ABB RED650 - Measurement Principle; Time Delay

The setting of the analog inputs are given as primary phase-to-earth or phase-to-
phase voltage. OV2PTOV will operate if the voltage gets higher than the set
percentage of the set base voltage UBase. This means operation for phase-to-earth
voltage over:
(%) ( )
3
U UBase kV> ×
EQUATION1434 V1 EN-US (Equation 41)
and operation for phase-to-phase voltage over:
U (%) UBase(kV)> ×
EQUATION1993 V1 EN-US (Equation 42)
When phase-to-earth voltage measurement is selected the function
automatically introduces division of the base value by the square
root of three.
9.2.7.1 Measurement principle
M15330-6 v6
All the three voltages are measured continuously, and compared with the set
values, U1> for Step 1 and U2> for Step 2. The parameters OpMode1 and
OpMode2 influence the requirements to activate the START outputs. Either 1 out of
3, 2 out of 3 or 3 out of 3 measured voltages have to be higher than the
corresponding set point to issue the corresponding START signal.
To avoid oscillations of the output START signal, a hysteresis is included.
9.2.7.2 Time delay
M15330-10 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 four different modes are available:
• inverse curve A
• inverse curve B
• inverse curve C
• customer programmable inverse curve
The type A curve is described as:
n
n
k
t
U U
U
=
æ ö
- >
ç ÷
>
è ø
IECEQUATION2422 V1 EN-US (Equation 43)
Section 9 1MRK 505 394-UEN A
Voltage protection
246 Line differential protection RED650 2.2 IEC
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