Woodward
Manual XRI1-ER
32
TD_XRI1-ER_12.03, Rev. C
7.4.7 Checking the external blocking and reset functions
The external blocking input inhibits e. g. the function of the high set element of the phase current. To test the
blocking function apply auxiliary supply voltage to the external blocking input of the relay (terminals C1/C1L or
C1/C1H). The time delay tI> 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 and alarm for the high 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 C2/C2L or C2/C2H). The display and LED indications should be reset immediately.
7.4.8 Test of the CB failure protection
For testing the tripping time a test current of about 1 times the rated current has to be injected. The timer is
started upon tripping of the relay of a protection function (IE>, IE>>) and stopped as soon as the relay for the
CB failure protection has picked up. Message "CBFP" is displayed. The tripping time ascertained by the timer
should not deviate more than 1% or, at short trip delay, less than 10 ms from the set tripping time.
Alternatively, the timer can be started when the aux. voltage and the test current are injected simultaneously.
The timer stops when the corresponding output relay for circuit breaker failure protection trips.
In this case the previously measured tripping delay (see section 6.4.5) has to be subtracted from the total trip-
ping time measured.
