Study On Dynamic Reactive Voltage Optimization Strategy Of UHVDC Transmission In Wind Power Base

With the continuous depletion of fossil energy,searching for new alternative energy to meet the growing demand for energy,it is an important issue to face at the present stage of China.In response to the call of developing low-carbon economy and optimizing the transformation of energy structure,wind power stand out from many new energy power generation technologies because of its unique low pollution,renewable and easy access.At present,wind power has become one of the most mature and most developed power generation modes in China.Therefore,the proportion of wind power in energy structure is increasing rapidly.This paper focuses on the northwest weak sending grid which wind power base transmission based on the UHVDC,aiming at DC system voltage problem after DC blocking power transfer and a large number of redundant reactive power.Studying the dynamic characteristics of reactive power voltage after DC blocking,propose the optimization strategy of WTG overvoltage tripping,system dynamic supporting and bus steadystate voltage riseThis paper summarizes the influence factors of wind power base through UHVDC transmission system voltage the status of dynamic factors,first analysis voltage characteristics of power under the DC blocking,in a typical system,set up three ways to explore transient atresia after DC blocking including transient voltage rise,dynamic voltage support and steady-state voltage rise.Combined with the characteristic results and the actual operation conditions of the power grid,the corresponding plans for improving the above three voltage problems are worked out to improve the dynamic reactive power and voltage level under DC blocking.The main contributions of this paper are as follows:1,Based on the simulation software PSD-BPA,build the wind power base model of UHVDC transmission system,including the single machine model,the electric field equivalent model,the SVC model,the thermal power unit model and the HVDC transmission system model.2,First,based on the mechanism of DC block,transient voltage rise characteristics are analyzed;then construction AC/DC equivalent system,combined with the impact of AC grid power angle curve,analysis the influence of dynamic voltage support system transient stability mechanism;finally,perspective from the physical exchange of AC channel steady pressure rise.In typical system,the above characteristics are verified by three ways: DC blocking do not cut machine,DC blocking do not cut machine resected,and DC blocking cut reactive compensation.3,According to the transient voltage rise mainly through the thermal power and decline DC power control strategy for dynamic optimization;reactive power compensation cutting scheme of dynamic voltage is formulated,simulation results show that cutting priority;combined with controllable configuration in practical engineering of high resistance improve the steady-state voltage rise.