21/07/2010
7
MRAR 01/96 C
Protection Trip (27)
When a tripping command occurs from the protection before the fault timer has expired, the unit
changes from the "Starting" status to the "Cycle" status switching the circuit breaker to off. (see also
para 4.3.4).
Circuit Breaker Energy (22)
Because the circuit breaker needs a certain time between two reclosings in order to trip again, the ready
signal of the circuit breaker; auxiliary voltage at terminal 22; is checked before a new reclosing can take
place. (see also para 4.3.9).
Synchronism Check (23)
In order to prevent a reclosing of the unit at an asynchronous phase position, input 23 is connected to a
synchronising unit. If no synchronous control is necessary, the auxiliary voltage is applied to terminal
23.
External Blocking (24) and External Reset (25)
The unit is blocked when applying voltage to terminal 24. This blocking can only be removed by
applying the auxiliary volatge to terminal 25. Blocking has priority during the simultaneous activation
of inputs 24 and 25.
Reserve (26)
This input is not used at this time.
Common Point (15)
All the listed inputs have the common point connection L- or N.
4.1.2 Output Relays
The
MRAR
has 5 output relays. One relay with two change-over contacts for tripping and other four
with a single change-over contact are used for siginalling:
•
•
•
•
Switch on command to the circuit breaker (31, 29, 33, 32, 30, 34)
•
•
•
•
Blocking of the high set trip (38, 36, 40)
•
•
•
•
Signal "AR in Progress" (43, 41, 45)
•
•
•
•
Signal "AR Blocked" (47, 49, 51)
•
•
•
•
Signal "Self-supervision" (50, 48, 52)
4.2 LED's
The front panel consists of five push buttons for control and adjustment and twenty LED's for
indication. The LED's on the left hand side next to the display indicate the status, error messages and
AR results. The LED's on the left under the status LED's are provided for adjustments, their functions
are shown by the legend next to the LED.
