User-Programmable Inverse-Time Characteristics; Ri And Rd-Type Inverse-Time Characteristics - ABB RER620 Technical Manual

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10.2.1.3
10.2.1.4
RER620
Technical Manual

User-programmable inverse-time characteristics

The user can define curves by entering parameters into the following standard formula:
t[s] Trip time (in seconds)
set Curve parameter A
A
B set Curve parameter B
C set Curve parameter C
set Curve parameter E
E
I Measured current
set Pickup value
I>
set Time multiplier
k

RI and RD-type inverse-time characteristics

The RI-type simulates the behavior of electromechanical relays. The RD-type is a
ground-fault specific characteristic.
The RI-type is calculated using the formula
⎛
⎜
k
=
t s [ ]
⎜
>
I
⎜ ⎜
− ×
0 339 0 236 . .
⎝
I
The RD-type is calculated using the formula
⎛ I
= − ×
t s [ ] 5 8 1 35 In . .
⎜
× >
k I
⎝
t[s] Trip time (in seconds)
set Time multiplier
k
I Measured current
I>set Pickup value
General function block features
⎞
⎟
⎟
⎟ ⎟
⎠
⎞
⎟
⎠
Section 10
(Equation 59)
(Equation 60)
(Equation 61)
521