± 1100 kV 换流站直流场防雷设计研究

Ｒesearch on Protection Design against Lightning for DC Yard of ± 1100 kV Converter Station

摘要:

± 1100 kV 是特高压直流输电工程中的全新电压等级，± 1100 kV 换流站设计尤其是换流站中直流场的设计 面临许多全新的挑战。这里对防雷设计的方法进行了对比研究，确定使用滚球法进行防雷设计，同时提出了击距系 数的取值，确定了直流场各个区域的击距。提出了 ± 1100 kV 换流站直流场防雷具有 4 个方面的特殊性: 较大的空气 净距要求与相对较小的雷电击距的矛盾; 小雷电流保护区域范围扩大; 直流场空间受限; 难以确定“危险剖面”。通过 上述研究提出了适用于 ± 1100 kV 换流站直流场，利用空间上多根相交或不相交的避雷线及耐受雷击较强的导体联 合保护，构建一种具有空间层次结构的防雷方案。并提出了采用三维建模进行工程校验。

Abstract:

± 1100 kV is a brand new voltage level for HVDC transmission project，the design for ± 1100 kV converter station， especially for its DC yard，is full of new challenges． Different calculation methods for protection against lightning are compared，and the rolling sphere method is confirmed as the design tool，meanwhile，the strike distance factor is also proposed and then the strike distance is figured out． The particularity of the protection design against lightning for ± 1100 kV DC yard is considered as below: a) the contradiction between the large air clearance requirement and the small strike distance; b) the area with small lightning protection current is enlarged; c) the space of DC yard is limited; d) it is quite difficult to figure out a " risky section" ． According to the above － mentioned design principles and the features of ± 1100 kV DC yard，a protection plan against lightning is proposed which utilizes multiple shielding lines or conductor that can withstand large lightning current ( intersected or not) to form a joint protection，and establishes a protection plan against lightning with layered structure． The proposed plan is evaluated with 3D modeling．