Function blocking
The block signal is checked in the beginning of each program cycle. The blocking signal is received
from the blocking matrix in the function's dedicated input. Additionally, the non-directional overcurrent
function includes an internal inrush harmonic blocking option which is applied according to the
parameters set by the user. 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. 5.3.2 - 51. Internal inrush harmonic blocking settings.
Name
Range
Step
Default
Description
Inrush harmonic blocking (internal-
only trip)
0: No
1: Yes
-
0: No
Enables and disables the 2
nd
harmonic
blocking.
2
nd
harmonic blocking limit (Iharm/
Ifund)
0.10…50.00%I
fund
0.01%I
fund
0.01%I
fund
Defines the limit of the 2
nd
harmonic
blocking.
If the blocking signal is active when the pick-up element activates, a BLOCKED signal is generated and
the function does not process the situation further. If the START function has been activated before the
blocking signal, it resets and the release time characteristics are processed similarly to when the pick-
up signal is reset.
The blocking of the function causes an HMI display event and a-time stamped blocking event with
information of the startup current values and its fault type to be issued.
The blocking signal can also be tested in the commissioning phase by a software switch signal when
the relay's testing mode "Enable stage forcing" is activated (
General
→
Device).
The variables the user can set are binary signals from the system. The blocking signal needs to reach
the device minimum of 5 ms before the set operating delay has passed in order for the blocking to
activate in time.
Operating time characteristics for trip and reset
This function supports definite time delay (DT) and inverse definite minimum time delay (IDMT). For
detailed information on these delay types please refer to the chapter "General properties of a protection
function" and its section "Operating time characteristics for trip and reset".
A
AQ
Q-M255
-M255
Instruction manual
Version: 2.06
64
© Arcteq Relays Ltd
IM00020
Содержание AQ-M255
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