Blocking - ABB REG650 Technical Manual

1MRK 502 043-UUS B
9.1.7.3
9.1.7.4
Technical Manual
TD
=
t
< -
Vpickup V
<
Vpickup
ANSIEQUATION1431 V1 EN
The type B curve is described as:
×
TD 480
=
t
æ
Vpickup < -V
× -
ç 32 0.5
è
<
Vpickup
EQUATION1608 V1 EN
The lowest voltage is always used for the inverse time delay integration. The details of
the different inverse time characteristics are shown in section
characteristics".
Trip signal issuing requires that the undervoltage condition continues for at least the
user set time delay. This time delay is set by the parameter t1 and t2 for definite time
mode (DT) and by some special voltage level dependent time curves for the inverse
time mode (TUV). If the pickup condition, with respect to the measured voltage ceases
during the delay time, the corresponding pickup output is reset.

Blocking

It is possible to block Two step undervoltage protection (UV2PTUV ,27) partially or
completely, by binary input signals or by parameter settings, where:
BLOCK:
BLK1:
BLK2:
Design
The voltage measuring elements continuously measure the three phase-to-neutral
voltages or the three phase-to-phase voltages. Recursive fourier filters or true RMS
filters of input voltage signals are used. The voltages are individually compared to the
set value, and the lowest voltage is used for the inverse time characteristic integration.
A special logic is included to achieve the 1 out of 3, 2 out of 3 and 3 out of 3 criteria to
fulfill the PICKUP condition. The design of Two step undervoltage protection
UV2PTUV (27) is schematically shown in
+
0.055
2.0
ö
÷
ø
blocks all outputs
blocks all pickup and trip outputs related to step 1
blocks all pickup and trip outputs related to step 2
Figure
Section 9
Voltage protection
21.3 "Inverse time
119.
(Equation 71)
(Equation 72)
255