The connection filter is designed for connection of equipment of high-frequency channels of relay protection, emergency automation, telephone communication and data transmission to phase wires of overhead power lines with voltage 35 - 750 kV.
- transmission of high-frequency signals from high-frequency channel densification equipment to and from the high-voltage line (HV line);
- suppression of the industrial frequency signal from the communication capacitor (CC);
- harmonisation of overhead line impedances and communication equipment;
- ensuring electrical isolation between overhead line circuits and input circuits of communication equipment;
- protection of communication equipment from overvoltages occurring in overhead lines during switching processes and lightning discharges.