ABB RELION REX640 Technical Manual page 621

1MRS759142 F
For body weight of 70 kg:
where
C
is the surface layer derating factor
s
ρ
is the surface material resistivity in Ω·m
s
ρ is the resistivity of the earth beneath the surface material in Ω·m
If no protective surface layer is used, then
The equations of IEEE Std 80-2013 are in IFPTOC function modelled with following
simplified equation, with only one parameter
With setting
magnitude can be adjusted. For body weight of 70 kg,
IEEE multiplier equals 157.0.
In IFPTOC, the protection operate time
Example numerical values of the permissible touch voltage U
fault duration t
Table 633
equals 157.0.
Table 633: Numerical example of the values of the permissible touch voltages U
as a function of the fault duration t
REX640
Technical Manual
IEEE multiplier operate time as a function of estimated touch voltage
according to standard IEEE80 follows equation below:
according to standard IEEE80 are shown in
f
assume body weight of 70 kg,
C ρ ρ .
=1 and =
s s
IEEE multiplier :
C
=1,
s
t as a function of estimated touch voltage
C ρ ρ = 0 Ω·m, then IEEE multiplier
=1, =
s s
according to standard IEEE80 programmed
f
Protection functions
(Equation 128)
(Equation 129)
(Equation 130)
ρ ρ = 0 Ω·m, then
=
s
(Equation 131)
as a function of the
Tp
Table 633
. Values in
Tp
621