| Due to the rapid increase of electrical load and the reverse distribution of energy and load centre, developing large-scale wind power and constructing ultra-high voltage (UHV) power transmission channel are necessary for China. Hubei Power Grid, which locates in the center of Central China Power Grid, plays an importantrole in UHV nationwide interconnection and wind power consumption. However, grid faults caused by appalling weather are threatening to the security operation of power system. Besides, rapid growth of load demands and large-scale penetration of wind power contribute to the growing load peak-valley difference of power grid, and so as to the more difficult peak regulation.Based on these concerns, this dissertation intends to evaluate the security and stability level of Hubei Power Grid under extreme weather conditions, and promotes a further study on the peak regulation of Hubei power grid with UHV transmission channel connection and wind power penetration.At first, on the basis of microclimate conditions, amultivariate linear regression model consisting of several meteorological elements is established for line icing thickness calculation. Considering altitude modified coefficient, the probability calculation model about the annual maximum value of transmission line icing thicknessis proposed. By employing this probability calculation model, the probabilities of transmission line tripping and tower failureunder different designed icing thicknesses are obtained. The ability of Hubei Power Grid to withstand the ice disaster is evaluated using venture analysis method.Secondly, by investigating and analyzing the technical approaches, power source types and available power capacity of peak regulation in Hubei Power Grid at2015,the maximum adjustable capacities for peak regulation on typical days of summer and winter are determined.On the other hand, the maximum peak-valley differences on the typical days are obtained through the study on daily load characteristics.With the comparison of maximum adjustable capacities and maximum peak-valley differences, the peak regulation ability of Hubei Power Grid is analyzed.Further more, a predict method for load curves is carried out, which regards the indicator of the load characteristics as restrictions and uses linear fitting method, least square, ARMA model and BP neural network to predict the degree of fitting of daily load curves. On this basis, the load forecast values is obtained using fuzzy technology sub-period approach. Inaddition, a peak regulation optimization strategies based on improved niche genetic algorithm is proposed, which can strike a global optimum result with the minimum network loss. Using the presented load curve forecasting methods and peaking regulation optimization strategies, the peak regulation scheme of Hubei Power Gridin2015, corresponding the scenario that only the thermal power is transmitted through UHV transmission channel, is obtained and further compares with the traditional peak regulation scheme in the aspect of economy.At last, two scenarios of power transmission through UHV transmission channel are considered, the former refers to that the wind power bundling with thermal power is transmitted and the latter represents that a fixed percentage of generated wind power is transmitted. The comparative study on the impact of above two scenarios to peak regulation in Hubei Power Grid is analyzed. For the latter scenario, the peak regulation schemes responding to different wind power percentages are obtained to cope with the wind power variation and power load change. The peak regulation schemes take full advantage of the regulation characteristics of the thermal power units and pumped storage units. Additional, the network lossis effectively reduced with no deterioration of the system security. |
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