| The icing of transmission line is a serious threat to power system,all kinds of ice accidents seriously endanger the safe operation of power system,greatly reduce the reliability of power supply,and cause huge direct and indirect economic losses.The research on the melting technology of transmission line has been carried out,the thermal melting ice is the main method,and the ice-melting scheme,which is supplemented by mechanical deicing,is applied in most deicing engineering.The more mature technology of thermal melting ice is DC short circuit melting ice and AC short circuit melting ice,however,although the former can be used for high pressure long-distance line melting ice,but the need for the cost of DC ice-melting power is high,economic needs to be improved,the latter for the ice-melting power supply to provide too much reactive,generally applicable to 220kV and below voltage grade lines.High-frequency excitation melting method is a new method of melting ice,which differs from the traditional thermal melting method,which can not only achieve the thermal power of melting ice with small current,but also can be heated evenly along the line.In this paper,the principle of high frequency melting ice is further studied,and a dynamic ice melting model is put forward on the basis of research group,and the influencing factors of high frequency ice melting method are discussed,and compared with the AC/DC short Circuit melting ice.Firstly,the basic principle of high frequency excitation melting method is introduced from the structure and dielectric properties of ice and the skin effect,and the basic principle of finite element method and its application in melting ice problem are introduced in detail.Then,this paper perfects the concentric static model of ice-covered conductor used in the subject group,describes the high frequency melting process by dynamic model,and establishes equivalent circuit which is the same as the theoretical model of uniform transmission line.Then,on the basis of establishing the physical model and equivalent circuit model of high frequency ice-melting,the thermal process in high frequency melting process is studied and the parameters of high frequency excitation ice-melting method are selected.After the model is established and the parameters are selected,the feasibility of the high frequency melting ice is verified by the finite element analysis software Ansys.Then,according to two indexes of critical ice-melting current and melting time,the influence factors of high frequency excitation melting method are further discussed.Finally,the characteristics of high frequency excitation melting method are introduced theoretically.The simulation results show that the high frequency ice-melting excitation method is compared with the AC/DC short-circuit melting ice,which reduces the melting time and reduces the critical melting current,while saving the time of melting ice,Reduce the demand for ice-melting incentives.Based on the research of this topic group,the principle,analysis method and influencing factors of high frequency excitation melting ice are studied further,and compared with traditional thermal melting method from melting ice principle to melting ice effect.It is of great significance for the further development of the high frequency excitation ice-melting method,and a new solution is proposed for the icing problem of the transmission line. |
