DDL800 provides surveillance of catenary wire outputs on direct current networks. It is dedicated to tram and rail applications.

It acts according to variation criteria or current thresholds and offers a de-icing monitoring function. It also includes voltage protection and many operating functions such as thermal image (cable), a recloser with management of the sub-station and the verification of the correct operation of the ultra fast circuit breaker.

In addition to the protection, the EDL line test device monitors the disappearance of the fault before authorising the closure of the circuit breaker.