| With the increasing demand for energy,the use of HVDC transmission technology is becoming more and more extensive.Long distance transmission of super large scale electric energy,efficient grid connection for renewable energy generation and improvement of the flexible and controllable level of power grid are implemented by high voltage and large capacity power electronic equipment,such as HVDC converter valve.Converter valves are the most important components in DC transmission technology,which is used to convert AC to DC and control its output power.A lot of heat will be released when converter valve is operated.Deionized water is often used as a coolant for converter valve because of its good characteristics such as high specific heat,high thermal conductivity and high voltage withstand.However,due to the different environmental conditions such as different material,pH,water temperature,dissolved oxygen content,flow velocity and ionic impurity,the electrode of cooling system is chemically corroded,causing serious accidents such as clogging,water leakage and even power failure.At present,the operation fault of the cooling water system of the converter valve in China accounts for 70%of the total fault of the converter station.There is a great chance of valve plates,reactor,damping resistors to be burnt out.In recent years,the problem of corrosion and deposition in the water cooling system of the converter valve greatly restricts the development of DC transmission technology.In this paper,the corrosion and deposition of water cooling system of converter valve are studied.In the experiment,the water sample data is analyzed by the experimental platform of the water cooling system of the converter valve.The electrochemical workstation is used to measure the electrochemical parameters of the electrode under different conditions by using the three electrode method.In theory,the electrode surface electric double layer model is established;the secondary current field is compared with constant current field by suspended aluminum block model;The double electric layer model and the secondary current field are combined to solve the electric double layer capacitance in the actual situation;the dilute material transfer field,the secondary current field,the fluid field and the double layer calculation method proposed in the previous paper are used to analyze the deposition of the water system.According to the results of the study some corresponding improvement measures of water cooling system of the converter valve are given. |
