Function blocking
In the blocking element the block signal is checked in the beginning of each program cycle. Blocking
signal is received from the blocking matrix for the function dedicated input. If the blocking signal is not
activated when the pick-up element activates, a START signal is generated and the function proceeds
to the time characteristics calculation.
If blocking signal is active when pick-up element activates a BLOCKED signal will be generated and the
function shall not process the situation further. If START function has been activated before blocking
signal it will reset and the release time characteristics are processed as in case of when pick-up signal
is reset.
From blocking of the function a HMI display event as well as time stamped blocking event with
information of the startup current values and fault type is issued.
Blocking signal can be tested also in the commissioning phase of the stage by software switch signal
when relay common and global testing mode is activated.
User settable variables are binary signals from the system. Blocking signal needs to reach the IED
minimum of 5 ms before the set operating delay has passedfor blocking to be active in time.
Operating time characteristics for trip and reset
This function supports de nite time delay (DT) and inverse de nite minimum time (IDMT) delay types.
For detailed information on these delay types refer to chapter General properties of a protection
function.
Events and registers
The HOC function generates events and registers from the status changes of start, trip and blocked.
To main event buffer is possible to select status “On” or “Off” messages. The HOC function offers four
independent instances which events are segregated for each instance operation.
In the function is available 12 last registers where the triggering event of the function (start, trip or
blocked) is recorded with time stamp and process data values.
Table. 5.4.8. - 97. Event codes of the HOC function instances.
Event Number
Event channel
Event block name
Event Code
Description
2368
37
HOC1
0
Start ON
2369
37
HOC1
1
Start OFF
2370
37
HOC1
2
Trip ON
2371
37
HOC1
3
Trip OFF
2372
37
HOC1
4
Block ON
2373
37
HOC1
5
Block OFF
2432
38
HOC2
0
Start ON
2433
38
HOC2
1
Start OFF
2434
38
HOC2
2
Trip ON
2435
38
HOC2
3
Trip OFF
2436
38
HOC2
4
Block ON
2437
38
HOC2
5
Block OFF
2496
39
HOC3
0
Start ON
AQ-F255
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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