Application Guide - NP900 Series
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A996A
3.2.5.3
R
EAL
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TIME INFO DISPLAYED OF THE FUNCTION
The relays Info-page displays useful information in real time of the state of the protection
function either through relays HMI display or with SMART9 software when connection
there is a connection to relay and Live Edit-mode is activated.
Name
Unit
Description
U0> Pick-up setting
V
Required residual voltage on the primary side for the
relay to trip.
Detected U0I0 angle (fi)
Deg
The angle in degrees between the monitored residual
voltage and current
I0 Magnitude
xI0n
Per-unit-value of the monitored residual current
I0 Wattmetric I0xCos(fi)
xI0n
I0 Varmetric I0xSin(fi)
xI0n
I0 direction now
Undefined
Forward
Reverse
Detected direction of the residual current.
I0 meas / I0 set now
xI0n
Ratio between monitored residual current and pick-up
setting
U0 meas now
%U0n
The measured voltage in the chosen voltage channel.
Expected operating time
s
Displays the expected operating time in case a fault
occurs
Time remaining to trip
s
When the relay has picked up and is counting time
towards pick-up
3.2.5.4
F
UNCTION 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 passed for blocking to be
active in time.