The “In” magnitude refers to user set nominal current which can be in range of 0.2…10A, typically
0.2A, 1A or 5A. With its own current measurement card, the IED will measure secondary currents from
0.001A up to 250A. To this relation the pick-up setting in secondary amperes will vary.
Function blocking
In the blocking element the blocking signals are 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, an HMI display event as well as time stamped blocking event with
information of the startup current values and fault type are 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
The operating timers’ behavior of the function can be set for trip signal and for the release of the
function in case the pick-up element is reset before the trip time has been reached. There are three
basic operating modes available for the function. Instant operation gives the trip signal with no
additional time delay simultaneously with start signal. De nite time operation (DT) will give trip signal
with user given time delay regardless of the measured current for as long as the current is above/below
the Xset value and thus pick-up element is active (independent time characteristics).
Inverse de nite minimum time (IDMT) will give the trip signal in time which is in relation of the set pick-
up value Xset and measured value Xm (dependent time characteristics). For the IDMT operation is
available IEC and IEEE/ANSI standard characteristics as well as user settable parameters. Please note
that in IDMT mode De nite (Min) operating time delay is also in use de ning the minimum time for
protection tripping. If this function is not desired this parameter should be set to 0 seconds.
AQ-T216
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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