Xie F.,Guangdong Zhuhai Jinwan Power Company Ltd |
Wang X.-M.,Substation Overhauling Company
Dianli Xitong Baohu yu Kongzhi/Power System Protection and Control | Year: 2010
This paper studies the defects of security constraints control strategy of AVC sub-station system in power plants and proposes a new optimized control strategy. Remote control mode and local regulation mode are combined in the optimized control strategy. Ordinarily, AVC sub-station system is controlled under remote control mode by master. When some important parameters are over limited, local regulation authority is opened, and reactive power can be regulated reversely. The optimized control strategy improves the voltage regulation performance of AVC sub-station system, eliminates the hidden danger of the power coupling, and enhances the security and stability of the generating units. The reactive power control demand of the grid and the voltage security of the power plant are organically combined in the optimized security constraints control strategy of AVC sub-station system.
Zou Y.,Wuhan University |
Liang S.,Wuhan University |
Peng D.,Wuhan University |
Peng D.,Guangdong Zhuhai Jinwan Power Company Ltd |
Zou L.,Wuhan University
Jianzhu Jiegou Xuebao/Journal of Building Structures | Year: 2011
With the height of highrise buildings increasing, the natural periods of the lower modes become longer, and the contribution of the second mode to wind-induced dynamic responses of the buildings increases. The contribution of the second mode was analyzed through a large number of illustrative examples. The calculated results indicate that the contribution of the second mode to the dynamic displacements of high-rise buildings in across-wind direction is rather small. However, its contribution to the acceleration of super-highrise buildings in across-wind direction can not be neglected. Therefore, the contribution of the second mode should be considered when the comfort analysis of wind-resistant super-highrise buildings is conducted. In addition, based on wind tunnel test data and random vibration theory, simplified empirical formulas for the evaluation of across-wind induced dynamic responses of rectangular tall buildings, were derived with the consideration of the second mode contribution. The comparison between the results estimated by the formulas and those obtained by complex integral calculations show that the errors between them are basically within 5% for all cases. Thus the formulas proposed in this paper are very acurate.