g参数修正法用于浙西±800kV换流站阀厅空气净距设计

Air Clearance Design for Valve Hall of Zhexi ±800 kV UHVDC Converter Station Using Parameter g

±800 kV特高压直流换流站的阀厅空气净距设计是特高压直流工程实施中的关键技术之一。由于换流站阀厅内部有空调系统调节,大气密度、温度、湿度等都不同于标准气象条件。为此,采用g参数法对非标准气象条件下空气间隙的放电特性进行修正。该方法基于大气密度修正系数k1和湿度修正系数k2,系数k1和k2由阀厅气象条件和因子m、w共同确定,而因子m和w则取决于参数g。由于参数g在获得时需要通过待求的空气间隙距离d,因此该方法在应用过程中需要多次迭代计算。研究结果表明,采用最新的g参数曲线得到的空气净距略小于按照以往曲线所得结果,且由于误差限制该方法适用于海拔≤2000 m的修正。将该方法应用在浙西±800 kV特高压直流换流站的阀厅空气净距设计中,得到了阀厅内主要位置的最小空气净距,其中直流侧高压母线对地推荐最小空气净距≥8.7 m。

The air clearance design of valve hall in ±800 kV UHVDC converter station is one of the key technologies of UHVDC project.The atmospheric density,temperature,and humidity are different from standard atmospheric conditions because of regulating by air conditionings installed in the valve hall.Therefore,the g-parameter method which corrects the discharge characteristics of the air clearance under non-standard atmospheric conditions is adopted.The method is based on air density correction factor k1 and humidity correction factor k2.Factors k1 and k2 are determined by atmospheric conditions and exponents m and w,which depend on parameter g.The iterative calculation process is needed in application due to the fact that parameter g must be obtained from air clearance d,which is to be solved.The results show that,by latest g curve,air clearance is slightly less than past,and the method is suitable for altitude less than 2000 m because of error.The method is employed in designing the Zhexi ±800 kV UHVDC converter station,and the air clearance of main locations in hall are obtained.The recommended air clearance of DC-side high-voltage bus is not less than 8.7 m.