ABB RED650 - Measurement Principle; Time Delay

available: if the voltage is lower than the set blocking level, the function is blocked
and no START or TRIP signal is generated. The time delay characteristic is
individually chosen for each step and can be either definite time delay or inverse
time delay.
To avoid oscillations of the output START signal, a hysteresis has been included.
9.1.7.1 Measurement principle
M15326-6 v7
Depending on the value of the ConnType parameter, UV2PTUV can be set to
measure phase-to-earth fundamental value, phase-to-phase fundamental value,
phase-to-earth true RMS value or phase-to-phase true RMS value, and compares it
against the set values, U1< and U2<. The voltage-related settings are made in
percentage of the base voltage which is set in kV phase-to-phase voltage. This
means operation for phase-to-earth voltage under:
UBase kV
(%)
( )
3
·
U
EQUATION1429 V3 EN-US (Equation 35)
and operation for phase-to-phase voltage under:
U (%) UBase(kV)< ×
EQUATION1990 V1 EN-US (Equation 36)
When the phase-to-earth voltage measurement is selected, the
function automatically introduces division of the base value by the
square root of three.
9.1.7.2 Time delay
M15326-10 v11
The time delay for the two steps can be either definite time delay (DT) or inverse
time delay (IDMT). For the inverse time delay three different modes are available:
• inverse curve A
• inverse curve B
• customer programmable inverse curve
The type A curve is described as:
n
n
k
t
U U
U
=
æ ö
< -
ç ÷
<
è ø
EQUATION1431 V2 EN-US
(Equation 37)
Section 9 1MRK 505 394-UEN A
Voltage protection
232 Line differential protection RED650 2.2 IEC
Technical manual