Measurement Principle; Time Delay - ABB REG650 Technical Manual

1MRK 502 034-UEN -
8.3.7.1
8.3.7.2
Technical Manual

Measurement principle

The residual voltage is measured continuously, and compared with the set values,
U1> and U2>.
To avoid oscillations of the output START signal, a hysteresis has been included.

Time delay

The time delay for step 1 can be either definite time delay (DT) or inverse time
delay (IDMT). Step 2 is always definite time delay (DT). For the inverse time
delay three different modes are available:
• inverse curve A
• inverse curve B
• inverse curve C
The type A curve is described as:
k
=
t
- >
æ ö
U U
ç ÷
>
è U ø
IEC09000051 V1 EN
The type B curve is described as:
×
k 480
=
t
æ - > ö
U U
ç × - ÷
32 0.5
è ø
>
U
IECEQUATION2287 V1 EN
The type C curve is described as:
×
k 480
=
t
æ - > ö
U U
ç × - ÷
32 0.5
è ø
>
U
IECEQUATION2288 V1 EN
The details of the different inverse time characteristics are shown in section
"Inverse time characteristics".
TRIP signal issuing requires that the residual overvoltage 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 (IDMT).
-
0.035
2.0
+
0.035
3.0
Section 8
Voltage protection
(Equation 73)
(Equation 74)
(Equation 75)
233