The function outputs the 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 signal. 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 volts-per-hertz overexcitation
function.
Figure. 5.3.14 - 143. Simplified function block diagram of the V/Hz> function.
Measured input
The function block uses analog system voltages and system frequency measurement values.
Table. 5.3.14 - 130. Measurement inputs of the volts-per-hertz function.
Signal
Description
Time base
U
L1
RMS
U
L1
System voltage RMS
5ms
U
L2
RMS
U
L2
System voltage RMS
5ms
U
L3
RMS
U
L3
System voltage RMS
5ms
U
L12
RMS
U
L12
System voltage RMS
5ms
U
L23
RMS
U
L23
System voltage RMS
5ms
U
L31
RMS
U
L31
System voltage RMS
5ms
f
Measured system frequency f
5ms
Pick-up
The
Pick-up V/Hz > (% of nominal) setting parameter controls the pick-up of the volts-per-
hertz function. This defines the maximum measured voltage allowed in relation to the measured
frequency before action from the function. The function constantly calculates the ratio between the
Pick-up V/Hz (% of nominal)and the calculated U
meas
/
f
meas
ratio. The reset ratio of 97 % is built into
the function and is always relative to the
Pick-up V/Hz (% of nominal)value.
A
AQ
Q-T215
-T215
Instruction manual
Version: 2.04
196
