DEFINITION OF RANDOM VARIABLES “AVERAGE WIND SPEED” AND “ANNUAL WIND ENERGY POTENTIAL” ON THE BASIS OF LONG-TERM WIND SPEED MEASUREMENTS AT METEOROLOGICAL STATIONS ON SAKHALIN

Abstract

According to measurements at meteorological stations, average annual wind speed on Sakhalin Island varies from 2 to 9 m / c. The average annual wind speed throughout Russia is in the same range. Therefore, the study of power characteristics of the wind on Sakhalin must give general wind energy properties throughout Russia. Processing of weather stations data has been carried out using the new approach. This methodology is based on the hypothesis that the wind speed at an arbitrary interval in time is a continuously differentiable function of time V ∞ (t) . It is assumed that the function V ∞ (t) is the result of such random process, when in regular intervals Т in the identical conditions this function keeps the continuity, differentiability, and has a large number of extrema, but quantitatively changes each time a little differently. Energy properties are characterized by an average wind speed and potential of wind energy. At the same time, unlike the meteorological tradition, potential of wind energy is defined as the energy of the air stream across a unit cross-sectional area at a given time interval Т . Such a definition of wind energy potential is necessary, because the performance of wind turbines in the time interval Т is determined by the value of the wind energy potential, defined for this time interval. A number of cyclic periods of time allows us to get a sample of random variables characterizing the properties of wind energy. For this sample on the base of methods of mathematical statistics the probability density function and the root mean square deviation of these random variables are determined. As a result of statistical processing of wind speed measurements at meteorological stations of Sakhalin, empirical probability density functions of random variables “average wind speed” and “annual wind energy potential” have been identified.