To prevent accidental tripping before active power exceeds under powers pick-up setting, low power
block-setting can be used. LPB-signal deactivates when measured active power exceeds pick-up
settings reset value (1.03xPset).
Table. 5.4.18. - 150. Pick-up characteristics settings
Name
Description
Range
Step
Default
Pset<
Pick-up setting
0.0 … 100000kW
0.01kW
100kW
Pset<
Low power block
0.0 … 100000kW
0.01kW
50kW
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 at 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 voltage 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). For detailed information on this delay type refer to
chapter General properties of a protection function.
Events and registers
The UPW 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 UPW function offers four
independent instances which events are segregated for each instance operation.
12 last registers are available in the function where the triggering event of the function (start, trip or
blocked) is recorded with time stamp and process data values.
Table. 5.4.18. - 151. Event codes of the UPW function.
Event Number
Event channel
Event block name
Event Code
Description
6464
101
UPW1
0
Start ON
6465
101
UPW1
1
Start OFF
6466
101
UPW1
2
Trip ON
6467
101
UPW1
3
Trip OFF
AQ-F255
Instruction manual
Version: 2.00
© Arcteq Relays Ltd
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