IsetI01 0.10 …
200.00% 0.01% 20.00%
Pick-up setting for THD alarm element from the residual current I01. The measured
THD value has to be over this setting to activate the alarm signal.
IsetI02 0.10 …
200.00% 0.01% 20.00%
Pick-up setting for THD alarm element from the residual current I02. The measured
THD value has to be over this setting to activate the alarm signal.
The pick-up activation of the function is not directly equal to start-signal generation of the function.
Start signal is allowed if blocking condition is not active.
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 activation and reset
The operating timers’ behavior of the function can be set for activation and the cold load pick up
situation monitoring and release.
In the following table are presented the setting parameters for the function time characteristics.
Table. 5.6.7. - 243. Operating time characteristics setting parameters.
Name
Range
Step
Default
Description
Tpha
0.000…
1800.000s
0.005s 10.000s Delay time setting for the alarm timer from the phase currents measured
THD.
TI01
0.000…
1800.000s
0.005s 10.000s Delay time setting for the alarm timer from the residual current I01
measured THD.
TI02
0.000…
1800.000s
0.005s 10.000s Delay time setting for the alarm timer from the residual current I02
measured THD.
Events and registers
The THD function generates events and registers from the status changes of the alarm function when it
is activated. Recorded signals are Start and Alarm signals per monitoring element and common
blocked signals. To main event buffer is possible to select status “On” or “Off” messages.
In the function is available 12 last registers where the triggering event of the function (THD start, alarm
or blocked) is recorded with time stamp and process data values.
Table. 5.6.7. - 244. Event codes of the THD function
Event Number
Event channel
Event block name
Event Code
Description
AQ-F255
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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