ABB Relion 670 Series RES670, Technical Manual

Page: 295 / 888

9.2.7.2 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:
t
TD
V Vpickup
Vpickup
=
− >
>
EQUATION1625 V2 EN
(Equation 56)
where:
Vpickup
>
Set value for step 1 and step 2
V Measured voltage
The type B curve is described as:
t
TD
V Vpickup
Vpickup
=
⋅
⋅
− >
>
−
+
480
32 0 5
0 035
.
.
ANSIEQUATION2287 V3 EN
(Equation 57)
The type C curve is described as:
t
TD
V Vpickup
Vpickup
=
⋅
⋅
− >
>
−
+
480
32 0 5
0 035
.
.
ANSIEQUATION2288 V2 EN
(Equation 58)
The customer programmable curve is defined by the below equation, where A, B, C, D, k
and p are settings:
P
TD A
t D
V Vpickup
B C
Vpickup
×
= +
-
× -
æ ö
ç ÷
è ø
EQUATION1616 V1 EN
(Equation 59)
1MRK 511 365-UUS A
Section 9
Voltage protection
Phasor measurement unit RES670 2.1 ANSI 289
Technical manual