VAMP 140
Overcurrent and earth-fault relay
Technical description
VAMP Ltd
30
Vamp 24h support phone +358 (0)40 573 6316
VM140.EN011
3.5.
Fast busbar short-circuit protection
based on blockings
Figure 3.5-1 A fast busbar short-circuit protection based on blocking of
overcurrent relays. A blocking signal is issued, if one of the overcurrent
relays on the outgoing feeders starts. The blocking signal is configured to
block the high-set stage I>> of the overcurrent relay on the infeeder. The
operating time t>> of the high-set stage of the infeeder can be set as low as
70 ms, because the operating time of the start contacts of the overcurrent
relays of the outgoing feeders is well under 50 ms.