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. Additionally, directional
earth-fault protection includes internal inrush harmonic blocking option which is applied by user set
parameter. 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.
Table. 5.4.5. - 79. Internal inrush harmonic blocking settings
Name
Description
Range
Step
Default
Inrush Harmonic Blocking (Internal
Only Trip)
2
nd
harmonic blocking
enable/disable
0:No
1:Yes
-
No
2
nd
Harmonic Block Limit (Iharm/Ifund)
2
nd
harmonic blocking limit.
0.10…
50.00*%Ifund
0.01*%Ifund 0.01*%Ifund
If blocking signal is active when pick-up element activates 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 an 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 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 DEF 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 DEF 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. 5.4.5. - 80. Event codes of the DEF-function instances.
Event Number
Event channel
Event block name
Event Code
Description
5184
81
DEF1
0
Start ON
5185
81
DEF1
1
Start OFF
5186
81
DEF1
2
Trip ON
5187
81
DEF1
3
Trip OFF
5188
81
DEF1
4
Block ON
5189
81
DEF1
5
Block OFF
AQ-F255
Instruction manual
Version: 2.00
81
© Arcteq Relays Ltd