Embodiments of this application disclose a method, an apparatus, and a system for information transmission in a PLC network. A switch control apparatus in embodiments of this application includes a switch and a coupling circuit. The coupling circuit is connected in parallel to two ends of the switch. When the switch is open, the coupling circuit transmits a first power line communication (PLC) signal to a gateway device. In embodiments of this application, when the switch is open, the PLC signal may be sent to the gateway device and information such as power off and tripping may be reported to the gateway device.