238 results about "Annual average" patented technology

The invention discloses a method for evaluating the economic operation year range of a transformer substation. According to an original fault rate model based on Weibull distribution or index distribution, only the service age is taken as the variable, various other factors influencing the fault rate of the transformer substation are not considered, and thus the original fault rate model is not suitable for being taken as a model for predicting the fault rate of the transformer substation. According to the method for evaluating the economic operation year range of the transformer substation, the transformer substation is evaluated comprehensively in the aspects of the operating environment and the quality condition, the influence of the two factors on the defect-level fault rate, the invalid-level fault rate and the accident-level fault rate of the transformer substation is analyzed by means of a least square support vector machine under the condition that the different operating times of the transformer substation are considered, the annual maintenance cost range and the fault cost range of the transformer substation under the conditions of the three types of fault rates are obtained by combining the interval analysis method and the whole life cycle cost theory, and finally the operating year range in which the annual average cost of the transformer substation is lowest is taken as the economic operation year range of the transformer substation. The method can provide beneficial guidance for decisions such as power grid planning and transformer substation transformation.

The invention aims at providing a wind turbine generator system low-wind-speed airfoil section family. The airfoil section family is mainly used for the area with the low wind speed of 5 m/s to 7.5 m/s and is composed of six airfoil sections including the first airfoil section, the second airfoil section, the third airfoil section, the fourth airfoil section, the fifth airfoil section and the sixth airfoil section, wherein the maximum relative thicknesses of the airfoil sections are different, the maximum relative thicknesses of the first airfoil section, the second airfoil section, the third airfoil section, the fourth airfoil section, the fifth airfoil section and the sixth airfoil section each range from 15% to 35% from the blade tip portions to the blade root portions, and each airfoil section comprises an S-shaped pressure face. All the airfoil sections are blunt trailing edges. The design Reynolds number of each airfoil section is 1*10<6> to 4*10<6>. The design attack angle of each airfoil section is 6 degrees or 7 degrees. The airfoil section family is mainly used for most of the regions, with the wind power density level of 2 to 4 and the annual average wind speed of the 50-meter-high position ranging from 6.4 m/s to 7.5 m/s, in inland China, and the wind energy utilization rate of blades in low-wind-speed areas can be increased.