ABB RELION 670 Series Technical Manual page 610

Section 9
Voltage protection
9.1.7.1 Measurement principle
Depending on the set
phase voltages and compare against set values,
OpMode2 influence the requirements to activate the PICKUP outputs. Either 1 out of 3 , 2 out
and
of 3 , or 3 out of 3 measured voltages have to be lower than the corresponding set point to issue
the corresponding PICKUP signal.
To avoid oscillations of the output PICKUP signal, a hysteresis has been included.
9.1.7.2 Time delay
The time delay for the two steps can be either definite time delay (DT) or inverse time
undervoltage (TUV). 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:
=
t
Vpickup
Vpickup
ANSIEQUATION1431 V1 EN-US
where:
Vpickup<
V
The type B curve is described as:
=
t
æ
×
ç
32
è
EQUATION1608 V1 EN-US
The customer programmable curve can be created as:
604
When phase-to-ground voltage measurement is selected the function
automatically introduces division of the base value by the square root of three.
ConnType value, UV2PTUV (27) measures phase-to-ground or phase-to-
TD
< -
V
<
Set value for step 1 and step 2
Measured voltage
×
TD 480
+
0.055
2.0
ö
Vpickup < -V
-
÷
0.5
ø
<
Vpickup
Pickup1 and Pickup2 . The parameters OpMode1
1MRK 502 066-UUS B
M15326-6 v6
M15326-10 v12
(Equation 170)
(Equation 171)
Technical manual