Apply to protect electrical relay, POWER, amplifier and so on.

用于继电器、电源、放大器等电器元件保护。

youdao

The church was crowded, so electrical machinery was used to relay the service out to the people.

教堂里挤满了人，所以就用电机设备把礼拜仪式向外面的人转播。

《新英汉大辞典》

youdao

Entergy told New Orleans City Council members that the company still doesn't know why the device triggered, but the relay has been removed, the dome's electrical system is ready to go and steps will be taken to ensure a malfunction doesn't happen again.

CNN: STORY HIGHLIGHTS

That led the relay, a kind of sensing device, to incorrectly conclude there was an electrical problem and tell a nearby electrical switch to isolate the perceived problem, reducing the flow of power to the Superdome during the game's third quarter.

WSJ: Device Setting Triggered Super Bowl Outage