• operating mode selections
• setting parameters
• digital inputs and logic signals
• measured and pre-processed current magnitudes.
The function's outputs are START, TRIP and BLOCKED signals which can be used for direct I/O
controlling and user logic programming. The function generates general time-stamped ON/OFF events
to the common event buffer from each of the three (3) output signals. In the instant operating mode the
function outputs START and TRIP events simultaneously with an equivalent time stamp. The time stamp
resolution is 1 ms. The function also provides a resettable cumulative counter for the START, TRIP and
BLOCKED events.
The following figure presents a simplified function block diagram of the non-directional earth fault
function.
Figure. 5.4.4 - 92. Simplified function block diagram of the I0> fucntion.
Measured input
The function block uses analog current measurement values. The user can select the monitored
magnitude to be equal either to RMS values, to TRMS values, or to peak-to-peak values. TRMS mode
uses values from the whole harmonic spectrum of 32 components. Peak-to-peak mode picks
measurement values directly from the samples. A -20 ms averaged value of the selected magnitude is
used for pre-fault data registering.
Table. 5.4.4 - 70. Measurement inputs of the I0> function.
Signal
Description
Time base
I01RMS
RMS measurement of coarse residual current measurement input I01
5 ms
I01TRMS
TRMS measurement of coarse residual current measurement input I01
5 ms
I01PP
Peak-to-peak measurement of coarse residual current measurement input I01
5 ms
I02RMS
RMS measurement of sensitive residual current measurement input I02
5 ms
I02TRMS
TRMS measurement of coarse sensitive current measurement input I02
5 ms
I02PP
Peak-to-peak measurement of sensitive residual current measurement input I02
5 ms
I0Calc
RMS value of the calculated zero sequence current from the three phase currents
5 ms
A
AQ
Q-C215
-C215
Instruction manual
Version: 2.07
118
© Arcteq Relays Ltd
IM00040