Research On Operation And Maintenance Strategy Of Converter Valve Cooling System Equipment In Power Grid Converter Station

HVDC transmission technology has the characteristics of high voltage level,large capacity,long transmission distance and easy grid interconnection.In recent years,it has developed rapidly in my country and has become a key means of long-distance transmission.The converter valve is the most critical device to achieve AC/DC conversion in DC transmission.It is subjected to large current and high voltage during normal operation.The efficient and stable converter valve cooling system can effectively perform the capacitor and resistance components in the valve tower.Cool down.According to incomplete statistics,single and double pole lockouts due to the failure of the converter valve cooling system account for 20% to 25% of the total number of accidents.Therefore,analyzing the failure of the valve cooling water system,performing early warning of the defect function,and studying the operation and maintenance strategy can effectively reduce the number of outages of the HVDC system due to the failure of the converter valve cooling system,which is important for ensuring the safe and stable operation of the DC line significance.This paper takes the six converter stations in the Guangdong area of China Southern Power Grid as an example.The number of converter valve cooling system equipment is huge,and the number of equipment defects is large.According to the defect data statistics from January 2018 to the end of December 2019,valve cooling system defects account for 34% of all equipment defects.This paper will explain the principle of the converter station valve cooling system,introduce the structure of the converter valve cooling system and its main equipment,and compare the 423 of the 6 converter stations currently in operation from January 2018 to December 2019 in China Southern Power Grid.The defects of the valve cooling system are sorted and analyzed,and the faults are analyzed.At the same time,improvement measures are proposed based on the operation status of the valve cooling system equipment and operation and maintenance requirements.In the research of operation and maintenance strategy,establish a cooling capacity reserve quantitative model,and use the entropy weight method to calculate the weight of the cooling capacity reserve evaluation of the five indicators of water inlet temperature,expansion tank water level,conductivity,fan and main circulation pump,and cross-sections at different times Determine whether the cooling capacity of the valve cooling system can maintain the normal operation of the DC;at the same time,establish a multi-dimensional analysis of the converter station valve cooling system defect warning function,through the abnormal identification of the internal cooling water conductivity,inlet temperature and internal cooling water circuit leakage,Improve the sensitivity and accuracy of early signs of abnormal equipment.The cooling capacity reserve quantitative model and the multi-dimensional analysis of the converter station valve cooling system defect early warning function have been piloted in the multi-dimensional analysis and early warning system of a converter station,and the real-time cooling capacity reserve quantitative assessment and extreme engineering of the converter station are carried out.Cooling capacity check under conditions.