ABB Relion 670 Series Technical Reference Manual page 525

1MRK505222-UUS C
8.3.2.1
8.3.2.2
Technical reference manual
Measurement principle
The residual voltage is measured continuously, and compared with the set values,
Pickup1 and Pickup2.
To avoid oscillations of the output PICKUP signal, a hysteresis has been included.
Time delay
The time delay for the two steps can be either definite time delay (DT) or inverse time
delay (TOV). 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:
TD
=
t
æ ö
- >
V Vpickup
ç ÷
>
Vpickup
è ø
ANSIEQUATION2422 V1 EN
where:
Un> Set value for step 1 and step 2
U Measured voltage
The type B curve is described as:
×
TD 480
=
t
æ ö
- >
V Vpickup
× -
32 0.5
ç ÷
>
Vpickup
è ø
ANSIEQUATION2423 V1 EN
The type C curve is described as:
×
TD 480
=
t
æ - > ö
V Vpickup
× -
32 0.5
ç ÷
>
Vpickup
è ø
ANSIEQUATION2421 V1 EN
The customer programmable curve can be created as:
-
0.035
2.0
+
0.035
3.0
Section 8
Voltage protection
(Equation 130)
(Equation 131)
(Equation 132)
519