Measurement Principle - ABB REG650 Technical Manual

1MRK 502 043-UUS B
9.2.7.1
9.2.7.2
Technical Manual
When phase-to-ground voltage measurement is selected the function
automatically introduces division of the base value by the square root
of three.

Measurement principle

All the three voltages are measured continuously, and compared with the set values,
Pickup1 and Pickup2. The parameters OpMode1 and OpMode2 influence the
requirements to activate the PICKUP 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 PICKUP signal.
To avoid oscillations of the output PICKUP signal, a hysteresis has been included.
Time delay
The time delay for step 1 can be either definite time delay (DT) or inverse time
overvoltage (TOV). 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:
TD
t
=
V Vpickup
− >
Vpickup
>
EQUATION1625 V2 EN
The type B curve is described as:
TD 480
⋅
t
= −
V Vpickup
− >
32 0 5 .
⋅ −
Vpickup
>
ANSIEQUATION2287 V2 EN
The type C curve is described as:
TD 480
⋅
t
= +
V Vpickup
− >
32 0 5 .
⋅ −
Vpickup
>
ANSIEQUATION2288 V2 EN
0 035 .
0 035 .
Section 9
Voltage protection
(Equation 75)
(Equation 76)
(Equation 77)
261