Research On High Frequency Incentive Ice Melting Technology And Device For Ice-Covered Transmission Lines

Icing on transmission lines in winter may endanger power facilities and affect the safe operation of power systems.In 2008,the ice disasters suffered in southern China caused tremendous damage and losses to the power system and the national economy.So far,the field of power systems,especially in the domestic set off a transmission line icing and mitigation technology boom.The high-frequency and high-pressure incentive ice-melting technology as one of the development directions of new ice melting technique,with high efficiency of melting ice and can be achieved online icing,etc.,very promising in the future icing mitigation techniques.However,related theories need further study,and the apparatus applicable to the ice melting method is still to be developed.In order to deal with the problem of high-frequency melting ice,the dissertation first studies the skin effect and the dielectric loss characteristics of ice at high frequency.The icing conductor calculation model was established with a single conductor model,and under this model,a uniform transmission line theory was used to discuss the determination method of ice-melting excitation source parameters without considering the power attenuation of melting ice and considering the power attenuation of ice melting.Taking the actual ice-covered conductor as the research object,the feasibility of ice-melting source ice melting parameters was calculated and analyzed.Based on the determined parameters of the high-frequency melting ice excitation source,AC-DC-AC current converters are used as cascade ice melting excitation source circuit topology,and carrier phase shift technology is used as a converter control method to design a high-frequency ice melting excitation source device;and a series adjustable capacitor is designed in the ice melting circuit to adjust the equivalent impedance of the ice-melting circuit and compensate the reactive power to reduce the excitation source capacity.On the basis of the above research,in accordance with the design requirements of the ice-melting excitation source,the parameters of the ice-melting excitation source devices are determined.In MATLAB,a device simulation model was set up to simulate different types and lengths of ice-covered conductors.The parameters such as voltage,current,capacity,and harmonics of the input and output of the ice melting device were analyzed.And compared with the design requirements,verified the feasibility and scope of application of high-frequency ice melting device design.The high-frequency melting ice excitation source device researched in this dissertation can output high-frequency voltage according to the requirements of high-frequency melting ice,and has low harmonic content and large capacity;A single power unit can obtain a higher advantage of the equivalent frequency at a smaller operating frequency,which solves the difficulty of the existing high power devices that have a low switching frequency and are difficult to output a higher frequency;the proposed adjustable capacitor in series in the ice melting circuit solves the problem of high reactive capacity requirement and flexibility for ice melting devices.Above that,the research results have important theoretical reference value for the practical application of high-frequency incentive ice-melting technology.