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Because the environment that the wind turbine runs in is severe, the generating efficiency is low and the vibration of tower is very obvious. The consequence not only causes economic loss but also lead to the reduction of the wind turbine's lifetime. Basing on the traditional PI controlling system, this passage mainly studies to decrease the vibration of the tower by adjusting the controlling PI parameters...
Preliminary research of AC breakdown voltage of thermal bubble induced two-phase flow condition of inflammable fluorocarbon by self-heating plane-plane electrode has been reported before. Further breakdown experiments by sphere-plane electrodes with different gap distance and working pressure have been accomplished in this paper. According to the experimental outcomes, the AC breakdown voltage of...
Decades of experience in urban underground substations indicated that the traditional cooling technologies have various disadvantages. Therefore, a novel loop heat pipe (LHP) cooling system was developed and applied in a power transformer. This cooling system is self-circulated, without needing additional pump or fans installed in transformer. At first, a 2.5kW experimental model is fabricated and...
Software which could plot electric force line with tangent method (Euler Method) has been developed based on APDL language. The plotting program has been applied to the calculation and optimization design of the main insulation electric field of power transformer. It could calculate the average electric field strength and the insulation margin value of every oil gap on the electric force line one...
The paper analyses the main issues and the key technologies which need to be solved of the electrostatic precipitator (ESP) energy saving control. On the basis of analyzing many ESP on-site operation data and the voltage-current curves, we developed a new type energy saving control system by combining a lot of ESP performance tests comparison and technologists’ experiences. The new system is a closed-loop...
To improve the control performance of the position sensorless interior permanent magnet synchronous motor (IPMSM) drives, an active flux model based full-order discrete-time sliding mode observer (DT-SMO) is proposed. Bearing in mind the modeling uncertainties and external disturbances, the observer design and the stability analysis are given. To reduce the inherent chattering problem of the sliding...
Because of its high dielectric strength, good partial discharge capability, low global warming potential (GWP), none ozone depletion potential (ODP) and no toxicity, fluorocarbon gases(c-C4F8 and its mixture with N2) are possible substitute for SF6, and can be used in electrical equipment. Gas insulated switchgears and transformers using fluorocarbon gas mixtures as dielectric and coolant are new...
This paper takes the energy savings as assessment criterion for Combined Heat Cooling and Power System, analyzes the conditions CCHP needs to meet in comparison with dispersed generation. Generating efficiency of cogeneration and the effects thermoelectric ratio has on energy-saving performance are analyzed as top priority.
Traffic conflict studies have been widely used because the data of traffic conflicts can be collected and evaluated in a short period of time. Widespread studies have shown that there is close relationship between traffic accidents and traffic conflicts. Since the data of traffic accidents are usually inadequate and the application of traffic accident analysis often requires long periods of data accumulation,...
The thesis emphasizes in analyzing the thermal environment of top-floor rooms and energy consumption of various roofs. Through the application of the mathematical model based on DOE-2 software, the author simulates and calculates the thermal environment of top-floor rooms and energy consumption of various roofs for seeking the roofing type and the roofing structure that harmonize with the climate...
According to connectionism theory, words do not exist in isolation; but always form structural sets of elements together with other conceptually related words that have a reciprocal influence on each other, and word meanings are defined through the sense relations. By constructing sense relations of words, semantic sets are established which give great precision in guiding students towards meaning...
There are many kinds of methods to estimate the energy requirement or fuel consumption in the optimal design and minimize the life cost of a building. The bin method is one of the most popular ways to estimate the energy performance of a building, which is based on the hourly-based outdoor dry-bulb temperatures of all days in a whole year. There is lack of information about the bin weather data in...
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