| The contradiction between the unbalanced power resources of the eastern and western parts of China is being solved by HighVoltageDirectCurrent,HVDC technology because of the great aventage of high voltage,high-capacity,long distance power transportation.However,the China Southern Power Grid also make up a huge power network which is mixed with AC and DC interconnection,high-capacity,dense,and complex.To ensure safe and stable operation of HVDC,advanced HVDC protection is the most important guarantee.Once a device fails,the correct operation of DC protection can quickly isolate the fault and avoid the expansion of the accident.If DC protection fails to operate correctly,it will inevitably result in equipment shutdown or even expansion of fault scope.In the long term operation and maintenance experience,the characteristics of long distance transmission lead to the vast landform and meteorology of the transmission lines,and the external operating environment is very complex.In the long term equipment operation and maintenance experience,the equipment failure is almost unavoidable.However,the characteristic of HVDC power transmission capacity determines that once the DC protection action occurs,the huge power will be excised,which can easily cause the shock of the terminal power grid and even collapse.Even if an instantaneous fault occurs,if the fault can not be quickly eliminated and the power transmission is restored as soon as possible,the transmission enterprise also suffers great economic losses.Therefore,whether it is the requirement of the stable operation of the power grid or the angle of business operation,the most critical should be raised as far as possible in the accident of the HVDC transmission system.HV DC relay protection accident handling efficiency,rapid processing of failures,as soon as possible to restore power transmission capacity,to ensure safe and stable operation of the system.Therefore,this paper puts forward some practical measures to improve the efficiency of HVDC relay protection accident treatment,shorten the time of DC protection accident treatment and shorten the DC outage time.The main work of this article includes:The efficiency of DC protection accident treatment is determined by two factors: the correct rate of accident treatment and the time of accident treatment,in which the correct rate is proportional to the efficiency,and the relationship between time and efficiency is inverse proportion.Only by correctly analyzing the cause of the accident and shortening the time of handling the accident can we really improve the efficiency of accident handling.This subject takes the typical DC protection trip of UHVDC(UltraHighVoltageDirectCurrent)and UHVHVDC power transmission project over the years as the research object,studies the cause of DC protection trip,and summarizes the practical measures of DC protection accident treatment.The study found that the five measures to improve the efficiency are to analyze the correct action of protection,to quickly query the fault point of the hardware circuit positioning protection device,to sort out the fault tree in the past years,to improve the fast response speed of the information of the shared factory,and to form the management closed loop of the electronic management trip report.In order to meet the requirements mentioned above,a software design scheme is proposed,and a set of auxiliary decision system for accident handling of DC protection is developed to meet the needs of the site engineers to analyze the cause of the accident,to query the hardware circuit,to manage the defects,to share the information of the factory and to manage the trip report.The typical DC protection trip of HVDC and UHVDC transmission projects under the China Southern Power Grid Co.,Ltd.EHV Transmission Company Guangzhou Bureau is the research object.The cause of DC protection trip is studied.The practical measures for the accident treatment of DC protection are summarized.A software design scheme is proposed to meet the needs of the engineers to analyze the cause of the accident,to query the hardware circuit,to manage the defects,to share the information of the manufacturer and to manage the trip report.This article is supported by the mass innovation project of the Guangzhou Bureau of ultra high pressure Transmission Companies("Research project on practical measures to improve the efficiency of DC accident treatment").Some of the research results have been applied in the Guangzhou Bureau of ultra high pressure Transmission Companies,which has obtained good technical and economic benefits,and verified the correctness and effectiveness of this work. |
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