2.4 Distance protection Z<
2 Protection functions
Technical description
56
VAMP 24h support phone +358 (0)20 753 3264
VM259.EN007
Teleprotection signals
Signalling between two distance protection relays
(teleprotection) can be implemented using the normal DI and
DO signals of the relay. An external signal transfer system is
needed to transfer signals from one relay to another. The
signal transfer system has to have an internal signal
supervision and fault indication.
The DO output signals can be activated by protection zone‘s
start or trip signals or by the programmable logic functions.
The DI input can be used to block protection zone(s) or it can be
used as input into the programmable logic of the device.
Different type of permissive tripping conditions such as,
permissive under reach (PUTT), permissive over reach (POTT),
acceleration or blocking conditions can thus be implemented.
The relay‘s object control can be used to trip the breaker via the
―DI for remote open ctr‖ or ―DI for local open ctr‖ input of the
object. Outputs of the relay programmable logic can be
connected to ―DI for remote open crt‖ or ―DI for local open ctr‖
inputs via the internal ―Virtual output‖ signals.