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The preventive control strategy can be solved quickly and effectively through the linear programming model based on active power sensitivity. However, the active power sensitivity obtained by the DC power flow method ignores the influence of voltage and network loss, which makes the control strategy checked by AC power flow difficult to meet the accuracy requirement. For this reason, an online decision-making method for overload preventive control of transmission equipment based on the control objects relaxation is proposed. Firstly, the key equipment is determined by overload security margin, and the active power sensitivity of adjusting measures to key equipment under different post-fault operating conditions is calculated. Secondly, the active power adjusting measures are clustered. Thirdly, a linear programming model for overload preventive control online decision-making is established. Finally, the active power limit of key equipment is relaxed according to the active power accuracy of preventive control, and the search direction of the optimal solution is determined by AC power flow calculation. The correctness and effectiveness of the proposed method are verified through the analysis of the actual power grid.

This research tried to examine the effect of sense of control on moral judgments and the mediating roles of positive and negative affect. Sixty-one Chinese college students were randomly assigned to control-deprivation group and non-control deprivation group. After finishing an unsolvable 'concept-formation task', in which control deprivation was manipulated, participants rated sense of control, affective states, and made judgments in personal and impersonal moral dilemmas. Results showed that individuals in control deprivation condition were more likely to make utilitarian judgment in personal moral dilemmas rather than impersonal dilemmas. Furthermore, the negative affective states caused by control deprivation mediate the relationship between control deprivation and utilitarian moral judgment. Taken together, these results support dual-process model of moral judgment and control motivation theory., Author(s): Tianran Li [sup.1] , Fengqing Zhao [sup.2] , Guoliang Yu [sup.3] [sup.4] Author Affiliations: (1) grid.419897.a, 0000 0004 0369 313X, National Center for School Curriculum and Textbook Development, Ministry [...]

The academic underperformance of high school students with learning disabilities may reduce their access to higher education and decrease their employment opportunities. Based on stereotype threat hypothesis, the present study examined the role of stereotype threat in academic performance among adolescents with learning disabilities and the moderating role of psychological disengagement in this relation. In Study 1, 120 students with learning disabilities finished the measures of stereotype threat vulnerability and psychological disengagement, and their academic score at two time points were collected. Results showed that students who are more vulnerable to stereotype threat tend to have a lower academic score at Time 2 even after controlling for academic score at Time 1, and this relation was moderated by psychological disengagement. In Study 2, 62 sophomore students with learning disabilities finished measures of stereotype threat, academic persistence, and psychological disengagement. The results showed that the effect of stereotype threat on academic persistence was significant among students who were of low psychological disengagement, while this effect was not significant among students who were psychologically disengaged in academics. These results emphasize the individual differences of learning disabled students' response to stereotype threat and have significant implications for framing targeted interventions.

The instability of the winding-cushion structure is one of the primary causes of transformer failures. Insulation cushion compression and offset are the predominant forms leading to structural instability. Therefore, this paper, using the SFSZ7-31500/110 transformer as an example, first derives the theoretical formula for mechanical stress calculation. It clarifies the key influencing parameters of the winding-cushion block structure on the axial bending stress of the winding. Subsequently, an electromagnetic force finite element calculation model is established to obtain the axial force distribution in the winding and the distribution of unbalanced displacement during short-circuit processes. Based on the force and offset distribution, a specific cushion block compression and offset test platform is constructed. By setting different cushion block variables, the effects of cushion block unbalanced height and cushion block offset on the winding's bending elastic modulus are determined. Finally, a simulation model for stress calculation of the winding-cushion block structure is established, revealing the influence pattern of cushion block compression and offset instability on the axial strength of the winding. The results of this study indicate that the greater the uneven cushion block height, the lower the axial strength of the winding. Under the same cushion block offset angle, winding structures with non-uniform cushion block offsets exhibit the worst axial stability. When the offset angles are 30°, 45°, and 60°, the maximum axial bending stress of the winding increases by 1.73%, 3.46%, and 7.82%, respectively. Increasing the offset angle exacerbates the decrease in the axial strength of the winding up to a certain extent. The findings in this study have significant implications for enhancing a transformer's short-circuit resistance. [ABSTRACT FROM AUTHOR]

The basic characteristics of electric vehicles are important basis for studying the behavior of electric vehicles. According to the basic characteristics of electric vehicles, this paper establishes an electric vehicle convergence model and its control strategy with demand-side response. Taking into account the demand for electric vehicles, electric vehicle aggregators and power companies, reducing the cost of control, while reducing the impact on electric vehicles. Based on the real-time state of charge, the conditions of electric vehicle in the network and other factors to build the assessment model of the scheduling potential, and then put forward the demand response indicators of electric vehicles, and give the corresponding aggregation strategy. considering the multiple constraints , such as the cost constraints of electric vehicles participating in grid regulation, the charging requirements of electric vehicle owners, and the battery consumption of electric vehicles, a control strategy model is proposed for electric vehicles participating in demand response of power systems. The simulation test shows that the aggregation strategy can not only meet the travel needs of electric vehicle owners, but also reduce the impact on the electric vehicle caused by frequent switching of charge and discharge status. In addition, it can also reduce the cost of grid regulation.

This study investigated the effect of hollow 304 stainless-steel fiber on the corrosion resistance and mechanical properties of ultra-high-performance concrete (UHPC), and prepared copper-coated-fiber-reinforced UHPC as the control group. The electrochemical performance of the prepared UHPC was compared with the results of X-ray computed tomography (X-CT). The results reveal that cavitation can improve the distribution of steel fibers in the UHPC. Compared with solid steel fibers, the compressive strength of UHPC with hollow stainless-steel fibers did not exhibit significant change, but the maximum flexural strength increased by 45.2% (2 vol% content, length–diameter ratio of 60). Hollow stainless-steel fiber could better improve the durability of UHPC compared with copper-plated steel fiber, and the gap between the two continued to increase as the durability test progressed. After the dry–wet cycle test, the flexural strength of the copper-coated-fiber-reinforced UHPC was 26 MPa, marking a decrease of 21.9%, while the flexural strength of the UHPC mixed with hollow stainless-steel fibers was 40.1 MPa, marking a decrease of only 5.6%. When the salt spray test had run for seven days, the difference in the flexural strength between the two was 18.4%, but when the test ended (180 days), the difference increased to 34%. The electrochemical performance of the hollow stainless-steel fiber improved, owing to the small carrying capacity of the hollow structure, and more uniform distribution in the UHPC and lower interconnection probability were achieved. According to the AC impedance test results, the charge transfer impedance of the UHPC doped with solid steel fiber is 5.8 KΩ, while that of the UHPC doped with hollow stainless-steel fiber is 8.8 KΩ. [ABSTRACT FROM AUTHOR]