The digital differential protection relays NPDT620 and NPDT630 are designed to provide fast and selective protection of 2 and 3-winding three-phase transformers.
The NP600 relays can detect various types of fault in the zone to be protected, such as phase-phase faults, inter-winding faults and earth-fault.
Restricted earth-fault protection (REF), on primary and secondary sides, is available as an optional function for 3-winding transformers.
In addition to the protection functions, NPDT relays also perform monitoring, measurement and recording of the electrical quantities of the network.
ANSI functions:
87T / 64REF (option for NPDT 630) + Buchholz and temperature monitoring via digital input.
These relays allow communication via Modbus RTU (RS485). A full brochure is available on the Railway Industry page.