directional earth-leakage relay

例句：

1. 1. The directional earth-leakage relay is an important component of the electrical system.
   方向性地漏电继电器是电力系统中的一个重要组成部分。
2. 2.The directional earth-leakage relay was designed to protect against electrical faults.
   方向性地漏电继电器被设计用来防止电气故障。
3. 3. The directional earth-leakage relay is used to detect and isolate faulty circuits in the power grid.
   方向性地漏电继电器用于检测并隔离电网中的故障电路。