The temperature change of the power transmission line and substation equipment can reflect their potential safety hazard caused by their aging and overload. Based on the nonlinear analysis of forecasting substation equipment temperature data can realize effectively early warning of equipment failure and avoid huge losses caused by the accident. This paper puts forward a method for temperature forecasting, based on the chaotic time series and BP neural network. It collects data from wireless temperature sensors to establish a time series of substation equipments’ temperature. Software simulation results showed that the prediction method has higher prediction accuracy than that of the traditional method.
Since the rapid development of the construction industry, the production of construction waste has also multiplied, and the construction waste has caused tremendous pressure on the environment. Therefore, the main research of this subject is that the waste concrete is formed into a recycled material after a certain treatment--concrete powder. And the cement in the dry-mixed mortar is replaced by 0-30% concrete powder. The compressive strength of recycled concrete powder under different dosages was tested by experimental method. The compressive strength is then applied to the artificial neural network to establish a predictive model. Taking time as a variable, the feasibility and the best dosage of the 28-day compressive strength method for the 3d compressive strength during the test are discussed. In order to reduce the test cycle, improve work efficiency, and ultimately achieve the purpose of improving construction waste utilization.
According to the needs of the intelligent substation construction, this paper applied the optical fiber sensor technology and wireless sensing technology in the substation monitoring, and designed the substation equipment temperature information acquisition system and communication optical cable monitoring system, which connects to the power supply bureau monitoring center networking and provides the decision-making basis for the substation state control and maintenance. It is conducive to improve the level of substation intellectualization and information sharing.
In order to investigate the effect of confining pressures on rock dynamic fracturing under dynamic loads, a 2D finite difference dynamic numerical model for a circular rock sample with a single centralized borehole is developed. According to the material properties and loading conditions, shock and linear equations of state are combined and applied to the rock material in this model. A modified principal stress failure criterion is applied to determining material status. It is shown that as the increase of mining depth, the extent of blasting-induced damage of rock increases significantly.
Optical sensors are commonly used and most of them detect the variation of light intensity and then if there is the uctuation of light source intensity or change in propagation loss it causes measurement errors. A ring laser sensor is one of the potential candidates which are insensitive to such uctuation, but it has mainly two problems. One is lock-in effect and the other is insensitiveness to detect the sign (polarity) of the sensing signal. To solve these problems a new phase control system has been proposed. It consists of two polarizers, two quarter-wave plates, and one Faraday rotator. Using this system the phase is controlled by the simultaneous rotation of two quarter-wave plates.
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