详细介绍：

the numerical line fault detectors DDL800-R and DDL800-T perform the protection of 500VDC to 3500VDC railway lines. Faults on electrical network are mainly determined by “over current” or “rate-of-rise di/dt” functions. Many additional functions allow easy management of electrical network.

Main functions

• Overcurrent protection* [76-1] [76-2]
• Rate-of-current rise protection (di/dt)
• Delta I current step protection (ΔI)
• De-icing differential protection

Additional functions

• Presence and lack of catenary voltage (DDL800-R only)
• Substation and catenary voltage comparison (DDL800-R only)
• Voltage drop monitoring (DDL800-R only)
• Catenary voltage monitoring [27DC] [59DC] (DDL800-T only)
• Upstream current detection (monitoring of the current flowing to the
substation)
• Cable thermal image [49DC]
• Four shot recloser [82]
• High speed circuit breaker failure [76BF]
• Sensors monitoring
• Programmable line test before reclosure (with optional EDL interface, see
application guide)

*directional operating mode: user configurable see characteristics
In addition to the protection functionalities, the DDL800 provides monitoring, measurement
and recording of the electrical quantities of the network.
The relay can be set locally, using either the keyboard / screen, via RS232 or remotely using
the RS485 port.
Setting, reading, measurement and recording are all available locally or remotely.