and multilevel feature. By exploiting multi-level load forecasting system based on power grid planning platform, “point-line-plane-solid” fore-level coordinated load forecasting can be realized. With the popularization and application to provincial company and citywide companies, the punctuality and accuracy of this system has been proved.

Different power grid operation mode corresponds with different short-circuit capacity distribution, while different distribution of short-circuit (current) capacity is contradictory to power grid operation performance and equipment tolerance influence consequence. This paper establishes functional relationship between short circuit (current) capacity of power grid and effective switch set and feasible power grid operation mode on this basis, deploys analysis on relationship between short circuit (current) capacity of power grid and feasible power grid operation mode on the basis that an equivalent topology analysis model is built, in order to take equipment tolerance into consideration in a compromised way during making of decisions concerning with power grid operation mode and extend power grid operation scheduling.

By analyzing the various factors affecting the current carrying capacity of power cable in actual operating environment, the mathematical model of temperature change of cable in the actual operation can be obtained. On this basis, establishing a dynamic relationship between its real-time current carrying capacity and operating temperature, and solving by algebraic equations and differential equation alternately, to study the dynamic changing process between its current carrying capacity and operating temperature of cable in real-time operating conditions. Finally, the example proves that the study of current carrying capacity of cable in real-time operating environment can be as far as possible to play its maximum transmission capacity and improve operating efficiency.