GEK-113308
MIWII Directional Power Protection System
2-9
2 PRODUCT DESCRIPTION
2.6 FUSE FAILURE (60). MIWII1000
2
2.6FUSE FAILURE (60). MIWII1000
The purpose of this unit is to verify the existence of one or more phases without voltage, but with current circulating through
the unit.
All the units incorporated in the relay (40, 32) are blocked if a fuse failure, or a disconnected generator (open breaker)
condition is detected. The disconnected generator detection is performed by sensing a dedicated input to the 52b auxiliary
contact. When this input is activated, the generator is disconnected from the network.
It is essential for MIWII units to monitor the breaker status, using an auxiliary contact type 52b. Otherwise, we must not
connect this input, simulating a connected generator situation, in order to maintain the protection units enabled.
V_2/V_1>0,25 p.u.
V_1<0,5 p.u.
I>0,075 p.u.
V_1>0,7 p.u.
I<0,05 p.u.
0
20 ms
80 ms
0
FUSE
FAILURE
Breaker OPEN