Woodward
Manual MRIK3-C EN
70
DOK-TD-MRIK3-C Rev. A
7.4.8
Checking the AR blocking function
First it must be ensured that the function is assigned to a digital input. If the digital input is acti-
vated, the 0
I will light up red.
7.4.9
Checking the external blocking and reset functions
By means of the external blocking input, it is possible to block all protective functions. To give an
example, the blocking function of the phase current high set element is described.
This can be tested by first setting the parameter for the phase current high set element to „BLOC“
and then connecting the auxiliary voltage to to the digital input reserved for this purpose.
The phase current low set element I> should be set to EXIT for this test. Inject a test current which
could cause a high set (I>>) tripping. Observe that there is no trip of any assigned output relay of
the high set or low set element.
Remove the auxiliary supply voltage from the blocking input. Inject a test current to trip the relay
(message „TRIP“ on the display). Interrupt the test current and apply auxiliary supply voltage to the
external reset input of the relay (terminals C8/D8). The display and LED indications should be reset
immediately.
7.4.10
Testing the external blocking with Block/Trip function
In order to simplify things, the short-circuit stage is to be tested here as described in Chapter 7.4.9.
For this purpose, the parameter for the Block/Trip function must be set to "TR_B" (first value in the
blocking menu of the protection functions Chapter 6.12.1. The appertaining Block/Trip time should
be longer than the set tripping time tI>>. Here, too, a current is impressed which should make the
short-circuit stage trip. At the same time the blocking input must be activated. The easiest way to
do this is to set the alarm relay to the blocking input. After the Block/Trip time has expired, tripping
will take place. Tripping takes place when:
the blocking input has been set
a tripping stage has been excited
the appertaining tripping time has expired
the Block/trip time has expired
If the Block/Trip time is set shorter than the tripping time, tripping will only take place after the trip-
ping time has expired.
