Equipping signal technology systems with lightning protection under consideration of safety aspects

As more and more electronic and digital signal boxes are being used in railway infrastructure, an increasing number of sensitive electronic devices are found in control command and signaling technology. To protect them against lightning and transient overvoltage, surge protective devices are installed as lightning protection. Because lightning protection is looped directly into the signal circuit, it is imperative to take a number of safety aspects into consideration.

The surge protective devices must remain impact-free, meaning they must operate impedance-neutrally in a parallel path to all signal lines. The power they require must not be drawn from the signal path. The status indicator must function independently of the signal status. Residual currents that endanger operations in any way are not permitted. Installing or removing the surge protective devices may never lead to an interruption of the signal circuit; in simple terms, ongoing operations may not be adversely affected. Manufacturers must make the relevant parameters available for creating the safety documentation.

Phoenix Contact provides solutions that satisfy these requirements and comply with the relevant Deutsche Bahn directive, DB-Richtlinie 819.0808.