cupling unit

Dear Guest,

Power Line Carrier communications are used for safe and efficient operation of high-voltage power networks and allow for the transmission of tele-protection signals, speech and SCADA data.

A power line carrier system includes basic elements: a transmission line, presenting a channel for the transmission of carrier energy; tunning, blocking, and coupling equipment, providing a means of connection to the HV transmission line, and PLC equipment (transmitters/receivers, relays,etc.).

Line traps provide blocking of the carrier signal, preventing it to be directed to the station bus. Depending on the importance of the line, the scheme of coupling could be of Single Line to Ground (one line trap on the middle phase) for TL with less importance, or Phase to Phase (multi-phase coupling) to improve the dependability of the signal being transmitted through fault, for TL with significant importance.

Coupling capacitor is used as part of the tunning circuit. It provides a low impedance path for the carrier energy to the HV line, and at same time blocks the power frequency current by being high impedanc path.

Line tuners in conjunction with the coupling capacitor provide a low loss path of the power line for the carrier signal. The line tuner should be mounted either in the base of the coupling capacitor, if space is available, or on the structure that supports the coupling capacitor. The reason is that the lead between the coupling capacitor and the tuner should be as short as possible to avoid losses and frequency disturbances.

Regards,