In general, the power engineer adopts fixed value of Basic Lightning Impulse Level (BIL) as equipment specification, and put lightning arrester at the joint of tower and underground cable.

• 在变电所之系统设计上，设备绝缘等级是采用传统固定式的基本雷击脉冲准位(BIL)来作为规范，而避雷器是固定安装于地下电缆的入口端的位置。